gui/servlet/embedded/src/main/java/org/apache/batchee/servlet/SimpleRestController.java - geronimo-batchee - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You 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.apache.batchee.servlet;

 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
 import java.util.Properties;

 import javax.batch.operations.JobExecutionAlreadyCompleteException;
 import javax.batch.operations.JobExecutionNotRunningException;
 import javax.batch.operations.JobOperator;
 import javax.batch.operations.JobStartException;
 import javax.batch.operations.NoSuchJobExecutionException;
 import javax.batch.runtime.BatchStatus;
 import javax.batch.runtime.JobExecution;
 import javax.batch.runtime.Metric;
 import javax.batch.runtime.StepExecution;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 /**
  * Simple REST api for JBatch
  */
 public class SimpleRestController {
     public static final String REST_CONTENT_TYPE = "text/plain";
     public static final String NOT_FOUND_STRING = "-";
     public static final char CSV_DELIMITER = ';';

     public static final String OP_START = "start/";
     public static final String OP_STATUS = "status/";
     public static final String OP_METRICS = "metrics/";

     public static final String OP_STOP = "stop/";
     public static final String OP_RESTART = "restart/";
     public static final long NO_JOB_ID = -1L;

     private final JobOperator jobOperator;

     public SimpleRestController(JobOperator jobOperator) {
         this.jobOperator = jobOperator;
     }


     /**
      * The main entry for the simple REST handling
      */
     public void dispatch(HttpServletRequest req, HttpServletResponse resp, String path) {
         resp.setContentType(REST_CONTENT_TYPE);

         if (path != null && path.startsWith(OP_START)) {
             startBatch(path.substring(OP_START.length()), req, resp);
         } else if (path != null && path.startsWith(OP_STATUS)) {
             batchStatus(path.substring(OP_STATUS.length()), req, resp);
         } else if (path != null && path.startsWith(OP_METRICS)) {
             batchMetrics(path.substring(OP_METRICS.length()), req, resp);
         } else if (path != null && path.startsWith(OP_STOP)) {
             batchStop(path.substring(OP_STOP.length()), req, resp);
         } else if (path != null && path.startsWith(OP_RESTART)) {
             batchRestart(path.substring(OP_RESTART.length()), req, resp);
         } else {
             unknownCommand(path, resp);
         }
     }

     private void startBatch(String batchName, HttpServletRequest req, HttpServletResponse resp) {
         Properties jobProperties = extractJobProperties(req, resp);
         if (jobProperties == null) {
             return;
         }

         try {
             long jobId = jobOperator.start(batchName, jobProperties);
             reportSuccess(jobId, resp, null);
         } catch (JobStartException jobStartException) {
             StringBuilder msg = new StringBuilder("Error while starting job ");
             msg.append(batchName).append('\n');
             appendExceptionMsg(msg, jobStartException);
             reportFailure(NO_JOB_ID, resp, msg.toString());
         }
     }

     private void batchStatus(String batchId, HttpServletRequest req, HttpServletResponse resp) {
         Long executionId = extractExecutionId(batchId, resp);
         if (executionId == null) {
             return;
         }

         try {
             JobExecution jobExecution = jobOperator.getJobExecution(executionId);
             BatchStatus batchStatus = jobExecution.getBatchStatus();
             reportSuccess(executionId, resp, batchStatus.name());
         } catch (NoSuchJobExecutionException noSuchJob) {
             reportFailure(executionId, resp, "NoSuchJob");
         } catch (Exception generalException) {
             StringBuilder msg = new StringBuilder("Failure in BatchExecution");
             appendExceptionMsg(msg, generalException);
             reportFailure(executionId, resp, msg.toString());
         }
     }

     private void batchMetrics(String batchId, HttpServletRequest req, HttpServletResponse resp) {
         Long executionId = extractExecutionId(batchId, resp);
         if (executionId == null) {
             return;
         }

         try {
             JobExecution jobExecution = jobOperator.getJobExecution(executionId);
             BatchStatus batchStatus = jobExecution.getBatchStatus();

