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From chinmaykolhatkar <...@git.apache.org>
Subject [GitHub] apex-malhar pull request #319: APEXMALHAR-2085: REVIEW ONLY: Operator suppor...
Date Mon, 27 Jun 2016 23:52:57 GMT
Github user chinmaykolhatkar commented on a diff in the pull request:

    https://github.com/apache/apex-malhar/pull/319#discussion_r68677141
  
    --- Diff: library/src/main/java/org/apache/apex/malhar/lib/window/impl/AbstractWindowedOperator.java
---
    @@ -0,0 +1,490 @@
    +/**
    + * 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.window.impl;
    +
    +import java.util.ArrayList;
    +import java.util.Iterator;
    +import java.util.List;
    +import java.util.Map;
    +
    +import javax.validation.ValidationException;
    +
    +import org.joda.time.Duration;
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import org.apache.apex.malhar.lib.window.Accumulation;
    +import org.apache.apex.malhar.lib.window.ControlTuple;
    +import org.apache.apex.malhar.lib.window.TriggerOption;
    +import org.apache.apex.malhar.lib.window.Tuple;
    +import org.apache.apex.malhar.lib.window.Window;
    +import org.apache.apex.malhar.lib.window.WindowOption;
    +import org.apache.apex.malhar.lib.window.WindowState;
    +import org.apache.apex.malhar.lib.window.WindowedOperator;
    +import org.apache.apex.malhar.lib.window.WindowedStorage;
    +import org.apache.hadoop.classification.InterfaceStability;
    +
    +import com.google.common.base.Function;
    +
    +import com.datatorrent.api.Context;
    +import com.datatorrent.api.DefaultInputPort;
    +import com.datatorrent.api.DefaultOutputPort;
    +import com.datatorrent.api.annotation.InputPortFieldAnnotation;
    +import com.datatorrent.common.util.BaseOperator;
    +
    +/**
    + * This is the abstract windowed operator class that implements most of the windowing,
triggering, and accumulating
    + * concepts. The subclass of this abstract class is supposed to provide the implementation
of how the accumulated
    + * values are stored in the storage.
    + *
    + * @param <InputT> The type of the input tuple
    + * @param <OutputT> The type of the output tuple
    + * @param <DataStorageT> The type of the data storage
    + * @param <AccumulationT> The type of the accumulation
    + */
    +@InterfaceStability.Evolving
    +public abstract class AbstractWindowedOperator<InputT, OutputT, DataStorageT extends
WindowedStorage, AccumulationT extends Accumulation>
    +    extends BaseOperator implements WindowedOperator<InputT>
    +{
    +
    +  protected WindowOption windowOption;
    +  protected TriggerOption triggerOption;
    +  protected long allowedLatenessMillis = -1;
    +  protected WindowedStorage<WindowState> windowStateMap;
    +
    +  private Function<InputT, Long> timestampExtractor;
    +
    +  private long currentWatermark;
    +  private boolean triggerAtWatermark;
    +  private long earlyTriggerCount;
    +  private long earlyTriggerMillis;
    +  private long lateTriggerCount;
    +  private long lateTriggerMillis;
    +  private long currentDerivedTimestamp = -1;
    +  private long windowWidthMillis;
    +  protected DataStorageT dataStorage;
    +  protected DataStorageT retractionStorage;
    +  protected AccumulationT accumulation;
    +
    +  private static final transient Logger LOG = LoggerFactory.getLogger(AbstractWindowedOperator.class);
    +
    +  public final transient DefaultInputPort<Tuple<InputT>> input = new DefaultInputPort<Tuple<InputT>>()
    +  {
    +    @Override
    +    public void process(Tuple<InputT> tuple)
    +    {
    +      processTuple(tuple);
    +    }
    +  };
    +
    +  // TODO: This port should be removed when Apex Core has native support for custom control
tuples
    +  @InputPortFieldAnnotation(optional = true)
    +  public final transient DefaultInputPort<ControlTuple> controlInput = new DefaultInputPort<ControlTuple>()
    +  {
    +    @Override
    +    public void process(ControlTuple tuple)
    +    {
