| /** |
| * 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.runtime.library.common; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| import org.apache.hadoop.classification.InterfaceAudience.Private; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.io.DataInputBuffer; |
| import org.apache.hadoop.io.RawComparator; |
| import org.apache.hadoop.io.serializer.Deserializer; |
| import org.apache.hadoop.io.serializer.SerializationFactory; |
| import org.apache.tez.common.counters.TezCounter; |
| import org.apache.tez.runtime.library.common.sort.impl.TezRawKeyValueIterator; |
| |
| import org.apache.tez.common.Preconditions; |
| |
| /** |
| * Iterates values while keys match in sorted input. |
| * |
| * This class is not thread safe. Accessing methods from multiple threads will |
| * lead to corrupt data. |
| * |
| */ |
| |
| @Private |
| public class ValuesIterator<KEY,VALUE> { |
| protected TezRawKeyValueIterator in; //input iterator |
| private KEY key; // current key |
| private KEY nextKey; |
| private VALUE value; // current value |
| //private boolean hasNext; // more w/ this key |
| private boolean more; // more in file |
| private RawComparator<KEY> comparator; |
| private Deserializer<KEY> keyDeserializer; |
| private Deserializer<VALUE> valDeserializer; |
| private DataInputBuffer keyIn = new DataInputBuffer(); |
| private DataInputBuffer valueIn = new DataInputBuffer(); |
| private TezCounter inputKeyCounter; |
| private TezCounter inputValueCounter; |
| |
| private int keyCtr = 0; |
| private boolean hasMoreValues; // For the current key. |
| private boolean isFirstRecord = true; |
| |
| private boolean completedProcessing; |
| |
| public ValuesIterator (TezRawKeyValueIterator in, |
| RawComparator<KEY> comparator, |
| Class<KEY> keyClass, |
| Class<VALUE> valClass, Configuration conf, |
| TezCounter inputKeyCounter, |
| TezCounter inputValueCounter) |
| throws IOException { |
| this.in = in; |
| this.comparator = comparator; |
| this.inputKeyCounter = inputKeyCounter; |
| this.inputValueCounter = inputValueCounter; |
| SerializationFactory serializationFactory = new SerializationFactory(conf); |
| this.keyDeserializer = serializationFactory.getDeserializer(keyClass); |
| this.keyDeserializer.open(keyIn); |
| this.valDeserializer = serializationFactory.getDeserializer(valClass); |
| this.valDeserializer.open(this.valueIn); |
| } |
| |
| TezRawKeyValueIterator getRawIterator() { return in; } |
| |
| /** |
| * Move to the next K-Vs pair |
| * @return true if another pair exists, otherwise false. |
| * @throws IOException |
| */ |
| public boolean moveToNext() throws IOException { |
| if (isFirstRecord) { |
| readNextKey(); |
| key = nextKey; |
| nextKey = null; |
| isFirstRecord = false; |
| } else { |
| nextKey(); |
| } |
| if (!more) { |
| hasCompletedProcessing(); |
| completedProcessing = true; |
| } |
| return more; |
| } |
| |
| /** The current key. */ |
| public KEY getKey() { |
| return key; |
| } |
| |
| // TODO NEWTEZ Maybe add another method which returns an iterator instead of iterable |
| |
| public Iterable<VALUE> getValues() { |
| return new Iterable<VALUE>() { |
| |
| @Override |
| public Iterator<VALUE> iterator() { |
| |
| return new Iterator<VALUE>() { |
| |
| private final int keyNumber = keyCtr; |
| |
| @Override |
| public boolean hasNext() { |
| return hasMoreValues; |
| } |
| |
| @Override |
| public VALUE next() { |
| if (!hasMoreValues) { |
| throw new NoSuchElementException("iterate past last value"); |
| } |
| Preconditions |
| .checkState( |
| keyNumber == keyCtr, |
| "Cannot use values iterator on the previous K-V pair after moveToNext has been invoked to move to the next K-V pair"); |
| |
| try { |
| readNextValue(); |
| readNextKey(); |
| } catch (IOException ie) { |
| throw new RuntimeException("problem advancing post rec#"+keyCtr, ie); |
| } |
| inputValueCounter.increment(1); |
| return value; |
| } |
| |
| @Override |
| public void remove() { |
| throw new UnsupportedOperationException("Cannot remove elements"); |
| } |
| }; |
| } |
| }; |
| } |
| |
| |
| |
| /** Start processing next unique key. */ |
| private void nextKey() throws IOException { |
| // read until we find a new key |
| while (hasMoreValues) { |
| readNextKey(); |
| } |
| |
| // move the next key to the current one |
| KEY tmpKey = key; |
| key = nextKey; |
| nextKey = tmpKey; |
| hasMoreValues = more; |
| } |
| |
| /** |
| * read the next key - which may be the same as the current key. |
| */ |
| private void readNextKey() throws IOException { |
| more = in.next(); |
| if (more) { |
| DataInputBuffer nextKeyBytes = in.getKey(); |
| if (!in.isSameKey()) { |
| keyIn.reset(nextKeyBytes.getData(), nextKeyBytes.getPosition(), |
| nextKeyBytes.getLength() - nextKeyBytes.getPosition()); |
| nextKey = keyDeserializer.deserialize(nextKey); |
| // hasMoreValues = is it first key or is key the same? |
| hasMoreValues = (key == null) || (comparator.compare(key, nextKey) == 0); |
| if (key == null || false == hasMoreValues) { |
| // invariant: more=true & there are no more values in an existing key group |
| // so this indicates start of new key group |
| if(inputKeyCounter != null) { |
| inputKeyCounter.increment(1); |
| } |
| ++keyCtr; |
| } |
| } else { |
| hasMoreValues = in.isSameKey(); |
| } |
| } else { |
| hasMoreValues = false; |
| } |
| } |
| |
| /** |
| * Read the next value |
| * @throws IOException |
| */ |
| private void readNextValue() throws IOException { |
| DataInputBuffer nextValueBytes = in.getValue(); |
| valueIn.reset(nextValueBytes.getData(), nextValueBytes.getPosition(), |
| nextValueBytes.getLength() - nextValueBytes.getPosition()); |
| value = valDeserializer.deserialize(value); |
| } |
| |
| /** |
| * Check whether processing has been completed. |
| * |
| * @throws IOException |
| */ |
| protected void hasCompletedProcessing() throws IOException { |
| if (completedProcessing) { |
| throw new IOException("Please check if you are invoking moveToNext() even after it returned" |
| + " false."); |
| } |
| } |
| } |