com.hazelcast.mapreduce.impl.task.MappingPhase Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.mapreduce.impl.task;
import com.hazelcast.mapreduce.Context;
import com.hazelcast.mapreduce.KeyPredicate;
import com.hazelcast.mapreduce.KeyValueSource;
import com.hazelcast.mapreduce.Mapper;
import java.util.Collection;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* This is the base of all mapping phase implementations. It's responsibility is to test keys
* prior to mapping the special value. This is used for preselected key-sets and given
* {@link com.hazelcast.mapreduce.KeyPredicate} implementations.
*
* @param type of the input key
* @param type of the input value
* @param type of the emitted key
* @param type of the emitted value
*/
public abstract class MappingPhase {
private final AtomicBoolean cancelled = new AtomicBoolean();
private final Collection keys;
private final KeyPredicate predicate;
public MappingPhase(Collection keys, KeyPredicate predicate) {
this.keys = keys;
this.predicate = predicate;
}
public void cancel() {
cancelled.set(true);
}
protected boolean isCancelled() {
return cancelled.get();
}
protected boolean matches(KeyIn key) {
if ((keys == null || keys.isEmpty()) && predicate == null) {
return true;
}
if (keys != null && !keys.isEmpty()) {
for (KeyIn matcher : keys) {
if (key.equals(matcher)) {
return true;
}
}
}
return predicate != null && predicate.evaluate(key);
}
protected abstract void executeMappingPhase(KeyValueSource keyValueSource,
Mapper mapper,
Context context);
}