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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.hadoop.mapred;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.concurrent.ConcurrentHashMap;
// HashSet and HashMap do not guarantee that the oder of iteration is
// determinstic. We need the latter for the deterministic replay of
// simulations. These iterations are heavily used in the JobTracker, e.g. when
// looking for non-local map tasks. Not all HashSet and HashMap instances
// are iterated over, but to be safe and simple we replace all with
// LinkedHashSet and LinkedHashMap whose iteration order is deterministic.
public privileged aspect DeterministicCollectionAspects {
// Fortunately the Java runtime type of generic classes do not contain
// the generic parameter. We can catch all with a single base pattern using
// the erasure of the generic type.
HashSet around() : call(HashSet.new()) {
return new LinkedHashSet();
}
HashMap around() : call(HashMap.new()) {
return new LinkedHashMap();
}
ConcurrentHashMap around() : call(ConcurrentHashMap.new()) {
return new FakeConcurrentHashMap();
}
}