/*
* Copyright 2006-2013 the original author or authors.
*
* 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 org.springframework.batch.core.partition.support;
import org.springframework.batch.core.BatchStatus;
import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.partition.PartitionHandler;
import org.springframework.batch.core.step.StepHolder;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Required;
import org.springframework.core.task.SyncTaskExecutor;
import org.springframework.core.task.TaskExecutor;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.util.Assert;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
/**
* A {@link PartitionHandler} that uses a {@link TaskExecutor} to execute the
* partitioned {@link Step} locally in multiple threads. This can be an
* effective approach for scaling batch steps that are IO intensive, like
* directory and filesystem scanning and copying.
* <br>
* By default, the thread pool is synchronous.
*
* @author Sebastien Gerard
* @author Dave Syer
* @since 2.0
*/
public class TaskExecutorPartitionHandler extends AbstractPartitionHandler implements StepHolder, InitializingBean {
private TaskExecutor taskExecutor = new SyncTaskExecutor();
private Step step;
@Override
public void afterPropertiesSet() throws Exception {
}
/**
* Setter for the {@link TaskExecutor} that is used to farm out step
* executions to multiple threads.
* @param taskExecutor a {@link TaskExecutor}
*/
public void setTaskExecutor(TaskExecutor taskExecutor) {
this.taskExecutor = taskExecutor;
}
/**
* Setter for the {@link Step} that will be used to execute the partitioned
* {@link StepExecution}. This is a regular Spring Batch step, with all the
* business logic required to complete an execution based on the input
* parameters in its {@link StepExecution} context.
*
* @param step the {@link Step} instance to use to execute business logic
*/
@Required
public void setStep(Step step) {
this.step = step;
}
/**
* The step instance that will be executed in parallel by this handler.
*
* @return the step instance that will be used
* @see StepHolder#getStep()
*/
@Override
public Step getStep() {
return this.step;
}
@Override
protected Set<StepExecution> doHandle(StepExecution masterStepExecution,
Set<StepExecution> partitionStepExecutions) throws Exception {
Assert.notNull(step, "A Step must be provided.");
final Set<Future<StepExecution>> tasks = new HashSet<Future<StepExecution>>(getGridSize());
final Set<StepExecution> result = new HashSet<StepExecution>();
for (final StepExecution stepExecution : partitionStepExecutions) {
final FutureTask<StepExecution> task = createTask(step, stepExecution);
try {
taskExecutor.execute(task);
tasks.add(task);
} catch (TaskRejectedException e) {
// couldn't execute one of the tasks
ExitStatus exitStatus = ExitStatus.FAILED
.addExitDescription("TaskExecutor rejected the task for this step.");
/*
* Set the status in case the caller is tracking it through the
* JobExecution.
*/
stepExecution.setStatus(BatchStatus.FAILED);
stepExecution.setExitStatus(exitStatus);
result.add(stepExecution);
}
}
for (Future<StepExecution> task : tasks) {
result.add(task.get());
}
return result;
}
/**
* Creates the task executing the given step in the context of the given execution.
*
* @param step the step to execute
* @param stepExecution the given execution
* @return the task executing the given step
*/
protected FutureTask<StepExecution> createTask(final Step step,
final StepExecution stepExecution) {
return new FutureTask<StepExecution>(new Callable<StepExecution>() {
@Override
public StepExecution call() throws Exception {
step.execute(stepExecution);
return stepExecution;
}
});
}
}