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From: bhupeshchawda <git@git.apache.org>
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References: <git-pr-335-apex-malhar@git.apache.org>
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Subject: [GitHub] apex-malhar pull request #335: [Review Only] APEXMALHAR-1701 Deduper with Ma...
Content-Type: text/plain
Message-Id: <20160802120402.918D5E0007@git1-us-west.apache.org>
Date: Tue,  2 Aug 2016 12:04:02 +0000 (UTC)
archived-at: Tue, 02 Aug 2016 12:04:09 -0000

Github user bhupeshchawda commented on a diff in the pull request:

    https://github.com/apache/apex-malhar/pull/335#discussion_r73142080
  
    --- Diff: library/src/main/java/org/apache/apex/malhar/lib/dedup/AbstractDeduper.java ---
    @@ -0,0 +1,459 @@
    +/**
    + * 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.
    + */
    +package org.apache.apex.malhar.lib.dedup;
    +
    +import java.util.Iterator;
    +import java.util.Map;
    +import java.util.Map.Entry;
    +import java.util.concurrent.ExecutionException;
    +import java.util.concurrent.Future;
    +
    +import javax.validation.constraints.NotNull;
    +
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import org.apache.apex.malhar.lib.state.BucketedState;
    +import org.apache.apex.malhar.lib.state.managed.ManagedTimeUnifiedStateImpl;
    +import org.apache.apex.malhar.lib.state.managed.TimeBucketAssigner;
    +import org.apache.hadoop.classification.InterfaceStability.Evolving;
    +
    +import com.google.common.base.Preconditions;
    +import com.google.common.collect.Maps;
    +import com.google.common.util.concurrent.Futures;
    +
    +import com.datatorrent.api.AutoMetric;
    +import com.datatorrent.api.Context;
    +import com.datatorrent.api.Context.OperatorContext;
    +import com.datatorrent.api.DAG;
    +import com.datatorrent.api.DefaultInputPort;
    +import com.datatorrent.api.DefaultOutputPort;
    +import com.datatorrent.api.Operator;
    +import com.datatorrent.api.Operator.ActivationListener;
    +import com.datatorrent.api.annotation.OperatorAnnotation;
    +import com.datatorrent.lib.fileaccess.FileAccessFSImpl;
    +import com.datatorrent.lib.fileaccess.TFileImpl;
    +import com.datatorrent.netlet.util.Slice;
    +
    +/**
    + * Abstract class which allows de-duplicating incoming tuples based on a configured key.
    + * Also supports expiry mechanism based on a configurable expiry period configured using {@link TimeBucketAssigner}
    + * in {@link ManagedTimeUnifiedStateImpl}
    + * Following steps are used in identifying the state of a particular tuple:
    + * 1. Check if the time of the tuple falls in an expired bucket. If so, the tuple is expired
    + * 2. If the tuple is a valid event, it is checked in the store whether the same key already exists in the
    + * time bucket identified by the event time. If, so, the tuple is a duplicate.
    + * 3. Otherwise the tuple is a unique tuple.
    + *
    + * @param <T> type of events
    + */
    +@Evolving
    +@OperatorAnnotation(checkpointableWithinAppWindow = false)
    +public abstract class AbstractDeduper<T>
    +    implements Operator, Operator.IdleTimeHandler, ActivationListener<Context>, Operator.CheckpointNotificationListener
    +{
    +  /**
    +   * The input port on which events are received.
    +   */
    +  public final transient DefaultInputPort<T> input = new DefaultInputPort<T>()
    +  {
    +    @Override
    +    public final void process(T tuple)
    +    {
    +      processTuple(tuple);
    +    }
    +  };
    +
    +  /**
    +   * The output port on which deduped events are emitted.
    +   */
    +  public final transient DefaultOutputPort<T> unique = new DefaultOutputPort<>();
    +
    +  /**
    +   * The output port on which duplicate events are emitted.
    +   */
    +  public final transient DefaultOutputPort<T> duplicate = new DefaultOutputPort<>();
    +
    +  /**
    +   * The output port on which expired events are emitted.
    +   */
    +  public final transient DefaultOutputPort<T> expired = new DefaultOutputPort<>();
    +
    +  /**
    +   * Whether or not the order of tuples be maintained.
    +   * Making this "true" might entail some cost in performance, but makes the operator idempotent.
    +   */
    +  private boolean preserveTupleOrder = true;
    +
    +  @NotNull
    +  protected final ManagedTimeUnifiedStateImpl managedState = new ManagedTimeUnifiedStateImpl();
    +
    +  /**
    +   * Map to hold the result of a tuple processing (unique, duplicate, expired or error) until previous
    +   * tuples get processed. This is used only when {@link #preserveTupleOrder} is true.
    +   */
    +  private transient Map<T, Decision> decisions;
    +  private transient long sleepMillis;
    +  private transient Map<T, Future<Slice>> waitingEvents = Maps.newLinkedHashMap();
