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From ka...@apache.org
Subject [2/4] [HELIX-209] Moving rebalancer code around, take 2
Date Wed, 16 Oct 2013 00:09:45 GMT
http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/PartitionedRebalancerContext.java
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diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/PartitionedRebalancerContext.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/PartitionedRebalancerContext.java
new file mode 100644
index 0000000..9d24e68
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/PartitionedRebalancerContext.java
@@ -0,0 +1,373 @@
+package org.apache.helix.controller.rebalancer.context;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.HelixConstants.StateModelToken;
+import org.apache.helix.api.Partition;
+import org.apache.helix.api.id.ParticipantId;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.controller.rebalancer.RebalancerRef;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.IdealState.RebalanceMode;
+import org.apache.helix.model.StateModelDefinition;
+import org.codehaus.jackson.annotate.JsonIgnore;
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
+
+import com.google.common.collect.Maps;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * RebalancerContext for a resource whose subunits are partitions. In addition, these partitions can
+ * be replicated.
+ */
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class PartitionedRebalancerContext extends BasicRebalancerContext implements
+    ReplicatedRebalancerContext {
+  private Map<PartitionId, Partition> _partitionMap;
+  private boolean _anyLiveParticipant;
+  private int _replicaCount;
+  private int _maxPartitionsPerParticipant;
+  private final RebalanceMode _rebalanceMode;
+
+  /**
+   * Instantiate a DataRebalancerContext
+   */
+  public PartitionedRebalancerContext(RebalanceMode rebalanceMode) {
+    _partitionMap = Collections.emptyMap();
+    _replicaCount = 1;
+    _anyLiveParticipant = false;
+    _maxPartitionsPerParticipant = Integer.MAX_VALUE;
+    _rebalanceMode = rebalanceMode;
+  }
+
+  /**
+   * Get a map from partition id to partition
+   * @return partition map (mutable)
+   */
+  public Map<PartitionId, Partition> getPartitionMap() {
+    return _partitionMap;
+  }
+
+  /**
+   * Set a map of partition id to partition
+   * @param partitionMap partition map
+   */
+  public void setPartitionMap(Map<PartitionId, Partition> partitionMap) {
+    _partitionMap = Maps.newHashMap(partitionMap);
+  }
+
+  /**
+   * Get the set of partitions for this resource
+   * @return set of partition ids
+   */
+  @JsonIgnore
+  public Set<PartitionId> getPartitionSet() {
+    return _partitionMap.keySet();
+  }
+
+  /**
+   * Get a partition
+   * @param partitionId id of the partition to get
+   * @return Partition object, or null if not present
+   */
+  @JsonIgnore
+  public Partition getPartition(PartitionId partitionId) {
+    return _partitionMap.get(partitionId);
+  }
+
+  @Override
+  public boolean anyLiveParticipant() {
+    return _anyLiveParticipant;
+  }
+
+  /**
+   * Indicate if this resource should be assigned to any live participant
+   * @param anyLiveParticipant true if any live participant expected, false otherwise
+   */
+  public void setAnyLiveParticipant(boolean anyLiveParticipant) {
+    _anyLiveParticipant = anyLiveParticipant;
+  }
+
+  @Override
+  public int getReplicaCount() {
+    return _replicaCount;
+  }
+
+  /**
+   * Set the number of replicas that each partition should have
+   * @param replicaCount
+   */
+  public void setReplicaCount(int replicaCount) {
+    _replicaCount = replicaCount;
+  }
+
+  /**
+   * Get the maximum number of partitions that a participant can serve
+   * @return maximum number of partitions per participant
+   */
+  public int getMaxPartitionsPerParticipant() {
+    return _maxPartitionsPerParticipant;
+  }
+
+  /**
+   * Set the maximum number of partitions that a participant can serve
+   * @param maxPartitionsPerParticipant maximum number of partitions per participant
+   */
+  public void setMaxPartitionsPerParticipant(int maxPartitionsPerParticipant) {
+    _maxPartitionsPerParticipant = maxPartitionsPerParticipant;
+  }
+
+  /**
+   * Get the rebalancer mode of the resource
+   * @return RebalanceMode
+   */
+  public RebalanceMode getRebalanceMode() {
+    return _rebalanceMode;
+  }
+
+  @Override
+  @JsonIgnore
+  public Map<PartitionId, Partition> getSubUnitMap() {
+    return getPartitionMap();
+  }
+
+  /**
+   * Generate a default configuration given the state model and a participant.
+   * @param stateModelDef the state model definition to follow
+   * @param participantSet the set of participant ids to configure for
+   */
+  @JsonIgnore
+  public void generateDefaultConfiguration(StateModelDefinition stateModelDef,
+      Set<ParticipantId> participantSet) {
+    // the base context does not understand enough to know do to anything
+  }
+
+  /**
+   * Convert a physically-stored IdealState into a rebalancer context for a partitioned resource
+   * @param idealState populated IdealState
+   * @return PartitionedRebalancerContext
+   */
+  public static PartitionedRebalancerContext from(IdealState idealState) {
+    PartitionedRebalancerContext context;
+    switch (idealState.getRebalanceMode()) {
+    case FULL_AUTO:
+      FullAutoRebalancerContext.Builder fullAutoBuilder =
+          new FullAutoRebalancerContext.Builder(idealState.getResourceId());
+      populateContext(fullAutoBuilder, idealState);
+      context = fullAutoBuilder.build();
+      break;
+    case SEMI_AUTO:
+      SemiAutoRebalancerContext.Builder semiAutoBuilder =
+          new SemiAutoRebalancerContext.Builder(idealState.getResourceId());
+      for (PartitionId partitionId : idealState.getPartitionIdSet()) {
+        semiAutoBuilder.preferenceList(partitionId, idealState.getPreferenceList(partitionId));
+      }
+      populateContext(semiAutoBuilder, idealState);
+      context = semiAutoBuilder.build();
+      break;
+    case CUSTOMIZED:
+      CustomRebalancerContext.Builder customBuilder =
+          new CustomRebalancerContext.Builder(idealState.getResourceId());
+      for (PartitionId partitionId : idealState.getPartitionIdSet()) {
+        customBuilder.preferenceMap(partitionId, idealState.getParticipantStateMap(partitionId));
+      }
+      populateContext(customBuilder, idealState);
+      context = customBuilder.build();
+      break;
+    default:
+      Builder baseBuilder = new Builder(idealState.getResourceId());
+      populateContext(baseBuilder, idealState);
+      context = baseBuilder.build();
+      break;
+    }
+    return context;
+  }
+
+  /**
+   * Update a builder subclass with all the fields of the ideal state
+   * @param builder builder that extends AbstractBuilder
+   * @param idealState populated IdealState
+   */
+  private static <T extends AbstractBuilder<T>> void populateContext(T builder,
+      IdealState idealState) {
+    String replicas = idealState.getReplicas();
+    int replicaCount = 0;
+    boolean anyLiveParticipant = false;
+    if (replicas.equals(StateModelToken.ANY_LIVEINSTANCE.toString())) {
+      anyLiveParticipant = true;
+    } else {
+      replicaCount = Integer.parseInt(replicas);
+    }
+    if (idealState.getNumPartitions() > 0 && idealState.getPartitionIdSet().size() == 0) {
+      // backwards compatibility: partition sets were based on pref lists/maps previously
+      builder.addPartitions(idealState.getNumPartitions());
+    } else {
+      for (PartitionId partitionId : idealState.getPartitionIdSet()) {
+        builder.addPartition(new Partition(partitionId));
+      }
+    }
+    builder.anyLiveParticipant(anyLiveParticipant).replicaCount(replicaCount)
+        .maxPartitionsPerParticipant(idealState.getMaxPartitionsPerInstance())
+        .participantGroupTag(idealState.getInstanceGroupTag())
+        .stateModelDefId(idealState.getStateModelDefId())
+        .stateModelFactoryId(idealState.getStateModelFactoryId());
+    RebalancerRef rebalancerRef = idealState.getRebalancerRef();
+    if (rebalancerRef != null) {
+      builder.rebalancerRef(rebalancerRef);
+    }
+  }
+
+  /**
+   * Builder for a basic data rebalancer context
+   */
+  public static final class Builder extends AbstractBuilder<Builder> {
+    /**
+     * Instantiate with a resource
+     * @param resourceId resource id
+     */
+    public Builder(ResourceId resourceId) {
+      super(resourceId);
+    }
+
+    @Override
+    protected Builder self() {
+      return this;
+    }
+
+    @Override
+    public PartitionedRebalancerContext build() {
+      PartitionedRebalancerContext context =
+          new PartitionedRebalancerContext(RebalanceMode.USER_DEFINED);
+      super.update(context);
+      return context;
+    }
+  }
+
+  /**
+   * Abstract builder for a generic partitioned resource rebalancer context
+   */
+  public static abstract class AbstractBuilder<T extends BasicRebalancerContext.AbstractBuilder<T>>
+      extends BasicRebalancerContext.AbstractBuilder<T> {
+    private final ResourceId _resourceId;
+    private final Map<PartitionId, Partition> _partitionMap;
+    private boolean _anyLiveParticipant;
+    private int _replicaCount;
+    private int _maxPartitionsPerParticipant;
+
+    /**
+     * Instantiate with a resource
+     * @param resourceId resource id
+     */
+    public AbstractBuilder(ResourceId resourceId) {
+      super(resourceId);
+      _resourceId = resourceId;
+      _partitionMap = Maps.newHashMap();
+      _anyLiveParticipant = false;
+      _replicaCount = 1;
+      _maxPartitionsPerParticipant = Integer.MAX_VALUE;
+    }
+
+    /**
+     * Add a partition that the resource serves
