| /** |
| * 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.hadoop.io.serializer; |
| |
| import java.io.IOException; |
| import java.util.Comparator; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.io.InputBuffer; |
| import org.apache.hadoop.io.RawComparator; |
| |
| /** |
| * <p> |
| * A {@link RawComparator} that uses a {@link Deserializer} to deserialize |
| * the objects to be compared so that the standard {@link Comparator} can |
| * be used to compare them. |
| * </p> |
| * <p> |
| * One may optimize compare-intensive operations by using a custom |
| * implementation of {@link RawComparator} that operates directly |
| * on byte representations. |
| * </p> |
| * @param <T> |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"}) |
| @InterfaceStability.Evolving |
| public abstract class DeserializerComparator<T> implements RawComparator<T> { |
| |
| private InputBuffer buffer = new InputBuffer(); |
| private Deserializer<T> deserializer; |
| |
| private T key1; |
| private T key2; |
| |
| protected DeserializerComparator(Deserializer<T> deserializer) |
| throws IOException { |
| |
| this.deserializer = deserializer; |
| this.deserializer.open(buffer); |
| } |
| |
| @Override |
| public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) { |
| try { |
| |
| buffer.reset(b1, s1, l1); |
| key1 = deserializer.deserialize(key1); |
| |
| buffer.reset(b2, s2, l2); |
| key2 = deserializer.deserialize(key2); |
| |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| return compare(key1, key2); |
| } |
| |
| } |