com.hazelcast.nio.tcp.nonblocking.iobalancer.MonkeyMigrationStrategy Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2016, 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.nio.tcp.nonblocking.iobalancer;
import com.hazelcast.nio.tcp.nonblocking.MigratableHandler;
import java.util.Iterator;
import java.util.Random;
import java.util.Set;
/**
* IOBalancer Migration Strategy intended to be used by stress tests only. It always tries to
* select a random {@link MigratableHandler handler} to be migrated.
*
* It stresses the handler migration mechanism increasing a chance to reveal possible race-conditions.
*/
class MonkeyMigrationStrategy implements MigrationStrategy {
private final Random random = new Random();
@Override
public boolean imbalanceDetected(LoadImbalance imbalance) {
Set candidates = imbalance.getHandlersOwnerBy(imbalance.sourceSelector);
//only attempts to migrate if at least 1 handler exists
return (candidates.size() > 0);
}
@Override
public MigratableHandler findHandlerToMigrate(LoadImbalance imbalance) {
Set candidates = imbalance.getHandlersOwnerBy(imbalance.sourceSelector);
int handlerCount = candidates.size();
int selected = random.nextInt(handlerCount);
Iterator iterator = candidates.iterator();
for (int i = 0; i < selected; i++) {
iterator.next();
}
return iterator.next();
}
}