+     * @param partition fully-qualified partition
+     * @return Builder
+     */
+    public T addPartition(Partition partition) {
+      _partitionMap.put(partition.getId(), partition);
+      return self();
+    }
+
+    /**
+     * Add a collection of partitions
+     * @param partitions any collection of Partition objects
+     * @return Builder
+     */
+    public T addPartitions(Collection<Partition> partitions) {
+      for (Partition partition : partitions) {
+        addPartition(partition);
+      }
+      return self();
+    }
+
+    /**
+     * Add a specified number of partitions with a default naming scheme, namely
+     * resourceId_partitionNumber where partitionNumber starts at 0
+     * @param partitionCount number of partitions to add
+     * @return Builder
+     */
+    public T addPartitions(int partitionCount) {
+      for (int i = 0; i < partitionCount; i++) {
+        addPartition(new Partition(PartitionId.from(_resourceId, Integer.toString(i))));
+      }
+      return self();
+    }
+
+    /**
+     * Set whether any live participant should be used in rebalancing
+     * @param anyLiveParticipant true if any live participant can be used, false otherwise
+     * @return Builder
+     */
+    public T anyLiveParticipant(boolean anyLiveParticipant) {
+      _anyLiveParticipant = anyLiveParticipant;
+      return self();
+    }
+
+    /**
+     * Set the number of replicas
+     * @param replicaCount number of replicas
+     * @return Builder
+     */
+    public T replicaCount(int replicaCount) {
+      _replicaCount = replicaCount;
+      return self();
+    }
+
+    /**
+     * Set the maximum number of partitions to assign to any participant
+     * @param maxPartitionsPerParticipant the maximum
+     * @return Builder
+     */
+    public T maxPartitionsPerParticipant(int maxPartitionsPerParticipant) {
+      _maxPartitionsPerParticipant = maxPartitionsPerParticipant;
+      return self();
+    }
+
+    /**
+     * Update a DataRebalancerContext with fields from this builder level
+     * @param context DataRebalancerContext
+     */
+    protected final void update(PartitionedRebalancerContext context) {
+      super.update(context);
+      // enforce at least one partition
+      if (_partitionMap.isEmpty()) {
+        addPartitions(1);
+      }
+      context.setPartitionMap(_partitionMap);
+      context.setAnyLiveParticipant(_anyLiveParticipant);
+      context.setMaxPartitionsPerParticipant(_maxPartitionsPerParticipant);
+      context.setReplicaCount(_replicaCount);
+    }
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerConfig.java
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diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerConfig.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerConfig.java
new file mode 100644
index 0000000..846fd01
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerConfig.java
@@ -0,0 +1,178 @@
+package org.apache.helix.controller.rebalancer.context;
+
+import org.apache.helix.api.Scope;
+import org.apache.helix.api.config.NamespacedConfig;
+import org.apache.helix.controller.rebalancer.Rebalancer;
+import org.apache.helix.model.ResourceConfiguration;
+import org.apache.helix.util.HelixUtil;
+import org.apache.log4j.Logger;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Configuration for a resource rebalancer. This contains a RebalancerContext, which contains
+ * information specific to each rebalancer.
+ */
+public final class RebalancerConfig {
+  private enum Fields {
+    SERIALIZER_CLASS,
+    REBALANCER_CONTEXT,
+    REBALANCER_CONTEXT_CLASS
+  }
+
+  private static final Logger LOG = Logger.getLogger(RebalancerConfig.class);
+  private ContextSerializer _serializer;
+  private Rebalancer _rebalancer;
+  private final RebalancerContext _context;
+  private final NamespacedConfig _config;
+
+  /**
+   * Instantiate a RebalancerConfig
+   * @param context rebalancer context
+   * @param rebalancerRef reference to the rebalancer class that will be used
+   */
+  public RebalancerConfig(RebalancerContext context) {
+    _config =
+        new NamespacedConfig(Scope.resource(context.getResourceId()),
+            RebalancerConfig.class.getSimpleName());
+    _config.setSimpleField(Fields.SERIALIZER_CLASS.toString(), context.getSerializerClass()
+        .getName());
+    _config
+        .setSimpleField(Fields.REBALANCER_CONTEXT_CLASS.toString(), context.getClass().getName());
+    _context = context;
+    try {
+      _serializer = context.getSerializerClass().newInstance();
+      _config.setSimpleField(Fields.REBALANCER_CONTEXT.toString(), _serializer.serialize(context));
+    } catch (InstantiationException e) {
+      LOG.error("Error initializing the configuration", e);
+    } catch (IllegalAccessException e) {
+      LOG.error("Error initializing the configuration", e);
+    }
+  }
+
+  /**
+   * Instantiate from a physical ResourceConfiguration
+   * @param resourceConfiguration populated ResourceConfiguration
+   */
+  public RebalancerConfig(ResourceConfiguration resourceConfiguration) {
+    _config = new NamespacedConfig(resourceConfiguration, RebalancerConfig.class.getSimpleName());
+    _serializer = getSerializer();
+    _context = getContext();
+  }
+
+  /**
+   * Get the class that can serialize and deserialize the rebalancer context
+   * @return ContextSerializer
+   */
+  private ContextSerializer getSerializer() {
+    String serializerClassName = _config.getSimpleField(Fields.SERIALIZER_CLASS.toString());
+    if (serializerClassName != null) {
+      try {
+        return (ContextSerializer) HelixUtil.loadClass(getClass(), serializerClassName)
+            .newInstance();
+      } catch (InstantiationException e) {
+        LOG.error("Error getting the serializer", e);
+      } catch (IllegalAccessException e) {
+        LOG.error("Error getting the serializer", e);
+      } catch (ClassNotFoundException e) {
+        LOG.error("Error getting the serializer", e);
+      }
+    }
+    return null;
+  }
+
+  private RebalancerContext getContext() {
+    String className = _config.getSimpleField(Fields.REBALANCER_CONTEXT_CLASS.toString());
+    try {
+      Class<? extends RebalancerContext> contextClass =
+          HelixUtil.loadClass(getClass(), className).asSubclass(RebalancerContext.class);
+      String serialized = _config.getSimpleField(Fields.REBALANCER_CONTEXT.toString());
+      return _serializer.deserialize(contextClass, serialized);
+    } catch (ClassNotFoundException e) {
+      LOG.error(className + " is not a valid class");
+    } catch (ClassCastException e) {
+      LOG.error(className + " does not implement RebalancerContext");
+    }
+    return null;
+  }
+
+  /**
+   * Get a rebalancer class instance
+   * @return Rebalancer
+   */
+  public Rebalancer getRebalancer() {
+    // cache the rebalancer to avoid loading and instantiating it excessively
+    if (_rebalancer == null) {
+      if (_context == null || _context.getRebalancerRef() == null) {
+        return null;
+      }
+      _rebalancer = _context.getRebalancerRef().getRebalancer();
+    }
+    return _rebalancer;
+  }
+
+  /**
+   * Get the instantiated RebalancerContext
+   * @param contextClass specific class of the RebalancerContext
+   * @return RebalancerContext subclass instance, or null if conversion is not possible
+   */
+  public <T extends RebalancerContext> T getRebalancerContext(Class<T> contextClass) {
+    try {
+      return contextClass.cast(_context);
+    } catch (ClassCastException e) {
+      LOG.info(contextClass + " is incompatible with context class: " + _context.getClass());
+    }
+    return null;
+  }
+
+  /**
+   * Get the rebalancer context serialized as a string
+   * @return string representing the context
+   */
+  public String getSerializedContext() {
+    return _config.getSimpleField(Fields.REBALANCER_CONTEXT.toString());
+  }
+
+  /**
+   * Convert this to a namespaced config
+   * @return NamespacedConfig
+   */
+  public NamespacedConfig toNamespacedConfig() {
+    return _config;
+  }
+
+  /**
+   * Get a RebalancerConfig from a physical resource config
+   * @param resourceConfiguration physical resource config
+   * @return RebalancerConfig
+   */
+  public static RebalancerConfig from(ResourceConfiguration resourceConfiguration) {
+    return new RebalancerConfig(resourceConfiguration);
+  }
+
+  /**
+   * Get a RebalancerConfig from a RebalancerContext
+   * @param context instantiated RebalancerContext
+   * @return RebalancerConfig
+   */
+  public static RebalancerConfig from(RebalancerContext context) {
+    return new RebalancerConfig(context);
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerContext.java
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diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerContext.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerContext.java
new file mode 100644
index 0000000..981891b
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/RebalancerContext.java
@@ -0,0 +1,94 @@
+package org.apache.helix.controller.rebalancer.context;
+
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.api.Partition;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.api.id.StateModelDefId;
+import org.apache.helix.api.id.StateModelFactoryId;
+import org.apache.helix.controller.rebalancer.RebalancerRef;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Defines the state available to a rebalancer. The most common use case is to use a
+ * {@link PartitionedRebalancerContext} or a subclass and set up a resource with it. A rebalancer
+ * configuration, at a minimum, is aware of subunits of a resource, the state model to follow, and
+ * how the configuration should be serialized.
