Package org.apache.flink.runtime.iterative.event

Source Code of org.apache.flink.runtime.iterative.event.IterationEventWithAggregators

/*
* 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.flink.runtime.iterative.event;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Map;

import org.apache.flink.api.common.aggregators.Aggregator;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.core.memory.InputViewDataInputStreamWrapper;
import org.apache.flink.core.memory.OutputViewDataOutputStreamWrapper;
import org.apache.flink.runtime.event.task.AbstractTaskEvent;
import org.apache.flink.types.Value;
import org.apache.flink.util.InstantiationUtil;

public abstract class IterationEventWithAggregators extends AbstractTaskEvent {
 
  protected static final String[] NO_STRINGS = new String[0];
  protected static final Value[] NO_VALUES = new Value[0];
 
  private String[] aggNames;
 
  private String[] classNames;
  private byte[][] serializedData;

  private Value[] aggregates;

  protected IterationEventWithAggregators() {
    this.aggNames = NO_STRINGS;
    this.aggregates = NO_VALUES;
  }

  protected IterationEventWithAggregators(String aggregatorName, Value aggregate) {
    if (aggregatorName == null || aggregate == null) {
      throw new NullPointerException();
    }
   
    this.aggNames = new String[] { aggregatorName };
    this.aggregates = new Value[] { aggregate };
  }
 
  protected IterationEventWithAggregators(Map<String, Aggregator<?>> aggregators) {
    int num = aggregators.size();
    if (num == 0) {
      this.aggNames = NO_STRINGS;
      this.aggregates = NO_VALUES;
    } else {
      this.aggNames = new String[num];
      this.aggregates = new Value[num];
     
      int i = 0;
      for (Map.Entry<String, Aggregator<?>> entry : aggregators.entrySet()) {
        this.aggNames[i] = entry.getKey();
        this.aggregates[i] = entry.getValue().getAggregate();
        i++;
      }
    }
  }
 
  public String[] getAggregatorNames() {
    return this.aggNames;
  }

  public Value[] getAggregates(ClassLoader classResolver) {
    if (aggregates == null) {
      // we have read the binary data, but not yet turned into the objects
      final int num = aggNames.length;
      aggregates = new Value[num];
      for (int i = 0; i < num; i++) {
        Value v;
        try {
          Class<? extends Value> valClass = Class.forName(classNames[i], true, classResolver).asSubclass(Value.class);
          v = InstantiationUtil.instantiate(valClass, Value.class);
        }
        catch (ClassNotFoundException e) {
          throw new RuntimeException("Could not load user-defined class '" + classNames[i] + "'.", e);
        }
        catch (ClassCastException e) {
          throw new RuntimeException("User-defined aggregator class is not a value sublass.");
        }
       
        DataInputStream in = new DataInputStream(new ByteArrayInputStream(serializedData[i]));
        try {
          v.read(new InputViewDataInputStreamWrapper(in));
          in.close();
        } catch (IOException e) {
          throw new RuntimeException("Error while deserializing the user-defined aggregate class.", e);
        }
       
        aggregates[i] = v;
      }
    }
   
    return this.aggregates;
  }

  @Override
  public void write(DataOutputView out) throws IOException {
    int num = this.aggNames.length;
    out.writeInt(num);
   
    ByteArrayOutputStream boas = new ByteArrayOutputStream();
    DataOutputStream bufferStream = new DataOutputStream(boas);
   
    for (int i = 0; i < num; i++) {
      // aggregator name and type
      out.writeUTF(this.aggNames[i]);
      out.writeUTF(this.aggregates[i].getClass().getName());
     
      // aggregator value indirect as a byte array
      this.aggregates[i].write(new OutputViewDataOutputStreamWrapper(bufferStream));
      bufferStream.flush();
      byte[] bytes = boas.toByteArray();
      out.writeInt(bytes.length);
      out.write(bytes);
      boas.reset();
    }
    bufferStream.close();
    boas.close();
  }

  @Override
  public void read(DataInputView in) throws IOException {
    int num = in.readInt();
    if (num == 0) {
      this.aggNames = NO_STRINGS;
      this.aggregates = NO_VALUES;
    } else {
      if (this.aggNames == null || num > this.aggNames.length) {
        this.aggNames = new String[num];
      }
      if (this.classNames == null || num > this.classNames.length) {
        this.classNames = new String[num];
      }
      if (this.serializedData == null || num > this.serializedData.length) {
        this.serializedData = new byte[num][];
      }

      for (int i = 0; i < num; i++) {
        this.aggNames[i] = in.readUTF();
        this.classNames[i] = in.readUTF();
       
        int len = in.readInt();
        byte[] data = new byte[len];
        this.serializedData[i] = data;
        in.readFully(data);
       
      }
     
      this.aggregates = null;
    }
  }
}
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