org.apache.tez.engine.common.combine.CombineInput.java Source code

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Here is the source code for org.apache.tez.engine.common.combine.CombineInput.java

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/**
 * 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.tez.engine.common.combine;

import java.io.IOException;
import java.util.Iterator;
import java.util.NoSuchElementException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.io.serializer.Deserializer;
import org.apache.hadoop.util.Progressable;
import org.apache.tez.common.counters.TezCounter;
import org.apache.tez.engine.api.Input;
import org.apache.tez.engine.api.Master;
import org.apache.tez.engine.common.sort.impl.TezRawKeyValueIterator;

@SuppressWarnings({ "unchecked", "rawtypes" })
public class CombineInput implements Input {

    private final TezRawKeyValueIterator input;
    private TezCounter inputValueCounter;
    private TezCounter inputKeyCounter;
    private RawComparator<Object> comparator;
    private Object key; // current key
    private Object value; // current value
    private boolean firstValue = false; // first value in key
    private boolean nextKeyIsSame = false; // more w/ this key
    private boolean hasMore; // more in file
    protected Progressable reporter;
    private Deserializer keyDeserializer;
    private Deserializer valueDeserializer;
    private DataInputBuffer buffer = new DataInputBuffer();
    private BytesWritable currentRawKey = new BytesWritable();
    private ValueIterable iterable = new ValueIterable();

    public CombineInput(TezRawKeyValueIterator kvIter) {
        this.input = kvIter;
    }

    public void initialize(Configuration conf, Master master) throws IOException, InterruptedException {
    }

    public boolean hasNext() throws IOException, InterruptedException {
        while (hasMore && nextKeyIsSame) {
            nextKeyValue();
        }
        if (hasMore) {
            if (inputKeyCounter != null) {
                inputKeyCounter.increment(1);
            }
            return nextKeyValue();
        } else {
            return false;
        }
    }

    private boolean nextKeyValue() throws IOException, InterruptedException {
        if (!hasMore) {
            key = null;
            value = null;
            return false;
        }
        firstValue = !nextKeyIsSame;
        DataInputBuffer nextKey = input.getKey();
        currentRawKey.set(nextKey.getData(), nextKey.getPosition(), nextKey.getLength() - nextKey.getPosition());
        buffer.reset(currentRawKey.getBytes(), 0, currentRawKey.getLength());
        key = keyDeserializer.deserialize(key);
        DataInputBuffer nextVal = input.getValue();
        buffer.reset(nextVal.getData(), nextVal.getPosition(), nextVal.getLength());
        value = valueDeserializer.deserialize(value);

        hasMore = input.next();
        if (hasMore) {
            nextKey = input.getKey();
            nextKeyIsSame = comparator.compare(currentRawKey.getBytes(), 0, currentRawKey.getLength(),
                    nextKey.getData(), nextKey.getPosition(), nextKey.getLength() - nextKey.getPosition()) == 0;
        } else {
            nextKeyIsSame = false;
        }
        inputValueCounter.increment(1);
        return true;
    }

    public Object getNextKey() throws IOException, InterruptedException {
        return key;
    }

    public Iterable getNextValues() throws IOException, InterruptedException {
        return iterable;
    }

    public float getProgress() throws IOException, InterruptedException {
        return input.getProgress().getProgress();
    }

    public void close() throws IOException {
        input.close();
    }

    public TezRawKeyValueIterator getIterator() {
        return this.input;
    }

    protected class ValueIterator implements Iterator<Object> {

        public boolean hasNext() {
            return firstValue || nextKeyIsSame;
        }

        public Object next() {

            // if this is the first record, we don't need to advance
            if (firstValue) {
                firstValue = false;
                return value;
            }
            // if this isn't the first record and the next key is different, they
            // can't advance it here.
            if (!nextKeyIsSame) {
                throw new NoSuchElementException("iterate past last value");
            }
            // otherwise, go to the next key/value pair
            try {
                nextKeyValue();
                return value;
            } catch (IOException ie) {
                throw new RuntimeException("next value iterator failed", ie);
            } catch (InterruptedException ie) {
                // this is bad, but we can't modify the exception list of java.util
                throw new RuntimeException("next value iterator interrupted", ie);
            }
        }

        public void remove() {
            throw new UnsupportedOperationException("remove not implemented");
        }
    }

    protected class ValueIterable implements Iterable<Object> {
        private ValueIterator iterator = new ValueIterator();

        public Iterator<Object> iterator() {
            return iterator;
        }
    }

}