+ */
+public interface RebalancerContext {
+  /**
+   * Get a map of resource partition identifiers to partitions. A partition is a subunit of a
+   * resource, e.g. a subtask of a task
+   * @return map of (subunit id, subunit) pairs
+   */
+  public Map<? extends PartitionId, ? extends Partition> getSubUnitMap();
+
+  /**
+   * Get the subunits of the resource (e.g. partitions)
+   * @return set of subunit ids
+   */
+  public Set<? extends PartitionId> getSubUnitIdSet();
+
+  /**
+   * Get a specific subunit
+   * @param subUnitId the id of the subunit
+   * @return SubUnit
+   */
+  public Partition getSubUnit(PartitionId subUnitId);
+
+  /**
+   * Get the resource to rebalance
+   * @return resource id
+   */
+  public ResourceId getResourceId();
+
+  /**
+   * Get the state model definition that the resource follows
+   * @return state model definition id
+   */
+  public StateModelDefId getStateModelDefId();
+
+  /**
+   * Get the state model factory of this resource
+   * @return state model factory id
+   */
+  public StateModelFactoryId getStateModelFactoryId();
+
+  /**
+   * Get the tag, if any, that participants must have in order to serve this resource
+   * @return participant group tag, or null
+   */
+  public String getParticipantGroupTag();
+
+  /**
+   * Get the serializer for this context
+   * @return ContextSerializer class object
+   */
+  public Class<? extends ContextSerializer> getSerializerClass();
+
+  /**
+   * Get a reference to the class used to rebalance this resource
+   * @return RebalancerRef
+   */
+  public RebalancerRef getRebalancerRef();
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/ReplicatedRebalancerContext.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/ReplicatedRebalancerContext.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/ReplicatedRebalancerContext.java
new file mode 100644
index 0000000..525931d
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/ReplicatedRebalancerContext.java
@@ -0,0 +1,40 @@
+package org.apache.helix.controller.rebalancer.context;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Methods specifying a rebalancer context that allows replicas. For instance, a rebalancer context
+ * with partitions may accept state model definitions that support multiple replicas per partition,
+ * and it's possible that the policy is that each live participant in the system should have a
+ * replica.
+ */
+public interface ReplicatedRebalancerContext extends RebalancerContext {
+  /**
+   * Check if this resource should be assigned to any live participant
+   * @return true if any live participant expected, false otherwise
+   */
+  public boolean anyLiveParticipant();
+
+  /**
+   * Get the number of replicas that each resource subunit should have
+   * @return replica count
+   */
+  public int getReplicaCount();
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/SemiAutoRebalancerContext.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/SemiAutoRebalancerContext.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/SemiAutoRebalancerContext.java
new file mode 100644
index 0000000..f574a62
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/context/SemiAutoRebalancerContext.java
@@ -0,0 +1,178 @@
+package org.apache.helix.controller.rebalancer.context;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.api.State;
+import org.apache.helix.api.id.ParticipantId;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.controller.rebalancer.RebalancerRef;
+import org.apache.helix.controller.rebalancer.SemiAutoRebalancer;
+import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy.DefaultPlacementScheme;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy.ReplicaPlacementScheme;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.IdealState.RebalanceMode;
+import org.apache.helix.model.StateModelDefinition;
+import org.codehaus.jackson.annotate.JsonIgnore;
+import org.codehaus.jackson.annotate.JsonProperty;
+
+import com.google.common.collect.Maps;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * RebalancerContext for SEMI_AUTO rebalancer mode. It indicates the preferred locations of each
+ * partition replica. By default, it corresponds to {@link SemiAutoRebalancer}
+ */
+public final class SemiAutoRebalancerContext extends PartitionedRebalancerContext {
+  @JsonProperty("preferenceLists")
+  private Map<PartitionId, List<ParticipantId>> _preferenceLists;
+
+  /**
+   * Instantiate a SemiAutoRebalancerContext
+   */
+  public SemiAutoRebalancerContext() {
+    super(RebalanceMode.SEMI_AUTO);
+    setRebalancerRef(RebalancerRef.from(SemiAutoRebalancer.class));
+    _preferenceLists = Maps.newHashMap();
+  }
+
+  /**
+   * Get the preference lists of all partitions of the resource
+   * @return map of partition id to list of participant ids
+   */
+  public Map<PartitionId, List<ParticipantId>> getPreferenceLists() {
+    return _preferenceLists;
+  }
+
+  /**
+   * Set the preference lists of all partitions of the resource
+   * @param preferenceLists
+   */
+  public void setPreferenceLists(Map<PartitionId, List<ParticipantId>> preferenceLists) {
+    _preferenceLists = preferenceLists;
+  }
+
+  /**
+   * Get the preference list of a partition
+   * @param partitionId the partition to look up
+   * @return list of participant ids
+   */
+  @JsonIgnore
+  public List<ParticipantId> getPreferenceList(PartitionId partitionId) {
+    return _preferenceLists.get(partitionId);
+  }
+
+  /**
+   * Generate preference lists based on a default cluster setup
+   * @param stateModelDef the state model definition to follow
+   * @param participantSet the set of participant ids to configure for
+   */
+  @Override
+  @JsonIgnore
+  public void generateDefaultConfiguration(StateModelDefinition stateModelDef,
+      Set<ParticipantId> participantSet) {
+    // compute default upper bounds
+    Map<State, String> upperBounds = Maps.newHashMap();
+    for (State state : stateModelDef.getTypedStatesPriorityList()) {
+      upperBounds.put(state, stateModelDef.getNumParticipantsPerState(state));
+    }
+
+    // determine the current mapping
+    Map<PartitionId, Map<ParticipantId, State>> currentMapping = Maps.newHashMap();
+    for (PartitionId partitionId : getPartitionSet()) {
+      List<ParticipantId> preferenceList = getPreferenceList(partitionId);
+      if (preferenceList != null && !preferenceList.isEmpty()) {
+        Set<ParticipantId> disabledParticipants = Collections.emptySet();
+        Map<ParticipantId, State> emptyCurrentState = Collections.emptyMap();
+        Map<ParticipantId, State> initialMap =
+            ConstraintBasedAssignment.computeAutoBestStateForPartition(upperBounds,
+                participantSet, stateModelDef, preferenceList, emptyCurrentState,
+                disabledParticipants);
+        currentMapping.put(partitionId, initialMap);
+      }
+    }
+
+    // determine the preference
+    LinkedHashMap<State, Integer> stateCounts =
+        ConstraintBasedAssignment.stateCount(upperBounds, stateModelDef, participantSet.size(),
+            getReplicaCount());
+    ReplicaPlacementScheme placementScheme = new DefaultPlacementScheme();
+    List<ParticipantId> participantList = new ArrayList<ParticipantId>(participantSet);
+    List<PartitionId> partitionList = new ArrayList<PartitionId>(getPartitionSet());
+    AutoRebalanceStrategy strategy =
+        new AutoRebalanceStrategy(ResourceId.from(""), partitionList, stateCounts,
+            getMaxPartitionsPerParticipant(), placementScheme);
+    Map<String, List<String>> rawPreferenceLists =
+        strategy.typedComputePartitionAssignment(participantList, currentMapping, participantList)
+            .getListFields();
+    Map<PartitionId, List<ParticipantId>> preferenceLists =
+        Maps.newHashMap(IdealState.preferenceListsFromStringLists(rawPreferenceLists));
+    setPreferenceLists(preferenceLists);
+  }
+
+  /**
+   * Build a SemiAutoRebalancerContext. By default, it corresponds to {@link SemiAutoRebalancer}
+   */
+  public static final class Builder extends PartitionedRebalancerContext.AbstractBuilder<Builder> {
+    private final Map<PartitionId, List<ParticipantId>> _preferenceLists;
+
+    /**
+     * Instantiate for a resource
+     * @param resourceId resource id
+     */
+    public Builder(ResourceId resourceId) {
+      super(resourceId);
+      super.rebalancerRef(RebalancerRef.from(SemiAutoRebalancer.class));
+      _preferenceLists = Maps.newHashMap();
+    }
+
+    /**
+     * Add a preference list for a partition
+     * @param partitionId partition to set
+     * @param preferenceList ordered list of participants who can serve the partition
+     * @return Builder
+     */
+    public Builder preferenceList(PartitionId partitionId, List<ParticipantId> preferenceList) {
+      _preferenceLists.put(partitionId, preferenceList);
+      return self();
+    }
+
+    @Override
+    protected Builder self() {
+      return this;
+    }
+
+    @Override
+    public SemiAutoRebalancerContext build() {
+      SemiAutoRebalancerContext context = new SemiAutoRebalancerContext();
+      super.update(context);
+      context.setPreferenceLists(_preferenceLists);
+      return context;
+    }
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/util/ConstraintBasedAssignment.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/util/ConstraintBasedAssignment.java b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/util/ConstraintBasedAssignment.java
index ce52a19..a0ee1c1 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/rebalancer/util/ConstraintBasedAssignment.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/rebalancer/util/ConstraintBasedAssignment.java
@@ -30,89 +30,136 @@ import java.util.Set;
 