             List<StepExecution> stepExecutions = jobOperator.getStepExecutions(executionId);
             reportSuccess(executionId, resp, batchStatus.name());
             reportMetricsCsv(resp, stepExecutions);
         } catch (NoSuchJobExecutionException noSuchJob) {
             reportFailure(executionId, resp, "NoSuchJob");
         } catch (Exception generalException) {
             StringBuilder msg = new StringBuilder("Failure in BatchExecution");
             appendExceptionMsg(msg, generalException);
             reportFailure(executionId, resp, msg.toString());
         }
     }

     private void batchStop(String batchId, HttpServletRequest req, HttpServletResponse resp) {
         Long executionId = extractExecutionId(batchId, resp);
         if (executionId == null) {
             return;
         }

         try {
             jobOperator.stop(executionId);
             reportSuccess(executionId, resp, BatchStatus.STOPPING.toString());
         } catch (NoSuchJobExecutionException noSuchJob) {
             reportFailure(executionId, resp, "NoSuchJob");
         } catch (JobExecutionNotRunningException notRunningException) {
             reportFailure(executionId, resp, "JobExecutionNotRunning");
         } catch (Exception generalException) {
             StringBuilder msg = new StringBuilder("Failure in BatchExecution");
             appendExceptionMsg(msg, generalException);
             reportFailure(executionId, resp, msg.toString());
         }
     }

     private void batchRestart(String batchId, HttpServletRequest req, HttpServletResponse resp) {
         Long executionId = extractExecutionId(batchId, resp);
         if (executionId == null) {
             return;
         }

         Properties jobProperties = extractJobProperties(req, resp);

         try {
             jobOperator.restart(executionId, jobProperties);
         } catch (NoSuchJobExecutionException noSuchJob) {
             reportFailure(executionId, resp, "NoSuchJob");
         } catch (JobExecutionAlreadyCompleteException alreadyCompleted) {
             reportFailure(executionId, resp, "NoSuchJob");
         } catch (Exception generalException) {
             StringBuilder msg = new StringBuilder("Failure in BatchExecution");
             appendExceptionMsg(msg, generalException);
             reportFailure(executionId, resp, msg.toString());
         }
     }


     private void unknownCommand(String path, HttpServletResponse resp) {
         StringBuilder msg = new StringBuilder("Unknown command:");
         msg.append(path).append('\n');

         msg.append("The returned response if of MIME type text/plain and contains the following information\n");
         msg.append("  {jobExecutionId} (or -1 if no executionId was detected)\\n\n");
         msg.append("  OK (or FAILURE)\\n\n");
         msg.append("  followed by command specific information\n");

         msg.append("\nKnown commands are:\n\n");
         msg.append("* ").append(OP_START).append(" - start a new batch job\n");
         msg.append("  Sample: http://localhost:8080/myapp/jbatch/rest/start/myjobname?param1=x&param2=y\n");
         msg.append("  BatchEE will start the job and immediately return\n\n");

         msg.append("* ").append(OP_STATUS).append(" - query the current status \n");
         msg.append("  Sample: http://localhost:8080/myapp/jbatch/rest/status/23\n");
         msg.append("  will return the state of executionId 23\n\n");

         msg.append("* ").append(OP_METRICS).append(" - query the current metrics \n");
         msg.append("  Sample: http://localhost:8080/myapp/jbatch/rest/metrics/23\n");
         msg.append("  will return the metrics of executionId 23\n\n");

         msg.append("* ").append(OP_STOP).append(" - stop the job with the given executionId \n");
         msg.append("  Sample: http://localhost:8080/myapp/jbatch/rest/stop/23\n");
         msg.append("  will stop the job with executionId 23\n\n");

         msg.append("* ").append(OP_RESTART).append(" - restart the job with the given executionId \n");
         msg.append("  Sample: http://localhost:8080/myapp/jbatch/rest/restart/23\n");
         msg.append("  will restart the job with executionId 23\n\n");

         reportFailure(NO_JOB_ID, resp, msg.toString());
     }

     private Properties extractJobProperties(HttpServletRequest req, HttpServletResponse resp) {
         Properties jobProperties = new Properties();
         Map<String, String[]> parameterMap = req.getParameterMap();
         for (Map.Entry<String, String[]> paramEntry : parameterMap.entrySet()) {
             String key = paramEntry.getKey();
             if (key == null || key.length() == 0) {
                 reportFailure(NO_JOB_ID, resp, "Parameter key must be set");
                 return null;
             }