    +  private transient Map<Slice, Long> asyncEvents = Maps.newLinkedHashMap();
    +
    +  // Metrics
    +  @AutoMetric
    +  private transient long uniqueEvents;
    +  @AutoMetric
    +  private transient long duplicateEvents;
    +  @AutoMetric
    +  private transient long expiredEvents;
    +
    +  @Override
    +  public void setup(OperatorContext context)
    +  {
    +    sleepMillis = context.getValue(Context.OperatorContext.SPIN_MILLIS);
    +    FileAccessFSImpl fAccessImpl = new TFileImpl.DTFileImpl();
    +    fAccessImpl.setBasePath(context.getValue(DAG.APPLICATION_PATH) + "/bucket_data");
    +    managedState.setFileAccess(fAccessImpl);
    +    managedState.setup(context);
    +
    +    if (preserveTupleOrder) {
    +      decisions = Maps.newLinkedHashMap();
    +    }
    +  }
    +
    +  @Override
    +  public void beginWindow(long l)
    +  {
    +    // Reset Metrics
    +    uniqueEvents = 0;
    +    duplicateEvents = 0;
    +    expiredEvents = 0;
    +
    +    managedState.beginWindow(l);
    +  }
    +
    +  protected abstract Slice getKey(T event);
    +
    +  protected abstract long getTime(T event);
    +
    +  /**
    +   * Processes an incoming tuple
    +   *
    +   * @param tuple
    +   */
    +  protected void processTuple(T tuple)
    +  {
    +
    +    long time = getTime(tuple);
    +    Future<Slice> valFuture = managedState.getAsync(time, getKey(tuple));
    +
    +    if (valFuture.isDone()) {
    +      try {
    +        processEvent(tuple, valFuture.get());
    +      } catch (InterruptedException | ExecutionException e) {
    +        throw new RuntimeException(e);
    +      }
    +    } else {
    +      processWaitingEvent(tuple, valFuture);
    +    }
    +  }
    +
    +  /**
    +   * Processes a looked-up event
    +   *
    +   * @param tuple
    +   * @param value
    +   */
    +  protected void processEvent(T tuple, Slice value)
    +  {
    +    if (value == BucketedState.EXPIRED) {
    +      processInvalid(tuple);
    +      return;
    +    }
    +    processValid(tuple, value);
    +  }
    +
    +  /**
    +   * Processes a tuple which is waiting for the lookup to return.
    +   *
    +   * @param tuple The tuple which needs to wait
    +   * @param future The future object which will ultimately return the lookup result
    +   */
    +  protected void processWaitingEvent(T tuple, Future<Slice> future)
    +  {
    +    waitingEvents.put(tuple, future);
    +    if (preserveTupleOrder) {
    +      recordDecision(tuple, Decision.UNKNOWN);
    +    }
    +  }
    +
    +  /**
    +   * Processes a valid (non-expired) tuple. This tuple may be a unique or a duplicate.
    +   *
    +   * @param tuple
    +   *          The tuple to be processed
    +   * @param value
    +   *          Looked up key of the tuple
    +   */
    +  protected void processValid(T tuple, Slice value)
    +  {
    +    if (!preserveTupleOrder || waitingEvents.isEmpty()) {
    +      if (value == null) {
    +        managedState.put(getTime(tuple), getKey(tuple), getKey(tuple));
    +        processUnique(tuple);
    +      } else {
    +        processDuplicate(tuple);
    +      }
    +    } else {
    +      processWaitingEvent(tuple, Futures.immediateFuture(value));
    +    }
    +  }
    +
    +  /**
    +   * Processes invalid tuples.
    +   *
    +   * @param tuple
    +   */
    +  protected void processInvalid(T tuple)
    +  {
    +    if (preserveTupleOrder && !decisions.isEmpty()) {
    +      recordDecision(tuple, Decision.EXPIRED);
    +    } else {
    +      processExpired(tuple);
    +    }
    +  }
    +
    +  /**
    +   * Processes an expired tuple
    +   *
    +   * @param tuple
    +   */
    +  protected void processExpired(T tuple)
    +  {
    +    expiredEvents++;
    +    emitExpired(tuple);
    +  }
    +
    +  /**
    +   * Processes the duplicate tuple.
    +   *
    +   * @param tuple
    +   *          The tuple which is a duplicate
    +   */
    +  protected void processDuplicate(T tuple)
    +  {
    +    if (preserveTupleOrder && !decisions.isEmpty()) {
    +      recordDecision(tuple, Decision.DUPLICATE);
    +    } else {
    +      duplicateEvents++;
    +      emitDuplicate(tuple);
    +    }
    +  }
    +
    +  /**
    +   * Processes the unique tuple.
    +   *
    +   * @param tuple
    +   *          The tuple which is a unique
    +   */
    +  protected void processUnique(T tuple)
    +  {
    +    if (preserveTupleOrder && !decisions.isEmpty()) {
    +      recordDecision(tuple, Decision.UNIQUE);
    +    } else {
    +      uniqueEvents++;
    +      emitUnique(tuple);
    +    }
    +  }
    +
    +  /**
    +   * {@inheritDoc}
    +   */
    +  @Override
    +  public void handleIdleTime()
    +  {
    +    if (preserveTupleOrder) {
    +      emitProcessedTuples();
    +    }
    +    processAuxiliary(false);
    +  }
    +
    +  /**