 import org.apache.helix.HelixConstants.StateModelToken;
 import org.apache.helix.HelixDefinedState;
-import org.apache.helix.controller.stages.ClusterDataCache;
-import org.apache.helix.model.IdealState;
-import org.apache.helix.model.LiveInstance;
-import org.apache.helix.model.Partition;
+import org.apache.helix.api.Cluster;
+import org.apache.helix.api.Participant;
+import org.apache.helix.api.Scope;
+import org.apache.helix.api.State;
+import org.apache.helix.api.config.ClusterConfig;
+import org.apache.helix.api.id.ParticipantId;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.model.StateModelDefinition;
 import org.apache.log4j.Logger;
 
+import com.google.common.base.Predicate;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
 /**
- * Collection of functions that will compute the best possible states given the live instances and
- * an ideal state.<br/>
- * <br/>
- * Deprecated. Use {@link org.apache.helix.api.rebalancer.util.ConstraintBasedAssignment} instead.
+ * Collection of functions that will compute the best possible state based on the participants and
+ * the rebalancer configuration of a resource.
  */
-@Deprecated
 public class ConstraintBasedAssignment {
   private static Logger logger = Logger.getLogger(ConstraintBasedAssignment.class);
 
-  public static List<String> getPreferenceList(ClusterDataCache cache, Partition resource,
-      IdealState idealState, StateModelDefinition stateModelDef) {
-    List<String> listField = idealState.getPreferenceList(resource.getPartitionName());
+  /**
+   * Get a set of disabled participants for a partition
+   * @param participantMap map of all participants
+   * @param partitionId the partition to check
+   * @return a set of all participants that are disabled for the partition
+   */
+  public static Set<ParticipantId> getDisabledParticipants(
+      final Map<ParticipantId, Participant> participantMap, final PartitionId partitionId) {
+    Set<ParticipantId> participantSet = new HashSet<ParticipantId>(participantMap.keySet());
+    Set<ParticipantId> disabledParticipantsForPartition =
+        Sets.filter(participantSet, new Predicate<ParticipantId>() {
+          @Override
+          public boolean apply(ParticipantId participantId) {
+            Participant participant = participantMap.get(participantId);
+            return !participant.isEnabled()
+                || participant.getDisabledPartitionIds().contains(partitionId);
+          }
+        });
+    return disabledParticipantsForPartition;
+  }
 
-    if (listField != null && listField.size() == 1
-        && StateModelToken.ANY_LIVEINSTANCE.toString().equals(listField.get(0))) {
-      Map<String, LiveInstance> liveInstances = cache.getLiveInstances();
-      List<String> prefList = new ArrayList<String>(liveInstances.keySet());
+  /**
+   * Get an ordered list of participants that can serve a partition
+   * @param cluster cluster snapshot
+   * @param partitionId the partition to look up
+   * @param config rebalancing constraints
+   * @return list with most preferred participants first
+   */
+  public static List<ParticipantId> getPreferenceList(Cluster cluster, PartitionId partitionId,
+      List<ParticipantId> prefList) {
+    if (prefList != null && prefList.size() == 1
+        && StateModelToken.ANY_LIVEINSTANCE.toString().equals(prefList.get(0).stringify())) {
+      prefList = new ArrayList<ParticipantId>(cluster.getLiveParticipantMap().keySet());
       Collections.sort(prefList);
-      return prefList;
-    } else {
-      return listField;
     }
+    return prefList;
   }
 
   /**
-   * compute best state for resource in AUTO ideal state mode
-   * @param cache
+   * Get a map of state to upper bound constraint given a cluster
+   * @param stateModelDef the state model definition to check
+   * @param resourceId the resource that is constraint
+   * @param cluster the cluster the resource belongs to
+   * @return map of state to upper bound
+   */
+  public static Map<State, String> stateConstraints(StateModelDefinition stateModelDef,
+      ResourceId resourceId, ClusterConfig cluster) {
+    Map<State, String> stateMap = Maps.newHashMap();
+    for (State state : stateModelDef.getTypedStatesPriorityList()) {
+      String num =
+          cluster.getStateUpperBoundConstraint(Scope.resource(resourceId),
+              stateModelDef.getStateModelDefId(), state);
+      stateMap.put(state, num);
+    }
+    return stateMap;
+  }
+
+  /**
+   * compute best state for resource in SEMI_AUTO and FULL_AUTO modes
+   * @param upperBounds map of state to upper bound
+   * @param liveParticipantSet set of live participant ids
    * @param stateModelDef
-   * @param instancePreferenceList
+   * @param participantPreferenceList
    * @param currentStateMap
-   *          : instance->state for each partition
-   * @param disabledInstancesForPartition
+   *          : participant->state for each partition
+   * @param disabledParticipantsForPartition
    * @return
    */
-  public static Map<String, String> computeAutoBestStateForPartition(ClusterDataCache cache,
-      StateModelDefinition stateModelDef, List<String> instancePreferenceList,
-      Map<String, String> currentStateMap, Set<String> disabledInstancesForPartition) {
-    Map<String, String> instanceStateMap = new HashMap<String, String>();
+  public static Map<ParticipantId, State> computeAutoBestStateForPartition(
+      Map<State, String> upperBounds, Set<ParticipantId> liveParticipantSet,
+      StateModelDefinition stateModelDef, List<ParticipantId> participantPreferenceList,
+      Map<ParticipantId, State> currentStateMap, Set<ParticipantId> disabledParticipantsForPartition) {
+    Map<ParticipantId, State> participantStateMap = new HashMap<ParticipantId, State>();
 
-    // if the ideal state is deleted, instancePreferenceList will be empty and
+    // if the resource is deleted, instancePreferenceList will be empty and
     // we should drop all resources.
     if (currentStateMap != null) {
-      for (String instance : currentStateMap.keySet()) {
-        if ((instancePreferenceList == null || !instancePreferenceList.contains(instance))
-            && !disabledInstancesForPartition.contains(instance)) {
+      for (ParticipantId participantId : currentStateMap.keySet()) {
+        if ((participantPreferenceList == null || !participantPreferenceList
+            .contains(participantId)) && !disabledParticipantsForPartition.contains(participantId)) {
           // if dropped and not disabled, transit to DROPPED
-          instanceStateMap.put(instance, HelixDefinedState.DROPPED.toString());
-        } else if ((currentStateMap.get(instance) == null || !currentStateMap.get(instance).equals(
-            HelixDefinedState.ERROR.toString()))
-            && disabledInstancesForPartition.contains(instance)) {
+          participantStateMap.put(participantId, State.from(HelixDefinedState.DROPPED));
+        } else if ((currentStateMap.get(participantId) == null || !currentStateMap.get(
+            participantId).equals(State.from(HelixDefinedState.ERROR)))
+            && disabledParticipantsForPartition.contains(participantId)) {
           // if disabled and not in ERROR state, transit to initial-state (e.g. OFFLINE)
-          instanceStateMap.put(instance, stateModelDef.getInitialState());
+          participantStateMap.put(participantId, stateModelDef.getTypedInitialState());
         }
       }
     }
 