             String[] vals = paramEntry.getValue();
             if (vals == null || vals.length != 1) {
                 reportFailure(NO_JOB_ID, resp, "Exactly one value must be set for each parameter (parameter name=" + key + ")");
                 return null;
             }
             String val = vals[0];
             jobProperties.put(key, val);
         }
         return jobProperties;
     }

     private Long extractExecutionId(String batchId, HttpServletResponse resp) {
         if (batchId == null || batchId.isEmpty()) {
             reportFailure(NO_JOB_ID, resp, "no executionId given");
             return null;
         }

         try {
             return Long.valueOf(batchId);
         } catch(NumberFormatException nfe) {
             reportFailure(NO_JOB_ID, resp, "executionId must be numeric, but is " + batchId);
             return null;
         }
     }

     private void reportSuccess(long jobId, HttpServletResponse resp, String msg) {
         resp.setStatus(HttpServletResponse.SC_OK);
         writeContent(resp, Long.toString(jobId) + "\n");
         writeContent(resp, "OK\n");
         if (msg != null) {
             writeContent(resp, msg);
         }
     }

     private void reportFailure(long jobId, HttpServletResponse resp, String content) {
         resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
         writeContent(resp, Long.toString(jobId) + "\n");
         writeContent(resp, "FAILURE\n");
         writeContent(resp, content);
     }

     private void reportMetricsCsv(HttpServletResponse resp, List<StepExecution> stepExecutions) {
         StringBuilder stringBuilder = new StringBuilder(200);
         stringBuilder.append("\n");

         // append csv header to stringbuilder
         joinCsv(stringBuilder, Arrays.asList("STEP_EXECUTION_ID", "STEP_NAME"));
         stringBuilder.append(CSV_DELIMITER);
         joinCsv(stringBuilder, Arrays.asList(Metric.MetricType.values()));
         stringBuilder.append("\n");

         Collections.sort(stepExecutions, new Comparator<StepExecution>() {
             @Override
             public int compare(StepExecution o1, StepExecution o2) {
                 return Long.compare(o1.getStepExecutionId(), o2.getStepExecutionId());
             }
         });
         // append csv values to stringbuilder, one stepExecution per line
         for (StepExecution stepExecution : stepExecutions) {
             stringBuilder.append(stepExecution.getStepExecutionId());
             stringBuilder.append(CSV_DELIMITER);
             stringBuilder.append(stepExecution.getStepName());
             stringBuilder.append(CSV_DELIMITER);

             Metric[] metricsArray = stepExecution.getMetrics();
             Map<Metric.MetricType, Metric> sourceMap = new HashMap<Metric.MetricType, Metric>();
             for (Metric metric : metricsArray) {
                 sourceMap.put(metric.getType(), metric);
             }

             List<String> orderedMetricsValues = new ArrayList<String>();
             for (Metric.MetricType type : Metric.MetricType.values()) {
                 orderedMetricsValues.add(sourceMap.containsKey(type) ? String.valueOf(sourceMap.get(type).getValue()) : NOT_FOUND_STRING);
             }
             joinCsv(stringBuilder, orderedMetricsValues);

             stringBuilder.append("\n");
         }

         writeContent(resp, stringBuilder.toString());
     }

     private void joinCsv(StringBuilder builder, List values) {
         for (ListIterator iter = values.listIterator(); iter.hasNext(); ) {
             builder.append(iter.next());
             if (iter.hasNext()) {
                 builder.append(CSV_DELIMITER);
             }
         }
     }

     private void writeContent(HttpServletResponse resp, String content) {
         try {
             resp.getWriter().append(content);
         } catch (IOException ioe) {
             throw new RuntimeException(ioe);
         }
     }

     private void appendExceptionMsg(StringBuilder msg, Exception exception) {
         msg.append(exception.getMessage()).append('\n');
         StringWriter sw = new StringWriter();
         exception.printStackTrace(new PrintWriter(sw));
         msg.append(sw.toString());
     }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You 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.apache.batchee.servlet;