    +   * Does any auxiliary processing in the idle time of the operator.
    +   * Processes any tuples which are waiting for the lookup to return.
    +   *
    +   * @param finalize Whether or not to wait for future to return
    +   */
    +  protected void processAuxiliary(boolean finalize)
    +  {
    +    if (waitingEvents.size() > 0) {
    +      Iterator<Map.Entry<T, Future<Slice>>> waitIterator = waitingEvents.entrySet().iterator();
    +      while (waitIterator.hasNext()) {
    +        Map.Entry<T, Future<Slice>> waitingEvent = waitIterator.next();
    +        T tuple = waitingEvent.getKey();
    +        Slice tupleKey = getKey(tuple);
    +        long tupleTime = getTime(tuple);
    +        Future<Slice> future = waitingEvent.getValue();
    +        if (future.isDone() || finalize ) {
    +          try {
    +            if (future.get() == null && asyncEvents.get(tupleKey) == null) {
    +              managedState.put(tupleTime, tupleKey, tupleKey);
    +              asyncEvents.put(tupleKey, tupleTime);
    +              processUnique(tuple);
    +            } else {
    +              processDuplicate(tuple);
    +            }
    +          } catch (InterruptedException | ExecutionException e) {
    +            throw new RuntimeException("handle idle time", e);
    +          }
    +          waitIterator.remove();
    +        }
    +      }
    +    }
    +  }
    +
    +  @Override
    +  public void endWindow()
    +  {
    +    processAuxiliary(true);
    +    if (preserveTupleOrder) {
    +      emitProcessedTuples();
    +    }
    +    Preconditions.checkArgument(waitingEvents.isEmpty());
    +    asyncEvents.clear();
    +    managedState.endWindow();
    +  }
    +
    +  /**
    +   * Records a decision for use later. This is needed to ensure that the order of incoming tuples is maintained.
    +   *
    +   * @param tuple
    +   * @param d The decision for the tuple
    +   */
    +  protected void recordDecision(T tuple, Decision d)
    +  {
    +    decisions.put(tuple, d);
    +  }
    +
    +  /**
    +   * Processes tuples for which the decision (unique / duplicate / expired) has been made.
    +   * Breaks once an undecided tuple is found, as we don't want to emit out of order
    +   */
    +  protected void emitProcessedTuples()
    +  {
    +    Iterator<Entry<T, Decision>> entries = decisions.entrySet().iterator();
    +    while (entries.hasNext()) {
    +      Entry<T, Decision> td = entries.next();
    +      switch (td.getValue()) {
    +        case UNIQUE:
    +          uniqueEvents++;
    +          emitUnique(td.getKey());
    +          entries.remove();
    +          break;
    +        case DUPLICATE:
    +          duplicateEvents++;
    +          emitDuplicate(td.getKey());
    +          entries.remove();
    +          break;
    +        case EXPIRED:
    +          expiredEvents++;
    +          emitExpired(td.getKey());
    +          entries.remove();
    +          break;
    +        default:
    +          /*
    +           * Decision for this is still UNKNOWN. Tuple is still waiting for bucket to be loaded. Break.
    +           */
    +          break;
    +      }
    +    }
    +  }
    +
    +  @Override
    +  public void teardown()
    +  {
    +    managedState.teardown();
    +  }
    +
    +  @Override
    +  public void beforeCheckpoint(long windowId)
    +  {
    +    managedState.beforeCheckpoint(windowId);
    +  }
    +
    +  @Override
    +  public void checkpointed(long windowId)
    +  {
    +    managedState.checkpointed(windowId);
    +  }
    +
    +  @Override
    +  public void committed(long windowId)
    +  {
    +    managedState.committed(windowId);
    +  }
    +
    +  protected void emitUnique(T event)
    +  {
    +    unique.emit(event);
    +  }
    +
    +  protected void emitDuplicate(T event)
    +  {
    +    duplicate.emit(event);
    +  }
    +
    +  protected void emitExpired(T event)
    +  {
    +    expired.emit(event);
    +  }
    +
    +  /**
    +   * Checks whether output of deduper should preserve the input order
    +   */
    +  public boolean isOrderedOutput()
    +  {
    +    return preserveTupleOrder;
    +  }
    +
    +  /**
    +   * If set to true, the deduper will emit tuples in the order in which they were received. Tuples which arrived later
    +   * will wait for previous tuples to get processed and emitted. If not set, the order of tuples may change as tuples
    +   * may be emitted out of order as and when they get processed.
    +   *
    +   * @param orderedOutput
    +   */
    +  public void setPreserveTupleOrder(boolean preserveTupleOrder)
    +  {
    +    this.preserveTupleOrder = preserveTupleOrder;
    +  }
    +
    +  public ManagedTimeUnifiedStateImpl getManagedState()
    --- End diff --
    
    removed


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