-    // ideal state is deleted
-    if (instancePreferenceList == null) {
-      return instanceStateMap;
+    // resource is deleted
+    if (participantPreferenceList == null) {
+      return participantStateMap;
     }
 
-    List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
-    boolean assigned[] = new boolean[instancePreferenceList.size()];
-
-    Map<String, LiveInstance> liveInstancesMap = cache.getLiveInstances();
+    List<State> statesPriorityList = stateModelDef.getTypedStatesPriorityList();
+    boolean assigned[] = new boolean[participantPreferenceList.size()];
 
-    for (String state : statesPriorityList) {
-      String num = stateModelDef.getNumInstancesPerState(state);
+    for (State state : statesPriorityList) {
+      String num = upperBounds.get(state);
       int stateCount = -1;
       if ("N".equals(num)) {
-        Set<String> liveAndEnabled = new HashSet<String>(liveInstancesMap.keySet());
-        liveAndEnabled.removeAll(disabledInstancesForPartition);
+        Set<ParticipantId> liveAndEnabled = new HashSet<ParticipantId>(liveParticipantSet);
+        liveAndEnabled.removeAll(disabledParticipantsForPartition);
         stateCount = liveAndEnabled.size();
       } else if ("R".equals(num)) {
-        stateCount = instancePreferenceList.size();
+        stateCount = participantPreferenceList.size();
       } else {
         try {
           stateCount = Integer.parseInt(num);
@@ -122,16 +169,18 @@ public class ConstraintBasedAssignment {
       }
       if (stateCount > -1) {
         int count = 0;
-        for (int i = 0; i < instancePreferenceList.size(); i++) {
-          String instanceName = instancePreferenceList.get(i);
+        for (int i = 0; i < participantPreferenceList.size(); i++) {
+          ParticipantId participantId = participantPreferenceList.get(i);
 
           boolean notInErrorState =
-              currentStateMap == null || currentStateMap.get(instanceName) == null
-                  || !currentStateMap.get(instanceName).equals(HelixDefinedState.ERROR.toString());
-
-          if (liveInstancesMap.containsKey(instanceName) && !assigned[i] && notInErrorState
-              && !disabledInstancesForPartition.contains(instanceName)) {
-            instanceStateMap.put(instanceName, state);
+              currentStateMap == null
+                  || currentStateMap.get(participantId) == null
+                  || !currentStateMap.get(participantId)
+                      .equals(State.from(HelixDefinedState.ERROR));
+
+          if (liveParticipantSet.contains(participantId) && !assigned[i] && notInErrorState
+              && !disabledParticipantsForPartition.contains(participantId)) {
+            participantStateMap.put(participantId, state);
             count = count + 1;
             assigned[i] = true;
             if (count == stateCount) {
@@ -141,24 +190,25 @@ public class ConstraintBasedAssignment {
         }
       }
     }
-    return instanceStateMap;
+    return participantStateMap;
   }
 
   /**
    * Get the number of replicas that should be in each state for a partition
+   * @param upperBounds map of state to upper bound
    * @param stateModelDef StateModelDefinition object
    * @param liveNodesNb number of live nodes
    * @param total number of replicas
    * @return state count map: state->count
    */
-  public static LinkedHashMap<String, Integer> stateCount(StateModelDefinition stateModelDef,
-      int liveNodesNb, int totalReplicas) {
-    LinkedHashMap<String, Integer> stateCountMap = new LinkedHashMap<String, Integer>();
-    List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
+  public static LinkedHashMap<State, Integer> stateCount(Map<State, String> upperBounds,
+      StateModelDefinition stateModelDef, int liveNodesNb, int totalReplicas) {
+    LinkedHashMap<State, Integer> stateCountMap = new LinkedHashMap<State, Integer>();
+    List<State> statesPriorityList = stateModelDef.getTypedStatesPriorityList();
 
     int replicas = totalReplicas;
-    for (String state : statesPriorityList) {
-      String num = stateModelDef.getNumInstancesPerState(state);
+    for (State state : statesPriorityList) {
+      String num = upperBounds.get(state);
       if ("N".equals(num)) {
         stateCountMap.put(state, liveNodesNb);
       } else if ("R".equals(num)) {
@@ -181,8 +231,8 @@ public class ConstraintBasedAssignment {
     }
 
     // get state count for R
-    for (String state : statesPriorityList) {
-      String num = stateModelDef.getNumInstancesPerState(state);
+    for (State state : statesPriorityList) {
+      String num = upperBounds.get(state);
       if ("R".equals(num)) {
         stateCountMap.put(state, replicas);
         // should have at most one state using R

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java
index 51301f0..aae33b4 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/BestPossibleStateCalcStage.java
@@ -30,12 +30,12 @@ import org.apache.helix.api.id.ParticipantId;
 import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelDefId;
-import org.apache.helix.api.rebalancer.Rebalancer;
-import org.apache.helix.api.rebalancer.RebalancerConfig;
-import org.apache.helix.api.rebalancer.RebalancerContext;
-import org.apache.helix.api.rebalancer.util.ConstraintBasedAssignment;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
 import org.apache.helix.controller.pipeline.StageException;
+import org.apache.helix.controller.rebalancer.Rebalancer;
+import org.apache.helix.controller.rebalancer.context.RebalancerConfig;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
+import org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment;
 import org.apache.helix.model.ResourceAssignment;
 import org.apache.helix.model.StateModelDefinition;
 import org.apache.log4j.Logger;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/ExternalViewComputeStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/ExternalViewComputeStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/ExternalViewComputeStage.java
index 5ecbddf..1d287fa 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/ExternalViewComputeStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/ExternalViewComputeStage.java
@@ -42,10 +42,10 @@ import org.apache.helix.api.id.ParticipantId;
 import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelDefId;
-import org.apache.helix.api.rebalancer.RebalancerConfig;
-import org.apache.helix.api.rebalancer.RebalancerContext;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
 import org.apache.helix.controller.pipeline.StageException;
+import org.apache.helix.controller.rebalancer.context.RebalancerConfig;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
 import org.apache.helix.model.ExternalView;
 import org.apache.helix.model.IdealState;
 import org.apache.helix.model.Message;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationStage.java
index 5d9746b..d6fe8c3 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/MessageGenerationStage.java
@@ -37,9 +37,9 @@ import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.SessionId;
 import org.apache.helix.api.id.StateModelDefId;
 import org.apache.helix.api.id.StateModelFactoryId;
-import org.apache.helix.api.rebalancer.RebalancerContext;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
 import org.apache.helix.controller.pipeline.StageException;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
 import org.apache.helix.model.Message;
 import org.apache.helix.model.Message.MessageState;
 import org.apache.helix.model.Message.MessageType;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageSelectionStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageSelectionStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/MessageSelectionStage.java
index 15004a6..5c24314 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/MessageSelectionStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/MessageSelectionStage.java
@@ -36,11 +36,11 @@ import org.apache.helix.api.id.ParticipantId;
 import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelDefId;
-import org.apache.helix.api.rebalancer.RebalancerConfig;
-import org.apache.helix.api.rebalancer.RebalancerContext;
-import org.apache.helix.api.rebalancer.ReplicatedRebalancerContext;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
 import org.apache.helix.controller.pipeline.StageException;
+import org.apache.helix.controller.rebalancer.context.RebalancerConfig;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
+import org.apache.helix.controller.rebalancer.context.ReplicatedRebalancerContext;
 import org.apache.helix.model.Message;
 import org.apache.helix.model.StateModelDefinition;
 import org.apache.log4j.Logger;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/RebalanceIdealStateStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/RebalanceIdealStateStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/RebalanceIdealStateStage.java
index 949cfca..a9ab34e 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/RebalanceIdealStateStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/RebalanceIdealStateStage.java
@@ -24,7 +24,7 @@ import java.util.Map;
 
 import org.apache.helix.HelixManager;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
-import org.apache.helix.controller.rebalancer.Rebalancer;
+import org.apache.helix.deprecated.controller.rebalancer.Rebalancer;
 import org.apache.helix.model.IdealState;
 import org.apache.helix.model.IdealState.RebalanceMode;
 import org.apache.helix.model.Resource;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/controller/stages/ResourceComputationStage.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/controller/stages/ResourceComputationStage.java b/helix-core/src/main/java/org/apache/helix/controller/stages/ResourceComputationStage.java
index dc56b89..1fdd892 100644
--- a/helix-core/src/main/java/org/apache/helix/controller/stages/ResourceComputationStage.java
+++ b/helix-core/src/main/java/org/apache/helix/controller/stages/ResourceComputationStage.java
@@ -30,11 +30,11 @@ import org.apache.helix.api.config.ResourceConfig;
 import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelFactoryId;
-import org.apache.helix.api.rebalancer.PartitionedRebalancerContext;
-import org.apache.helix.api.rebalancer.RebalancerConfig;
-import org.apache.helix.api.rebalancer.RebalancerContext;
 import org.apache.helix.controller.pipeline.AbstractBaseStage;
 import org.apache.helix.controller.pipeline.StageException;
+import org.apache.helix.controller.rebalancer.context.PartitionedRebalancerContext;
+import org.apache.helix.controller.rebalancer.context.RebalancerConfig;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
 import org.apache.helix.model.CurrentState;
 import org.apache.log4j.Logger;
 

