eu.stratosphere.nephele.instance.cluster.PendingRequestsMap Maven / Gradle / Ivy
/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.nephele.instance.cluster;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import eu.stratosphere.nephele.instance.InstanceType;
/**
* This class represents a pending request, i.e. a request for a particular type and number of {@link AbstractInstance}
* objects which could not be fulfilled yet.
*
* This class is not thread-safe.
*
*/
public final class PendingRequestsMap {
/**
* The map storing the pending instance requests for the job this pending request object belongs to.
*/
private final Map pendingRequests = new HashMap();
/**
* Checks if the job this object belongs to has pending instance requests.
*
* @return true if the job this object belongs to has pending instance requests, false
* otherwise
*/
boolean hasPendingRequests() {
return !(this.pendingRequests.isEmpty());
}
/**
* Adds the a pending request for the given number of instances of the given type to this map.
*
* @param instanceType
* the requested instance type
* @param numberOfInstances
* the requested number of instances of this type
*/
void addRequest(final InstanceType instanceType, final int numberOfInstances) {
Integer numberOfRemainingInstances = this.pendingRequests.get(instanceType);
if (numberOfRemainingInstances == null) {
numberOfRemainingInstances = Integer.valueOf(numberOfInstances);
} else {
numberOfRemainingInstances = Integer.valueOf(numberOfRemainingInstances.intValue() + numberOfInstances);
}
this.pendingRequests.put(instanceType, numberOfRemainingInstances);
}
/**
* Returns an iterator for the pending requests encapsulated in this map.
*
* @return an iterator for the pending requests encapsulated in this map
*/
Iterator> iterator() {
return this.pendingRequests.entrySet().iterator();
}
/**
* Decreases the number of remaining instances to request of the given type.
*
* @param instanceType
* the instance type for which the number of remaining instances shall be decreased
*/
void decreaseNumberOfPendingInstances(final InstanceType instanceType) {
Integer numberOfRemainingInstances = this.pendingRequests.get(instanceType);
if (numberOfRemainingInstances == null) {
return;
}
numberOfRemainingInstances = Integer.valueOf(numberOfRemainingInstances.intValue() - 1);
if (numberOfRemainingInstances.intValue() == 0) {
this.pendingRequests.remove(instanceType);
} else {
this.pendingRequests.put(instanceType, numberOfRemainingInstances);
}
}
}