001/*
002 * Copyright 2006-2013 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.springframework.batch.core.job.flow.support.state;
017
018import java.util.Collection;
019import java.util.Collections;
020
021import org.springframework.batch.core.job.flow.FlowExecution;
022import org.springframework.batch.core.job.flow.FlowExecutionStatus;
023
024/**
025 * Implementation of the {@link FlowExecutionAggregator} interface that aggregates
026 * {@link FlowExecutionStatus}', using the status with the high precedence as the
027 * aggregate status.  See {@link FlowExecutionStatus} for details on status
028 * precedence.
029 *
030 * @author Dave Syer
031 * @since 2.0
032 */
033public class MaxValueFlowExecutionAggregator implements FlowExecutionAggregator {
034
035        /**
036         * Aggregate all of the {@link FlowExecutionStatus}es of the
037         * {@link FlowExecution}s into one status. The aggregate status will be the
038         * status with the highest precedence.
039         *
040         * @see FlowExecutionAggregator#aggregate(Collection)
041         */
042        @Override
043        public FlowExecutionStatus aggregate(Collection<FlowExecution> executions) {
044                if (executions == null || executions.size() == 0) {
045                        return FlowExecutionStatus.UNKNOWN;
046                }
047                return Collections.max(executions).getStatus();
048        }
049
050}