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/AutoRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/AutoRebalancer.java b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/AutoRebalancer.java
new file mode 100644
index 0000000..afe132e
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/AutoRebalancer.java
@@ -0,0 +1,187 @@
+package org.apache.helix.deprecated.controller.rebalancer;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.HelixManager;
+import org.apache.helix.ZNRecord;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.controller.stages.CurrentStateOutput;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy.DefaultPlacementScheme;
+import org.apache.helix.controller.strategy.AutoRebalanceStrategy.ReplicaPlacementScheme;
+import org.apache.helix.deprecated.controller.rebalancer.util.ConstraintBasedAssignment;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.IdealState.RebalanceMode;
+import org.apache.helix.model.LiveInstance;
+import org.apache.helix.model.Partition;
+import org.apache.helix.model.Resource;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.log4j.Logger;
+
+/**
+ * This is a Rebalancer specific to full automatic mode. It is tasked with computing the ideal
+ * state of a resource, fully adapting to the addition or removal of instances. This includes
+ * computation of a new preference list and a partition to instance and state mapping based on the
+ * computed instance preferences.
+ * The input is the current assignment of partitions to instances, as well as existing instance
+ * preferences, if any.
+ * The output is a preference list and a mapping based on that preference list, i.e. partition p
+ * has a replica on node k with state s.
+ */
+@Deprecated
+public class AutoRebalancer implements Rebalancer {
+  // These should be final, but are initialized in init rather than a constructor
+  private HelixManager _manager;
+  private AutoRebalanceStrategy _algorithm;
+
+  private static final Logger LOG = Logger.getLogger(AutoRebalancer.class);
+
+  @Override
+  public void init(HelixManager manager) {
+    this._manager = manager;
+    this._algorithm = null;
+  }
+
+  @Override
+  public ResourceAssignment computeResourceMapping(Resource resource, IdealState currentIdealState,
+      CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
+    // Compute a preference list based on the current ideal state
+    List<String> partitions = new ArrayList<String>(currentIdealState.getPartitionSet());
+    String stateModelName = currentIdealState.getStateModelDefRef();
+    StateModelDefinition stateModelDef = clusterData.getStateModelDef(stateModelName);
+    Map<String, LiveInstance> liveInstance = clusterData.getLiveInstances();
+    String replicas = currentIdealState.getReplicas();
+
+    LinkedHashMap<String, Integer> stateCountMap = new LinkedHashMap<String, Integer>();
+    stateCountMap =
+        ConstraintBasedAssignment.stateCount(stateModelDef, liveInstance.size(),
+            Integer.parseInt(replicas));
+    List<String> liveNodes = new ArrayList<String>(liveInstance.keySet());
+    Map<String, Map<String, String>> currentMapping =
+        currentMapping(currentStateOutput, resource.getResourceName(), partitions, stateCountMap);
+
+    // If there are nodes tagged with resource name, use only those nodes
+    Set<String> taggedNodes = new HashSet<String>();
+    if (currentIdealState.getInstanceGroupTag() != null) {
+      for (String instanceName : liveNodes) {
+        if (clusterData.getInstanceConfigMap().get(instanceName)
+            .containsTag(currentIdealState.getInstanceGroupTag())) {
+          taggedNodes.add(instanceName);
+        }
+      }
+    }
+    if (taggedNodes.size() > 0) {
+      if (LOG.isInfoEnabled()) {
+        LOG.info("found the following instances with tag " + currentIdealState.getResourceName()
+            + " " + taggedNodes);
+      }
+      liveNodes = new ArrayList<String>(taggedNodes);
+    }
+
+    List<String> allNodes = new ArrayList<String>(clusterData.getInstanceConfigMap().keySet());
+    int maxPartition = currentIdealState.getMaxPartitionsPerInstance();
+
+    if (LOG.isInfoEnabled()) {
+      LOG.info("currentMapping: " + currentMapping);
+      LOG.info("stateCountMap: " + stateCountMap);
+      LOG.info("liveNodes: " + liveNodes);
+      LOG.info("allNodes: " + allNodes);
+      LOG.info("maxPartition: " + maxPartition);
+    }
+    ReplicaPlacementScheme placementScheme = new DefaultPlacementScheme();
+    placementScheme.init(_manager);
+    _algorithm =
+        new AutoRebalanceStrategy(resource.getResourceName(), partitions, stateCountMap,
+            maxPartition, placementScheme);
+    ZNRecord newMapping =
+        _algorithm.computePartitionAssignment(liveNodes, currentMapping, allNodes);
+
+    if (LOG.isInfoEnabled()) {
+      LOG.info("newMapping: " + newMapping);
+    }
+
+    IdealState newIdealState = new IdealState(resource.getResourceName());
+    newIdealState.getRecord().setSimpleFields(currentIdealState.getRecord().getSimpleFields());
+    newIdealState.setRebalanceMode(RebalanceMode.FULL_AUTO);
+    newIdealState.getRecord().setListFields(newMapping.getListFields());
+
+    // compute a full partition mapping for the resource
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Processing resource:" + resource.getResourceName());
+    }
+    ResourceAssignment partitionMapping =
+        new ResourceAssignment(ResourceId.from(resource.getResourceName()));
+    for (String partitionName : partitions) {
+      Partition partition = new Partition(partitionName);
+      Map<String, String> currentStateMap =
+          currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
+      Set<String> disabledInstancesForPartition =
+          clusterData.getDisabledInstancesForPartition(partition.toString());
+      List<String> preferenceList =
+          ConstraintBasedAssignment.getPreferenceList(clusterData, partition, newIdealState,
+              stateModelDef);
+      Map<String, String> bestStateForPartition =
+          ConstraintBasedAssignment.computeAutoBestStateForPartition(clusterData, stateModelDef,
+              preferenceList, currentStateMap, disabledInstancesForPartition);
+      partitionMapping.addReplicaMap(PartitionId.from(partitionName),
+          ResourceAssignment.replicaMapFromStringMap(bestStateForPartition));
+    }
+    return partitionMapping;
+  }
+
+  private Map<String, Map<String, String>> currentMapping(CurrentStateOutput currentStateOutput,
+      String resourceName, List<String> partitions, Map<String, Integer> stateCountMap) {
+
+    Map<String, Map<String, String>> map = new HashMap<String, Map<String, String>>();
+
+    for (String partition : partitions) {
+      Map<String, String> curStateMap =
+          currentStateOutput.getCurrentStateMap(resourceName, new Partition(partition));
+      map.put(partition, new HashMap<String, String>());
+      for (String node : curStateMap.keySet()) {
+        String state = curStateMap.get(node);
+        if (stateCountMap.containsKey(state)) {
+          map.get(partition).put(node, state);
+        }
+      }
+
+      Map<String, String> pendingStateMap =
+          currentStateOutput.getPendingStateMap(resourceName, new Partition(partition));
+      for (String node : pendingStateMap.keySet()) {
+        String state = pendingStateMap.get(node);
+        if (stateCountMap.containsKey(state)) {
+          map.get(partition).put(node, state);
+        }
+      }
+    }
+    return map;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/CustomRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/CustomRebalancer.java b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/CustomRebalancer.java
new file mode 100644
index 0000000..e1136a2
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/CustomRebalancer.java
@@ -0,0 +1,135 @@
+package org.apache.helix.deprecated.controller.rebalancer;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.HelixDefinedState;
+import org.apache.helix.HelixManager;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.controller.stages.CurrentStateOutput;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.LiveInstance;
+import org.apache.helix.model.Partition;
+import org.apache.helix.model.Resource;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.log4j.Logger;
+
+/**
+ * This is a Rebalancer specific to custom mode. It is tasked with checking an existing mapping of
+ * partitions against the set of live instances to mark assignment states as dropped or erroneous
+ * as necessary.
+ * The input is the required current assignment of partitions to instances, as well as the required
+ * existing instance preferences.
+ * The output is a verified mapping based on that preference list, i.e. partition p has a replica
+ * on node k with state s, where s may be a dropped or error state if necessary.
+ */
+@Deprecated
+public class CustomRebalancer implements Rebalancer {
+
+  private static final Logger LOG = Logger.getLogger(CustomRebalancer.class);
+
+  @Override
+  public void init(HelixManager manager) {
+  }
+
+  @Override
+  public ResourceAssignment computeResourceMapping(Resource resource, IdealState currentIdealState,
+      CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
+    String stateModelDefName = currentIdealState.getStateModelDefRef();
+    StateModelDefinition stateModelDef = clusterData.getStateModelDef(stateModelDefName);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Processing resource:" + resource.getResourceName());
+    }
+    ResourceAssignment partitionMapping =
+        new ResourceAssignment(ResourceId.from(resource.getResourceName()));
+    for (Partition partition : resource.getPartitions()) {
+      Map<String, String> currentStateMap =
+          currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
+      Set<String> disabledInstancesForPartition =
+          clusterData.getDisabledInstancesForPartition(partition.toString());
+      Map<String, String> idealStateMap =
+          IdealState.stringMapFromParticipantStateMap(currentIdealState
+              .getParticipantStateMap(PartitionId.from(partition.getPartitionName())));
+      Map<String, String> bestStateForPartition =
+          computeCustomizedBestStateForPartition(clusterData, stateModelDef, idealStateMap,
+              currentStateMap, disabledInstancesForPartition);
+      partitionMapping.addReplicaMap(PartitionId.from(partition.getPartitionName()),
+          ResourceAssignment.replicaMapFromStringMap(bestStateForPartition));
+    }
+    return partitionMapping;
+  }
+
+  /**
+   * compute best state for resource in CUSTOMIZED ideal state mode
+   * @param cache
+   * @param stateModelDef
+   * @param idealStateMap
+   * @param currentStateMap
+   * @param disabledInstancesForPartition
+   * @return
+   */
+  private Map<String, String> computeCustomizedBestStateForPartition(ClusterDataCache cache,
+      StateModelDefinition stateModelDef, Map<String, String> idealStateMap,
+      Map<String, String> currentStateMap, Set<String> disabledInstancesForPartition) {
+    Map<String, String> instanceStateMap = new HashMap<String, String>();
+
+    // if the ideal state is deleted, idealStateMap will be null/empty and
+    // we should drop all resources.
+    if (currentStateMap != null) {
+      for (String instance : currentStateMap.keySet()) {
+        if ((idealStateMap == null || !idealStateMap.containsKey(instance))
+            && !disabledInstancesForPartition.contains(instance)) {
+          // if dropped and not disabled, transit to DROPPED
+          instanceStateMap.put(instance, HelixDefinedState.DROPPED.toString());
+        } else if ((currentStateMap.get(instance) == null || !currentStateMap.get(instance).equals(
+            HelixDefinedState.ERROR.toString()))
+            && disabledInstancesForPartition.contains(instance)) {
+          // if disabled and not in ERROR state, transit to initial-state (e.g. OFFLINE)
+          instanceStateMap.put(instance, stateModelDef.getInitialState());
+        }
+      }
+    }
+
+    // ideal state is deleted
+    if (idealStateMap == null) {
+      return instanceStateMap;
+    }
+
+    Map<String, LiveInstance> liveInstancesMap = cache.getLiveInstances();
+    for (String instance : idealStateMap.keySet()) {
+      boolean notInErrorState =
+          currentStateMap == null || currentStateMap.get(instance) == null
+              || !currentStateMap.get(instance).equals(HelixDefinedState.ERROR.toString());
+
