/*
* Copyright 2006-2008 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.step.job;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.UnexpectedJobExecutionException;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.step.AbstractStep;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.util.Assert;
/**
* A {@link Step} that delegates to a {@link Job} to do its work. This is a
* great tool for managing dependencies between jobs, and also to modularise
* complex step logic into something that is testable in isolation. The job is
* executed with parameters that can be extracted from the step execution, hence
* this step can also be usefully used as the worker in a parallel or
* partitioned execution.
*
* @author Dave Syer
*
*/
public class JobStep extends AbstractStep {
/**
* The key for the job parameters in the step execution context. Needed for
* restarts.
*/
private static final String JOB_PARAMETERS_KEY = JobStep.class.getName() + ".JOB_PARAMETERS";
private Job job;
private JobLauncher jobLauncher;
private JobParametersExtractor jobParametersExtractor = new DefaultJobParametersExtractor();
@Override
public void afterPropertiesSet() throws Exception {
super.afterPropertiesSet();
Assert.state(jobLauncher != null, "A JobLauncher must be provided");
Assert.state(job != null, "A Job must be provided");
}
/**
* The {@link Job} to delegate to in this step.
*
* @param job a {@link Job}
*/
public void setJob(Job job) {
this.job = job;
}
/**
* A {@link JobLauncher} is required to be able to run the enclosed
* {@link Job}.
*
* @param jobLauncher the {@link JobLauncher} to set
*/
public void setJobLauncher(JobLauncher jobLauncher) {
this.jobLauncher = jobLauncher;
}
/**
* The {@link JobParametersExtractor} is used to extract
* {@link JobParametersExtractor} from the {@link StepExecution} to run the
* {@link Job}. By default an instance will be provided that simply copies
* the {@link JobParameters} from the parent job.
*
* @param jobParametersExtractor the {@link JobParametersExtractor} to set
*/
public void setJobParametersExtractor(JobParametersExtractor jobParametersExtractor) {
this.jobParametersExtractor = jobParametersExtractor;
}
/**
* Execute the job provided by delegating to the {@link JobLauncher} to
* prevent duplicate executions. The job parameters will be generated by the
* {@link JobParametersExtractor} provided (if any), otherwise empty. On a
* restart, the job parameters will be the same as the last (failed)
* execution.
*
* @see AbstractStep#doExecute(StepExecution)
*/
@Override
protected void doExecute(StepExecution stepExecution) throws Exception {
ExecutionContext executionContext = stepExecution.getExecutionContext();
executionContext.put(STEP_TYPE_KEY, this.getClass().getName());
JobParameters jobParameters;
if (executionContext.containsKey(JOB_PARAMETERS_KEY)) {
jobParameters = (JobParameters) executionContext.get(JOB_PARAMETERS_KEY);
}
else {
jobParameters = jobParametersExtractor.getJobParameters(job, stepExecution);
executionContext.put(JOB_PARAMETERS_KEY, jobParameters);
}
JobExecution jobExecution = jobLauncher.run(job, jobParameters);
if (jobExecution.getStatus().isUnsuccessful()) {
// AbstractStep will take care of the step execution status
throw new UnexpectedJobExecutionException("Step failure: the delegate Job failed in JobStep.");
}
}
}