/*
    * Copyright 2006-2011 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.builder;
  
  import org.springframework.batch.core.Job;
  import org.springframework.batch.core.Step;
  import org.springframework.batch.core.launch.JobLauncher;
  import org.springframework.batch.core.launch.support.SimpleJobLauncher;
  import org.springframework.batch.core.step.job.JobParametersExtractor;
  import org.springframework.batch.core.step.job.JobStep;
  
  /**
   * A step builder for {@link JobStep} instances. A job step executes a nested {@link Job} with parameters taken from the
   * parent job or from the step execution.
   * 
   * @author Dave Syer
   * 
   * @since 2.2
   */
  public class JobStepBuilder extends StepBuilderHelper<JobStepBuilder> {
  
  	private Job job;
  
  	private JobLauncher jobLauncher;
  
  	private JobParametersExtractor jobParametersExtractor;
  
  	/**
  	 * Create a new builder initialized with any properties in the parent. The parent is copied, so it can be re-used.
  	 * 
  	 * @param parent a parent helper containing common step properties
  	 */
  	public JobStepBuilder(StepBuilderHelper<?> parent) {
  		super(parent);
  	}
  
  	/**
  	 * Provide a job to execute during the step.
  	 * 
  	 * @param job the job to execute
  	 * @return this for fluent chaining
  	 */
  	public JobStepBuilder job(Job job) {
  		this.job = job;
  		return this;
  	}
  
  	/**
  	 * Add a job launcher. Defaults to a simple job launcher.
  	 * 
  	 * @param jobLauncher the job launcher to use
  	 * @return this for fluent chaining
  	 */
  	public JobStepBuilder launcher(JobLauncher jobLauncher) {
  		this.jobLauncher = jobLauncher;
  		return this;
  	}
  
  	/**
  	 * Provide a job parameters extractor. Useful for extracting job parameters from the parent step execution context
  	 * or job parameters.
  	 * 
  	 * @param jobParametersExtractor the job parameters extractor to use
  	 * @return this for fluent chaining
  	 */
  	public JobStepBuilder parametersExtractor(JobParametersExtractor jobParametersExtractor) {
  		this.jobParametersExtractor = jobParametersExtractor;
  		return this;
  	}
  
  	/**
  	 * Build a step from the job provided.
  	 * 
  	 * @return a new job step
  	 */
  	public Step build() {
  
  		JobStep step = new JobStep();
  		step.setName(getName());
  		super.enhance(step);
  		if (job != null) {
  			step.setJob(job);
  		}
  		if (jobParametersExtractor != null) {
  			step.setJobParametersExtractor(jobParametersExtractor);
  		}
 		if (jobLauncher == null) {
 			SimpleJobLauncher jobLauncher = new SimpleJobLauncher();
 			jobLauncher.setJobRepository(getJobRepository());
 			try {
 				jobLauncher.afterPropertiesSet();
 			}
 			catch (Exception e) {
 				throw new StepBuilderException(e);
 			}
 			this.jobLauncher = jobLauncher;
 		}
 		step.setJobLauncher(jobLauncher);
 		try {
 			step.afterPropertiesSet();
 		}
 		catch (Exception e) {
 			throw new StepBuilderException(e);
 		}
 		return step;
 
 	}
 
 }