+      if (liveInstancesMap.containsKey(instance) && notInErrorState
+          && !disabledInstancesForPartition.contains(instance)) {
+        instanceStateMap.put(instance, idealStateMap.get(instance));
+      }
+    }
+
+    return instanceStateMap;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/Rebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/Rebalancer.java b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/Rebalancer.java
new file mode 100644
index 0000000..59b827d
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/Rebalancer.java
@@ -0,0 +1,58 @@
+package org.apache.helix.deprecated.controller.rebalancer;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.helix.HelixManager;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.controller.stages.CurrentStateOutput;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.Resource;
+import org.apache.helix.model.ResourceAssignment;
+
+/**
+ * Allows one to come up with custom implementation of a rebalancer.<br/>
+ * This will be invoked on all changes that happen in the cluster.<br/>
+ * Simply return the newIdealState for a resource in this method.<br/>
+ * <br/>
+ * Deprecated. Use {@link org.apache.helix.controller.rebalancer.Rebalancer} instead.
+ */
+@Deprecated
+public interface Rebalancer {
+  /**
+   * Initialize the rebalancer with a HelixManager if necessary
+   * @param manager
+   */
+  void init(HelixManager manager);
+
+  /**
+   * Given an ideal state for a resource and liveness of instances, compute a assignment of
+   * instances and states to each partition of a resource. This method provides all the relevant
+   * information needed to rebalance a resource. If you need additional information use
+   * manager.getAccessor to read the cluster data. This allows one to compute the newIdealState
+   * according to app specific requirements.
+   * @param resourceName the resource for which a mapping will be computed
+   * @param currentIdealState the IdealState that corresponds to this resource
+   * @param currentStateOutput the current states of all partitions
+   * @param clusterData cache of the cluster state
+   */
+  ResourceAssignment computeResourceMapping(final Resource resource,
+      final IdealState currentIdealState, final CurrentStateOutput currentStateOutput,
+      final ClusterDataCache clusterData);
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/SemiAutoRebalancer.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/SemiAutoRebalancer.java b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/SemiAutoRebalancer.java
new file mode 100644
index 0000000..b4259f9
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/SemiAutoRebalancer.java
@@ -0,0 +1,83 @@
+package org.apache.helix.deprecated.controller.rebalancer;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.HelixManager;
+import org.apache.helix.api.id.PartitionId;
+import org.apache.helix.api.id.ResourceId;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.controller.stages.CurrentStateOutput;
+import org.apache.helix.deprecated.controller.rebalancer.util.ConstraintBasedAssignment;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.Partition;
+import org.apache.helix.model.Resource;
+import org.apache.helix.model.ResourceAssignment;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.log4j.Logger;
+
+/**
+ * This is a Rebalancer specific to semi-automatic mode. It is tasked with computing the ideal
+ * state of a resource based on a predefined preference list of instances willing to accept
+ * replicas.
+ * The input is the optional current assignment of partitions to instances, as well as the required
+ * existing instance preferences.
+ * The output is a mapping based on that preference list, i.e. partition p has a replica on node k
+ * with state s.
+ */
+@Deprecated
+public class SemiAutoRebalancer implements Rebalancer {
+
+  private static final Logger LOG = Logger.getLogger(SemiAutoRebalancer.class);
+
+  @Override
+  public void init(HelixManager manager) {
+  }
+
+  @Override
+  public ResourceAssignment computeResourceMapping(Resource resource, IdealState currentIdealState,
+      CurrentStateOutput currentStateOutput, ClusterDataCache clusterData) {
+    String stateModelDefName = currentIdealState.getStateModelDefRef();
+    StateModelDefinition stateModelDef = clusterData.getStateModelDef(stateModelDefName);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Processing resource:" + resource.getResourceName());
+    }
+    ResourceAssignment partitionMapping =
+        new ResourceAssignment(ResourceId.from(resource.getResourceName()));
+    for (Partition partition : resource.getPartitions()) {
+      Map<String, String> currentStateMap =
+          currentStateOutput.getCurrentStateMap(resource.getResourceName(), partition);
+      Set<String> disabledInstancesForPartition =
+          clusterData.getDisabledInstancesForPartition(partition.toString());
+      List<String> preferenceList =
+          ConstraintBasedAssignment.getPreferenceList(clusterData, partition, currentIdealState,
+              stateModelDef);
+      Map<String, String> bestStateForPartition =
+          ConstraintBasedAssignment.computeAutoBestStateForPartition(clusterData, stateModelDef,
+              preferenceList, currentStateMap, disabledInstancesForPartition);
+      partitionMapping.addReplicaMap(PartitionId.from(partition.getPartitionName()),
+          ResourceAssignment.replicaMapFromStringMap(bestStateForPartition));
+    }
+    return partitionMapping;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/util/ConstraintBasedAssignment.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/util/ConstraintBasedAssignment.java b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/util/ConstraintBasedAssignment.java
new file mode 100644
index 0000000..c75423f
--- /dev/null
+++ b/helix-core/src/main/java/org/apache/helix/deprecated/controller/rebalancer/util/ConstraintBasedAssignment.java
@@ -0,0 +1,194 @@
+package org.apache.helix.deprecated.controller.rebalancer.util;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.helix.HelixConstants.StateModelToken;
+import org.apache.helix.HelixDefinedState;
+import org.apache.helix.controller.stages.ClusterDataCache;
+import org.apache.helix.model.IdealState;
+import org.apache.helix.model.LiveInstance;
+import org.apache.helix.model.Partition;
+import org.apache.helix.model.StateModelDefinition;
+import org.apache.log4j.Logger;
+
+/**
+ * Collection of functions that will compute the best possible states given the live instances and
+ * an ideal state.<br/>
+ * <br/>
+ * Deprecated. Use {@link org.apache.helix.controller.rebalancer.util.ConstraintBasedAssignment} instead.
+ */
+@Deprecated
+public class ConstraintBasedAssignment {
+  private static Logger logger = Logger.getLogger(ConstraintBasedAssignment.class);
+
+  public static List<String> getPreferenceList(ClusterDataCache cache, Partition resource,
+      IdealState idealState, StateModelDefinition stateModelDef) {
+    List<String> listField = idealState.getPreferenceList(resource.getPartitionName());
+
+    if (listField != null && listField.size() == 1
+        && StateModelToken.ANY_LIVEINSTANCE.toString().equals(listField.get(0))) {
+      Map<String, LiveInstance> liveInstances = cache.getLiveInstances();
+      List<String> prefList = new ArrayList<String>(liveInstances.keySet());
+      Collections.sort(prefList);
+      return prefList;
+    } else {
+      return listField;
+    }
+  }
+
+  /**
+   * compute best state for resource in AUTO ideal state mode
+   * @param cache
+   * @param stateModelDef
+   * @param instancePreferenceList
+   * @param currentStateMap
+   *          : instance->state for each partition
+   * @param disabledInstancesForPartition
+   * @return
+   */
+  public static Map<String, String> computeAutoBestStateForPartition(ClusterDataCache cache,
+      StateModelDefinition stateModelDef, List<String> instancePreferenceList,
+      Map<String, String> currentStateMap, Set<String> disabledInstancesForPartition) {
+    Map<String, String> instanceStateMap = new HashMap<String, String>();
+
+    // if the ideal state is deleted, instancePreferenceList will be empty and
+    // we should drop all resources.
+    if (currentStateMap != null) {
+      for (String instance : currentStateMap.keySet()) {
+        if ((instancePreferenceList == null || !instancePreferenceList.contains(instance))
+            && !disabledInstancesForPartition.contains(instance)) {
+          // if dropped and not disabled, transit to DROPPED
+          instanceStateMap.put(instance, HelixDefinedState.DROPPED.toString());
+        } else if ((currentStateMap.get(instance) == null || !currentStateMap.get(instance).equals(
+            HelixDefinedState.ERROR.toString()))
+            && disabledInstancesForPartition.contains(instance)) {
+          // if disabled and not in ERROR state, transit to initial-state (e.g. OFFLINE)
+          instanceStateMap.put(instance, stateModelDef.getInitialState());
+        }
+      }
+    }
+
+    // ideal state is deleted
+    if (instancePreferenceList == null) {
+      return instanceStateMap;
+    }
+
+    List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
+    boolean assigned[] = new boolean[instancePreferenceList.size()];
+
+    Map<String, LiveInstance> liveInstancesMap = cache.getLiveInstances();
+
+    for (String state : statesPriorityList) {
+      String num = stateModelDef.getNumInstancesPerState(state);
+      int stateCount = -1;
+      if ("N".equals(num)) {
+        Set<String> liveAndEnabled = new HashSet<String>(liveInstancesMap.keySet());
+        liveAndEnabled.removeAll(disabledInstancesForPartition);
+        stateCount = liveAndEnabled.size();
+      } else if ("R".equals(num)) {
+        stateCount = instancePreferenceList.size();
+      } else {
+        try {
+          stateCount = Integer.parseInt(num);
+        } catch (Exception e) {
+          logger.error("Invalid count for state:" + state + " ,count=" + num);
+        }
+      }
+      if (stateCount > -1) {
+        int count = 0;
+        for (int i = 0; i < instancePreferenceList.size(); i++) {
+          String instanceName = instancePreferenceList.get(i);
+
+          boolean notInErrorState =
+              currentStateMap == null || currentStateMap.get(instanceName) == null
+                  || !currentStateMap.get(instanceName).equals(HelixDefinedState.ERROR.toString());
+
+          if (liveInstancesMap.containsKey(instanceName) && !assigned[i] && notInErrorState
+              && !disabledInstancesForPartition.contains(instanceName)) {
+            instanceStateMap.put(instanceName, state);
+            count = count + 1;
+            assigned[i] = true;
+            if (count == stateCount) {
+              break;
+            }
+          }
+        }
+      }
+    }
+    return instanceStateMap;
+  }
+
+  /**
+   * Get the number of replicas that should be in each state for a partition
+   * @param stateModelDef StateModelDefinition object
+   * @param liveNodesNb number of live nodes
+   * @param total number of replicas
+   * @return state count map: state->count
+   */
+  public static LinkedHashMap<String, Integer> stateCount(StateModelDefinition stateModelDef,
+      int liveNodesNb, int totalReplicas) {
+    LinkedHashMap<String, Integer> stateCountMap = new LinkedHashMap<String, Integer>();
+    List<String> statesPriorityList = stateModelDef.getStatesPriorityList();
+
+    int replicas = totalReplicas;
+    for (String state : statesPriorityList) {
+      String num = stateModelDef.getNumInstancesPerState(state);
+      if ("N".equals(num)) {
+        stateCountMap.put(state, liveNodesNb);
+      } else if ("R".equals(num)) {
+        // wait until we get the counts for all other states
+        continue;
+      } else {
+        int stateCount = -1;
+        try {
+          stateCount = Integer.parseInt(num);
+        } catch (Exception e) {
+          // LOG.error("Invalid count for state: " + state + ", count: " + num +
+          // ", use -1 instead");
+        }
+
+        if (stateCount > 0) {
+          stateCountMap.put(state, stateCount);
+          replicas -= stateCount;
+        }
+      }
+    }
+
+    // get state count for R
+    for (String state : statesPriorityList) {
+      String num = stateModelDef.getNumInstancesPerState(state);
+      if ("R".equals(num)) {
+        stateCountMap.put(state, replicas);
+        // should have at most one state using R
+        break;
+      }
+    }
+    return stateCountMap;
+  }
+}