    +      if (tuple instanceof ControlTuple.Watermark) {
    +        processWatermark((ControlTuple.Watermark)tuple);
    +      }
    +    }
    +  };
    +
    +
    +  // TODO: multiple input ports for join operations
    +
    +  public final transient DefaultOutputPort<Tuple<OutputT>> output = new DefaultOutputPort<>();
    +
    +  // TODO: This port should be removed when Apex Core has native support for custom control
tuples
    +  public final transient DefaultOutputPort<ControlTuple> controlOutput = new DefaultOutputPort<>();
    +
    +  /**
    +   * Process the incoming data tuple
    +   *
    +   * @param tuple
    +   */
    +  public void processTuple(Tuple<InputT> tuple)
    +  {
    +    long timestamp = extractTimestamp(tuple);
    +    if (isTooLate(timestamp)) {
    +      dropTuple(tuple);
    +    } else {
    +      Tuple.WindowedTuple<InputT> windowedTuple = getWindowedValue(tuple);
    +      // do the accumulation
    +      accumulateTuple(windowedTuple);
    +
    +      for (Window window : windowedTuple.getWindows()) {
    +        WindowState windowState = windowStateMap.get(window);
    +        windowState.tupleCount++;
    +        // process any count based triggers
    +        if (windowState.watermarkArrivalTime == -1) {
    +          // watermark has not arrived yet, check for early count based trigger
    +          if (earlyTriggerCount > 0 && (windowState.tupleCount % earlyTriggerCount)
== 0) {
    +            fireTrigger(window, windowState);
    +          }
    +        } else {
    +          // watermark has arrived, check for late count based trigger
    +          if (lateTriggerCount > 0 && (windowState.tupleCount % lateTriggerCount)
== 0) {
    +            fireTrigger(window, windowState);
    +          }
    +        }
    +      }
    +    }
    +  }
    +
    +  @Override
    +  public void setWindowOption(WindowOption windowOption)
    +  {
    +    this.windowOption = windowOption;
    +    if (this.windowOption instanceof WindowOption.GlobalWindow) {
    +      windowStateMap.put(Window.GLOBAL_WINDOW, new WindowState());
    +    }
    +  }
    +
    +  @Override
    +  public void setTriggerOption(TriggerOption triggerOption)
    +  {
    +    this.triggerOption = triggerOption;
    +    for (TriggerOption.Trigger trigger : triggerOption.getTriggerList()) {
    +      switch (trigger.getWatermarkOpt()) {
    +        case ON_TIME:
    +          triggerAtWatermark = true;
    +          break;
    +        case EARLY:
    +          if (trigger instanceof TriggerOption.TimeTrigger) {
    +            earlyTriggerMillis = ((TriggerOption.TimeTrigger)trigger).getDuration().getMillis();
    +          } else if (trigger instanceof TriggerOption.CountTrigger) {
    +            earlyTriggerCount = ((TriggerOption.CountTrigger)trigger).getCount();
    +          }
    +          break;
    +        case LATE:
    +          if (trigger instanceof TriggerOption.TimeTrigger) {
    +            lateTriggerMillis = ((TriggerOption.TimeTrigger)trigger).getDuration().getMillis();
    +          } else if (trigger instanceof TriggerOption.CountTrigger) {
    +            lateTriggerCount = ((TriggerOption.CountTrigger)trigger).getCount();
    +          }
    +          break;
    +        default:
    +          throw new RuntimeException("Unexpected watermark option: " + trigger.getWatermarkOpt());
    +      }
    +    }
    +  }
    +
    +  @Override
    +  public void setAllowedLateness(Duration allowedLateness)
    +  {
    +    this.allowedLatenessMillis = allowedLateness.getMillis();
    +  }
    +
    +  /**
    +   * This method sets the storage for the data for each window
    +   *
    +   * @param storageAgent
    +   */
    +  public void setDataStorage(DataStorageT storageAgent)
    +  {
    +    this.dataStorage = storageAgent;
    +  }
    +
    +  /**
    +   * This method sets the storage for the retraction data for each window. Only used
when the accumulation mode is ACCUMULATING_AND_RETRACTING
    +   *
