/***********************************************************************************************************************
* 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.pact.runtime.iterative.convergence;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import eu.stratosphere.api.common.aggregators.ConvergenceCriterion;
import eu.stratosphere.types.LongValue;
/**
* A workset iteration is by definition converged if no records have been updated in the solutionset
*/
public class WorksetEmptyConvergenceCriterion implements ConvergenceCriterion<LongValue> {
private static final Log log = LogFactory.getLog(WorksetEmptyConvergenceCriterion.class);
public static final String AGGREGATOR_NAME = "pact.runtime.workset-empty-aggregator";
@Override
public boolean isConverged(int iteration, LongValue value) {
long updatedElements = value.getValue();
if (log.isInfoEnabled()) {
log.info("[" + updatedElements + "] elements updated in the solutionset in iteration [" + iteration + "]");
}
return updatedElements == 0;
}
}