	import java.io.IOException;
	import java.io.PrintWriter;
	import java.io.StringWriter;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.HashMap;
	import java.util.List;
	import java.util.ListIterator;
	import java.util.Map;
	import java.util.Properties;

	import javax.batch.operations.JobExecutionAlreadyCompleteException;
	import javax.batch.operations.JobExecutionNotRunningException;
	import javax.batch.operations.JobOperator;
	import javax.batch.operations.JobStartException;
	import javax.batch.operations.NoSuchJobExecutionException;
	import javax.batch.runtime.BatchStatus;
	import javax.batch.runtime.JobExecution;
	import javax.batch.runtime.Metric;
	import javax.batch.runtime.StepExecution;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	/**
	* Simple REST api for JBatch
	*/
	public class SimpleRestController {
	public static final String REST_CONTENT_TYPE = "text/plain";
	public static final String NOT_FOUND_STRING = "-";
	public static final char CSV_DELIMITER = ';';

	public static final String OP_START = "start/";
	public static final String OP_STATUS = "status/";
	public static final String OP_METRICS = "metrics/";

	public static final String OP_STOP = "stop/";
	public static final String OP_RESTART = "restart/";
	public static final long NO_JOB_ID = -1L;

	private final JobOperator jobOperator;

	public SimpleRestController(JobOperator jobOperator) {
	this.jobOperator = jobOperator;
	}


	/**
	* The main entry for the simple REST handling
	*/
	public void dispatch(HttpServletRequest req, HttpServletResponse resp, String path) {
	resp.setContentType(REST_CONTENT_TYPE);

	if (path != null && path.startsWith(OP_START)) {
	startBatch(path.substring(OP_START.length()), req, resp);
	} else if (path != null && path.startsWith(OP_STATUS)) {
	batchStatus(path.substring(OP_STATUS.length()), req, resp);
	} else if (path != null && path.startsWith(OP_METRICS)) {
	batchMetrics(path.substring(OP_METRICS.length()), req, resp);
	} else if (path != null && path.startsWith(OP_STOP)) {
	batchStop(path.substring(OP_STOP.length()), req, resp);
	} else if (path != null && path.startsWith(OP_RESTART)) {
	batchRestart(path.substring(OP_RESTART.length()), req, resp);
	} else {
	unknownCommand(path, resp);
	}
	}

	private void startBatch(String batchName, HttpServletRequest req, HttpServletResponse resp) {
	Properties jobProperties = extractJobProperties(req, resp);
	if (jobProperties == null) {
	return;
	}

	try {
	long jobId = jobOperator.start(batchName, jobProperties);
	reportSuccess(jobId, resp, null);
	} catch (JobStartException jobStartException) {
	StringBuilder msg = new StringBuilder("Error while starting job ");
	msg.append(batchName).append('\n');
	appendExceptionMsg(msg, jobStartException);
	reportFailure(NO_JOB_ID, resp, msg.toString());
	}
	}

	private void batchStatus(String batchId, HttpServletRequest req, HttpServletResponse resp) {
	Long executionId = extractExecutionId(batchId, resp);
	if (executionId == null) {
	return;
	}

	try {
	JobExecution jobExecution = jobOperator.getJobExecution(executionId);
	BatchStatus batchStatus = jobExecution.getBatchStatus();
	reportSuccess(executionId, resp, batchStatus.name());
	} catch (NoSuchJobExecutionException noSuchJob) {
	reportFailure(executionId, resp, "NoSuchJob");
	} catch (Exception generalException) {
	StringBuilder msg = new StringBuilder("Failure in BatchExecution");
	appendExceptionMsg(msg, generalException);
	reportFailure(executionId, resp, msg.toString());
	}
	}

	private void batchMetrics(String batchId, HttpServletRequest req, HttpServletResponse resp) {
	Long executionId = extractExecutionId(batchId, resp);
	if (executionId == null) {
	return;
	}

	try {
	JobExecution jobExecution = jobOperator.getJobExecution(executionId);
	BatchStatus batchStatus = jobExecution.getBatchStatus();