    +   * @param storageAgent
    +   */
    +  public void setRetractionStorage(DataStorageT storageAgent)
    +  {
    +    this.retractionStorage = storageAgent;
    +  }
    +
    +  /**
    +   * Sets the accumulation, which basically tells the WindowedOperator what to do if
a new tuple comes in and what
    +   * to put in the pane when a trigger is fired
    +   *
    +   * @param accumulation
    +   */
    +  public void setAccumulation(AccumulationT accumulation)
    +  {
    +    this.accumulation = accumulation;
    +  }
    +
    +  @Override
    +  public void setWindowStateStorage(WindowedStorage<WindowState> storageAgent)
    +  {
    +    this.windowStateMap = storageAgent;
    +  }
    +
    +  @Override
    +  public void setTimestampExtractor(Function<InputT, Long> timestampExtractor)
    +  {
    +    this.timestampExtractor = timestampExtractor;
    +  }
    +
    +  public void validate() throws ValidationException
    +  {
    +    if (accumulation == null) {
    +      throw new ValidationException("Accumulation must be set");
    +    }
    +    if (dataStorage == null) {
    +      throw new ValidationException("Data storage must be set");
    +    }
    +    if (windowStateMap == null) {
    +      throw new ValidationException("Window state storage must be set");
    +    }
    +    if (triggerOption != null) {
    +      if (triggerOption.isFiringOnlyUpdatedPanes()) {
    +        if (retractionStorage == null) {
    +          throw new ValidationException("A retraction storage is required for firingOnlyUpdatedPanes
option");
    +        }
    +        if (triggerOption.getAccumulationMode() == TriggerOption.AccumulationMode.DISCARDING)
{
    +          throw new ValidationException("DISCARDING accumulation mode is not valid for
firingOnlyUpdatedPanes option");
    +        }
    +      }
    +      if (triggerOption.getAccumulationMode() == TriggerOption.AccumulationMode.ACCUMULATING_AND_RETRACTING
&&
    +          retractionStorage == null) {
    +        throw new ValidationException("A retraction storage is required for ACCUMULATING_AND_RETRACTING
accumulation mode");
    +      }
    +    }
    +  }
    +
    +  @Override
    +  public Tuple.WindowedTuple<InputT> getWindowedValue(Tuple<InputT> input)
    +  {
    +    Tuple.WindowedTuple<InputT> windowedTuple = new Tuple.WindowedTuple<>();
    +    windowedTuple.setValue(input.getValue());
    +    windowedTuple.setTimestamp(extractTimestamp(input));
    +    assignWindows(windowedTuple.getWindows(), input);
    +    return windowedTuple;
    +  }
    +
    +  private long extractTimestamp(Tuple<InputT> tuple)
    +  {
    +    if (timestampExtractor == null) {
    +      if (tuple instanceof Tuple.TimestampedTuple) {
    +        return ((Tuple.TimestampedTuple)tuple).getTimestamp();
    +      } else {
    +        return 0;
    +      }
    +    } else {
    +      return timestampExtractor.apply(tuple.getValue());
    +    }
    +  }
    +
    +  private void assignWindows(List<Window> windows, Tuple<InputT> inputTuple)
    +  {
    +    if (windowOption instanceof WindowOption.GlobalWindow) {
    +      windows.add(Window.GLOBAL_WINDOW);
    +    } else {
    +      long timestamp = extractTimestamp(inputTuple);
    +      if (windowOption instanceof WindowOption.TimeWindows) {
    +
    +        for (Window.TimeWindow window : getTimeWindowsForTimestamp(timestamp)) {
    +          if (!windowStateMap.containsWindow(window)) {
    +            windowStateMap.put(window, new WindowState());
    +          }
    +          windows.add(window);
    +        }
    +      } else if (windowOption instanceof WindowOption.SessionWindows) {
    +        assignSessionWindows(windows, timestamp, inputTuple);
    +      }
    +    }
    +  }
    +
    +  protected void assignSessionWindows(List<Window> windows, long timestamp, Tuple<InputT>
inputTuple)
    +  {
    +    throw new UnsupportedOperationException();
    +  }
    +
    +  /**
    +   * Returns the list of windows TimeWindows for the given timestamp.