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/model/IdealState.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/model/IdealState.java b/helix-core/src/main/java/org/apache/helix/model/IdealState.java
index 805f6bf..df4043a 100644
--- a/helix-core/src/main/java/org/apache/helix/model/IdealState.java
+++ b/helix-core/src/main/java/org/apache/helix/model/IdealState.java
@@ -38,7 +38,7 @@ import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelDefId;
 import org.apache.helix.api.id.StateModelFactoryId;
-import org.apache.helix.api.rebalancer.RebalancerRef;
+import org.apache.helix.controller.rebalancer.RebalancerRef;
 import org.apache.log4j.Logger;
 
 import com.google.common.base.Function;

http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/e032132a/helix-core/src/main/java/org/apache/helix/tools/NewClusterSetup.java
----------------------------------------------------------------------
diff --git a/helix-core/src/main/java/org/apache/helix/tools/NewClusterSetup.java b/helix-core/src/main/java/org/apache/helix/tools/NewClusterSetup.java
index f48ebbc..85330be 100644
--- a/helix-core/src/main/java/org/apache/helix/tools/NewClusterSetup.java
+++ b/helix-core/src/main/java/org/apache/helix/tools/NewClusterSetup.java
@@ -45,10 +45,10 @@ import org.apache.helix.api.id.ParticipantId;
 import org.apache.helix.api.id.PartitionId;
 import org.apache.helix.api.id.ResourceId;
 import org.apache.helix.api.id.StateModelDefId;
-import org.apache.helix.api.rebalancer.CustomRebalancerContext;
-import org.apache.helix.api.rebalancer.PartitionedRebalancerContext;
-import org.apache.helix.api.rebalancer.RebalancerContext;
-import org.apache.helix.api.rebalancer.SemiAutoRebalancerContext;
+import org.apache.helix.controller.rebalancer.context.CustomRebalancerContext;
+import org.apache.helix.controller.rebalancer.context.PartitionedRebalancerContext;
+import org.apache.helix.controller.rebalancer.context.RebalancerContext;
+import org.apache.helix.controller.rebalancer.context.SemiAutoRebalancerContext;
 import org.apache.helix.manager.zk.ZKHelixDataAccessor;
 import org.apache.helix.manager.zk.ZNRecordSerializer;
 import org.apache.helix.manager.zk.ZkBaseDataAccessor;


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