	List<StepExecution> stepExecutions = jobOperator.getStepExecutions(executionId);
	reportSuccess(executionId, resp, batchStatus.name());
	reportMetricsCsv(resp, stepExecutions);
	} catch (NoSuchJobExecutionException noSuchJob) {
	reportFailure(executionId, resp, "NoSuchJob");
	} catch (Exception generalException) {
	StringBuilder msg = new StringBuilder("Failure in BatchExecution");
	appendExceptionMsg(msg, generalException);
	reportFailure(executionId, resp, msg.toString());
	}
	}

	private void batchStop(String batchId, HttpServletRequest req, HttpServletResponse resp) {
	Long executionId = extractExecutionId(batchId, resp);
	if (executionId == null) {
	return;
	}

	try {
	jobOperator.stop(executionId);
	reportSuccess(executionId, resp, BatchStatus.STOPPING.toString());
	} catch (NoSuchJobExecutionException noSuchJob) {
	reportFailure(executionId, resp, "NoSuchJob");
	} catch (JobExecutionNotRunningException notRunningException) {
	reportFailure(executionId, resp, "JobExecutionNotRunning");
	} catch (Exception generalException) {
	StringBuilder msg = new StringBuilder("Failure in BatchExecution");
	appendExceptionMsg(msg, generalException);
	reportFailure(executionId, resp, msg.toString());
	}
	}

	private void batchRestart(String batchId, HttpServletRequest req, HttpServletResponse resp) {
	Long executionId = extractExecutionId(batchId, resp);
	if (executionId == null) {
	return;
	}

	Properties jobProperties = extractJobProperties(req, resp);

	try {
	jobOperator.restart(executionId, jobProperties);
	} catch (NoSuchJobExecutionException noSuchJob) {
	reportFailure(executionId, resp, "NoSuchJob");
	} catch (JobExecutionAlreadyCompleteException alreadyCompleted) {
	reportFailure(executionId, resp, "NoSuchJob");
	} catch (Exception generalException) {
	StringBuilder msg = new StringBuilder("Failure in BatchExecution");
	appendExceptionMsg(msg, generalException);
	reportFailure(executionId, resp, msg.toString());
	}
	}


	private void unknownCommand(String path, HttpServletResponse resp) {
	StringBuilder msg = new StringBuilder("Unknown command:");
	msg.append(path).append('\n');

	msg.append("The returned response if of MIME type text/plain and contains the following information\n");
	msg.append(" {jobExecutionId} (or -1 if no executionId was detected)\\n\n");
	msg.append(" OK (or FAILURE)\\n\n");
	msg.append(" followed by command specific information\n");

	msg.append("\nKnown commands are:\n\n");
	msg.append("* ").append(OP_START).append(" - start a new batch job\n");
	msg.append(" Sample: http://localhost:8080/myapp/jbatch/rest/start/myjobname?param1=x&param2=y\n");
	msg.append(" BatchEE will start the job and immediately return\n\n");

	msg.append("* ").append(OP_STATUS).append(" - query the current status \n");
	msg.append(" Sample: http://localhost:8080/myapp/jbatch/rest/status/23\n");
	msg.append(" will return the state of executionId 23\n\n");

	msg.append("* ").append(OP_METRICS).append(" - query the current metrics \n");
	msg.append(" Sample: http://localhost:8080/myapp/jbatch/rest/metrics/23\n");
	msg.append(" will return the metrics of executionId 23\n\n");

	msg.append("* ").append(OP_STOP).append(" - stop the job with the given executionId \n");
	msg.append(" Sample: http://localhost:8080/myapp/jbatch/rest/stop/23\n");
	msg.append(" will stop the job with executionId 23\n\n");

	msg.append("* ").append(OP_RESTART).append(" - restart the job with the given executionId \n");
	msg.append(" Sample: http://localhost:8080/myapp/jbatch/rest/restart/23\n");
	msg.append(" will restart the job with executionId 23\n\n");

	reportFailure(NO_JOB_ID, resp, msg.toString());
	}

	private Properties extractJobProperties(HttpServletRequest req, HttpServletResponse resp) {
	Properties jobProperties = new Properties();
	Map<String, String[]> parameterMap = req.getParameterMap();
	for (Map.Entry<String, String[]> paramEntry : parameterMap.entrySet()) {
	String key = paramEntry.getKey();
	if (key == null \|\| key.length() == 0) {
	reportFailure(NO_JOB_ID, resp, "Parameter key must be set");
	return null;
	}

