| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.core.job.flow.support.state; |
| 17 | |
| 18 | import java.util.ArrayList; |
| 19 | import java.util.Collection; |
| 20 | import java.util.concurrent.Callable; |
| 21 | import java.util.concurrent.ExecutionException; |
| 22 | import java.util.concurrent.Future; |
| 23 | import java.util.concurrent.FutureTask; |
| 24 | |
| 25 | import org.springframework.batch.core.job.flow.Flow; |
| 26 | import org.springframework.batch.core.job.flow.FlowExecution; |
| 27 | import org.springframework.batch.core.job.flow.FlowExecutionException; |
| 28 | import org.springframework.batch.core.job.flow.FlowExecutionStatus; |
| 29 | import org.springframework.batch.core.job.flow.FlowExecutor; |
| 30 | import org.springframework.batch.core.job.flow.State; |
| 31 | import org.springframework.core.task.SyncTaskExecutor; |
| 32 | import org.springframework.core.task.TaskExecutor; |
| 33 | import org.springframework.core.task.TaskRejectedException; |
| 34 | |
| 35 | /** |
| 36 | * A {@link State} implementation that splits a {@link Flow} into multiple |
| 37 | * parallel subflows. |
| 38 | * |
| 39 | * @author Dave Syer |
| 40 | * @since 2.0 |
| 41 | */ |
| 42 | public class SplitState extends AbstractState { |
| 43 | |
| 44 | private final Collection<Flow> flows; |
| 45 | |
| 46 | private TaskExecutor taskExecutor = new SyncTaskExecutor(); |
| 47 | |
| 48 | private FlowExecutionAggregator aggregator = new MaxValueFlowExecutionAggregator(); |
| 49 | |
| 50 | /** |
| 51 | * @param name |
| 52 | */ |
| 53 | public SplitState(Collection<Flow> flows, String name) { |
| 54 | super(name); |
| 55 | this.flows = flows; |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * Public setter for the taskExecutor. |
| 60 | * @param taskExecutor the taskExecutor to set |
| 61 | */ |
| 62 | public void setTaskExecutor(TaskExecutor taskExecutor) { |
| 63 | this.taskExecutor = taskExecutor; |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Execute the flows in parallel by passing them to the {@link TaskExecutor} |
| 68 | * and wait for all of them to finish before proceeding. |
| 69 | * |
| 70 | * @see State#handle(FlowExecutor) |
| 71 | */ |
| 72 | @Override |
| 73 | public FlowExecutionStatus handle(final FlowExecutor executor) throws Exception { |
| 74 | |
| 75 | // TODO: collect the last StepExecution from the flows as well, so they |
| 76 | // can be abandoned if necessary |
| 77 | Collection<Future<FlowExecution>> tasks = new ArrayList<Future<FlowExecution>>(); |
| 78 | |
| 79 | for (final Flow flow : flows) { |
| 80 | |
| 81 | final FutureTask<FlowExecution> task = new FutureTask<FlowExecution>(new Callable<FlowExecution>() { |
| 82 | public FlowExecution call() throws Exception { |
| 83 | return flow.start(executor); |
| 84 | } |
| 85 | }); |
| 86 | |
| 87 | tasks.add(task); |
| 88 | |
| 89 | try { |
| 90 | taskExecutor.execute(task); |
| 91 | } |
| 92 | catch (TaskRejectedException e) { |
| 93 | throw new FlowExecutionException("TaskExecutor rejected task for flow=" + flow.getName()); |
| 94 | } |
| 95 | |
| 96 | } |
| 97 | |
| 98 | Collection<FlowExecution> results = new ArrayList<FlowExecution>(); |
| 99 | |
| 100 | // Could use a CompletionService here? |
| 101 | for (Future<FlowExecution> task : tasks) { |
| 102 | try { |
| 103 | results.add(task.get()); |
| 104 | } |
| 105 | catch (ExecutionException e) { |
| 106 | // Unwrap the expected exceptions |
| 107 | Throwable cause = e.getCause(); |
| 108 | if (cause instanceof Exception) { |
| 109 | throw (Exception) cause; |
| 110 | } else { |
| 111 | throw e; |
| 112 | } |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | return aggregator.aggregate(results); |
| 117 | |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * (non-Javadoc) |
| 122 | * |
| 123 | * @see org.springframework.batch.core.job.flow.State#isEndState() |
| 124 | */ |
| 125 | public boolean isEndState() { |
| 126 | return false; |
| 127 | } |
| 128 | } |