| /** |
| * 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.task.impl; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| 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.hadoop.util.Progressable; |
| import org.apache.tez.engine.common.sort.impl.TezRawKeyValueIterator; |
| |
| |
| /** |
| * Iterates values while keys match in sorted input. |
| * |
| * Usage: Call moveToNext to move to the next k, v pair. This returns true if another exists, |
| * followed by getKey() and getValues() to get the current key and list of values. |
| * |
| */ |
| public class ValuesIterator<KEY,VALUE> implements Iterator<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; |
| protected Progressable reporter; |
| private Deserializer<KEY> keyDeserializer; |
| private Deserializer<VALUE> valDeserializer; |
| private DataInputBuffer keyIn = new DataInputBuffer(); |
| private DataInputBuffer valueIn = new DataInputBuffer(); |
| |
| public ValuesIterator (TezRawKeyValueIterator in, |
| RawComparator<KEY> comparator, |
| Class<KEY> keyClass, |
| Class<VALUE> valClass, Configuration conf, |
| Progressable reporter) |
| throws IOException { |
| this.in = in; |
| this.comparator = comparator; |
| this.reporter = reporter; |
| SerializationFactory serializationFactory = new SerializationFactory(conf); |
| this.keyDeserializer = serializationFactory.getDeserializer(keyClass); |
| this.keyDeserializer.open(keyIn); |
| this.valDeserializer = serializationFactory.getDeserializer(valClass); |
| this.valDeserializer.open(this.valueIn); |
| readNextKey(); |
| key = nextKey; |
| nextKey = null; // force new instance creation |
| hasNext = more; |
| } |
| |
| TezRawKeyValueIterator getRawIterator() { return in; } |
| |
| /// Iterator methods |
| |
| public boolean hasNext() { return hasNext; } |
| |
| private int ctr = 0; |
| public VALUE next() { |
| if (!hasNext) { |
| throw new NoSuchElementException("iterate past last value"); |
| } |
| try { |
| readNextValue(); |
| readNextKey(); |
| } catch (IOException ie) { |
| throw new RuntimeException("problem advancing post rec#"+ctr, ie); |
| } |
| reporter.progress(); |
| return value; |
| } |
| |
| public void remove() { throw new RuntimeException("not implemented"); } |
| |
| /// Auxiliary methods |
| |
| /** Start processing next unique key. */ |
| public void nextKey() throws IOException { |
| // read until we find a new key |
| while (hasNext) { |
| readNextKey(); |
| } |
| ++ctr; |
| |
| // move the next key to the current one |
| KEY tmpKey = key; |
| key = nextKey; |
| nextKey = tmpKey; |
| hasNext = more; |
| } |
| |
| /** True iff more keys remain. */ |
| public boolean more() { |
| return more; |
| } |
| |
| /** The current key. */ |
| public KEY getKey() { |
| return key; |
| } |
| |
| /** |
| * read the next key |
| */ |
| private void readNextKey() throws IOException { |
| more = in.next(); |
| if (more) { |
| DataInputBuffer nextKeyBytes = in.getKey(); |
| keyIn.reset(nextKeyBytes.getData(), nextKeyBytes.getPosition(), nextKeyBytes.getLength()); |
| nextKey = keyDeserializer.deserialize(nextKey); |
| hasNext = key != null && (comparator.compare(key, nextKey) == 0); |
| } else { |
| hasNext = false; |
| } |
| } |
| |
| /** |
| * Read the next value |
| * @throws IOException |
| */ |
| private void readNextValue() throws IOException { |
| DataInputBuffer nextValueBytes = in.getValue(); |
| valueIn.reset(nextValueBytes.getData(), nextValueBytes.getPosition(), nextValueBytes.getLength()); |
| value = valDeserializer.deserialize(value); |
| } |
| } |