	String[] vals = paramEntry.getValue();
	if (vals == null \|\| vals.length != 1) {
	reportFailure(NO_JOB_ID, resp, "Exactly one value must be set for each parameter (parameter name=" + key + ")");
	return null;
	}
	String val = vals[0];
	jobProperties.put(key, val);
	}
	return jobProperties;
	}

	private Long extractExecutionId(String batchId, HttpServletResponse resp) {
	if (batchId == null \|\| batchId.isEmpty()) {
	reportFailure(NO_JOB_ID, resp, "no executionId given");
	return null;
	}

	try {
	return Long.valueOf(batchId);
	} catch(NumberFormatException nfe) {
	reportFailure(NO_JOB_ID, resp, "executionId must be numeric, but is " + batchId);
	return null;
	}
	}

	private void reportSuccess(long jobId, HttpServletResponse resp, String msg) {
	resp.setStatus(HttpServletResponse.SC_OK);
	writeContent(resp, Long.toString(jobId) + "\n");
	writeContent(resp, "OK\n");
	if (msg != null) {
	writeContent(resp, msg);
	}
	}

	private void reportFailure(long jobId, HttpServletResponse resp, String content) {
	resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	writeContent(resp, Long.toString(jobId) + "\n");
	writeContent(resp, "FAILURE\n");
	writeContent(resp, content);
	}

	private void reportMetricsCsv(HttpServletResponse resp, List<StepExecution> stepExecutions) {
	StringBuilder stringBuilder = new StringBuilder(200);
	stringBuilder.append("\n");

	// append csv header to stringbuilder
	joinCsv(stringBuilder, Arrays.asList("STEP_EXECUTION_ID", "STEP_NAME"));
	stringBuilder.append(CSV_DELIMITER);
	joinCsv(stringBuilder, Arrays.asList(Metric.MetricType.values()));
	stringBuilder.append("\n");

	Collections.sort(stepExecutions, new Comparator<StepExecution>() {
	@Override
	public int compare(StepExecution o1, StepExecution o2) {
	return Long.compare(o1.getStepExecutionId(), o2.getStepExecutionId());
	}
	});
	// append csv values to stringbuilder, one stepExecution per line
	for (StepExecution stepExecution : stepExecutions) {
	stringBuilder.append(stepExecution.getStepExecutionId());
	stringBuilder.append(CSV_DELIMITER);
	stringBuilder.append(stepExecution.getStepName());
	stringBuilder.append(CSV_DELIMITER);

	Metric[] metricsArray = stepExecution.getMetrics();
	Map<Metric.MetricType, Metric> sourceMap = new HashMap<Metric.MetricType, Metric>();
	for (Metric metric : metricsArray) {
	sourceMap.put(metric.getType(), metric);
	}

	List<String> orderedMetricsValues = new ArrayList<String>();
	for (Metric.MetricType type : Metric.MetricType.values()) {
	orderedMetricsValues.add(sourceMap.containsKey(type) ? String.valueOf(sourceMap.get(type).getValue()) : NOT_FOUND_STRING);
	}
	joinCsv(stringBuilder, orderedMetricsValues);

	stringBuilder.append("\n");
	}

	writeContent(resp, stringBuilder.toString());
	}

	private void joinCsv(StringBuilder builder, List values) {
	for (ListIterator iter = values.listIterator(); iter.hasNext(); ) {
	builder.append(iter.next());
	if (iter.hasNext()) {
	builder.append(CSV_DELIMITER);
	}
	}
	}

	private void writeContent(HttpServletResponse resp, String content) {
	try {
	resp.getWriter().append(content);
	} catch (IOException ioe) {
	throw new RuntimeException(ioe);
	}
	}

	private void appendExceptionMsg(StringBuilder msg, Exception exception) {
	msg.append(exception.getMessage()).append('\n');
	StringWriter sw = new StringWriter();
	exception.printStackTrace(new PrintWriter(sw));
	msg.append(sw.toString());
	}

	}