    +   * If we are doing sliding windows, this will return multiple windows. Otherwise, only
one window will be returned.
    +   * Note that this method does not apply to SessionWindows.
    +   *
    +   * @param timestamp
    +   * @return
    +   */
    +  private List<Window.TimeWindow> getTimeWindowsForTimestamp(long timestamp)
    +  {
    +    List<Window.TimeWindow> windows = new ArrayList<>();
    +    if (windowOption instanceof WindowOption.TimeWindows) {
    +      long durationMillis = ((WindowOption.TimeWindows)windowOption).getDuration().getMillis();
    +      long beginTimestamp = timestamp - timestamp % durationMillis;
    +      windows.add(new Window.TimeWindow(beginTimestamp, durationMillis));
    +      if (windowOption instanceof WindowOption.SlidingTimeWindows) {
    +        long slideBy = ((WindowOption.SlidingTimeWindows)windowOption).getSlideByDuration().getMillis();
    +        // add the sliding windows front and back
    +        // Note: this messes up the order of the window and we might want to revisit
this if the order of the windows
    +        // matter
    +        for (long slideBeginTimestamp = beginTimestamp - slideBy;
    +            slideBeginTimestamp <= timestamp && timestamp < slideBeginTimestamp
+ durationMillis;
    +            slideBeginTimestamp -= slideBy) {
    +          windows.add(new Window.TimeWindow(slideBeginTimestamp, durationMillis));
    +        }
    +        for (long slideBeginTimestamp = beginTimestamp + slideBy;
    +            slideBeginTimestamp <= timestamp && timestamp < slideBeginTimestamp
+ durationMillis;
    +            slideBeginTimestamp += slideBy) {
    +          windows.add(new Window.TimeWindow(slideBeginTimestamp, durationMillis));
    +        }
    +      }
    +    } else {
    +      throw new IllegalStateException("Unexpected WindowOption");
    +    }
    +    return windows;
    +  }
    +
    +  @Override
    +  public boolean isTooLate(long timestamp)
    +  {
    +    return allowedLatenessMillis < 0 ? false : (timestamp < currentWatermark -
allowedLatenessMillis);
    +  }
    +
    +  @Override
    +  public void dropTuple(Tuple<InputT> input)
    +  {
    +    // do nothing
    +    LOG.debug("Dropping late tuple {}", input);
    +  }
    +
    +
    +  @Override
    +  public void processWatermark(ControlTuple.Watermark watermark)
    +  {
    +    currentWatermark = watermark.getTimestamp();
    +    long horizon = currentWatermark - allowedLatenessMillis;
    +    if (allowedLatenessMillis >= 0) {
    +      // purge window that are too late to accept any more input
    +      dataStorage.removeUpTo(horizon);
    +    }
    +
    +    for (Iterator<Map.Entry<Window, WindowState>> it = windowStateMap.iterator();
it.hasNext(); ) {
    +      Map.Entry<Window, WindowState> entry = it.next();
    +      Window window = entry.getKey();
    +      WindowState windowState = entry.getValue();
    +      if (allowedLatenessMillis >= 0 && window.getBeginTimestamp() + window.getDurationMillis()
< horizon) {
    +        // discard this window because it's too late now
    +        it.remove();
    +      } else if (window.getBeginTimestamp() + window.getDurationMillis() < currentWatermark)
{
    +        // watermark has not arrived for this window before, marking this window late
    +        if (windowState.watermarkArrivalTime == -1) {
    +          windowState.watermarkArrivalTime = currentDerivedTimestamp;
    +          if (triggerAtWatermark) {
    --- End diff --
    
    Can we make this property default true in that case?
    If we're going by mean specifications, then even if TriggerOption list not having ON_TIME
is set, should make sure by default that trigger happens at watermark.


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