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Quartz Enterprise Job Scheduler - additional library of ready to use Jobs
/*
* All content copyright Terracotta, Inc., unless otherwise indicated. All rights reserved.
*
* 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.quartz.jobs;
import java.io.File;
import java.net.URL;
import java.net.URLDecoder;
import org.quartz.DisallowConcurrentExecution;
import org.quartz.Job;
import org.quartz.JobDataMap;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.PersistJobDataAfterExecution;
import org.quartz.SchedulerContext;
import org.quartz.SchedulerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Inspects a file and compares whether it's "last modified date" has changed
* since the last time it was inspected. If the file has been updated, the
* job invokes a "call-back" method on an identified
* FileScanListener that can be found in the
* SchedulerContext.
*
* @author jhouse
* @author pl47ypus
* @see org.quartz.jobs.FileScanListener
*/
@DisallowConcurrentExecution
@PersistJobDataAfterExecution
public class FileScanJob implements Job {
/**
* JobDataMap key with which to specify
* the name of the file to monitor.
*/
public static final String FILE_NAME = "FILE_NAME";
/**
* JobDataMap key with which to specify the
* {@link org.quartz.jobs.FileScanListener} to be
* notified when the file contents change.
*/
public static final String FILE_SCAN_LISTENER_NAME = "FILE_SCAN_LISTENER_NAME";
/**
* JobDataMap key with which to specify a long
* value that represents the minimum number of milliseconds that must have
* past since the file's last modified time in order to consider the file
* new/altered. This is necessary because another process may still be
* in the middle of writing to the file when the scan occurs, and the
* file may therefore not yet be ready for processing.
*
* If this parameter is not specified, a default value of
* 5000 (five seconds) will be used.
*/
public static final String MINIMUM_UPDATE_AGE = "MINIMUM_UPDATE_AGE";
private static final String LAST_MODIFIED_TIME = "LAST_MODIFIED_TIME";
private final Logger log = LoggerFactory.getLogger(getClass());
public FileScanJob() {
}
/**
* @see org.quartz.Job#execute(org.quartz.JobExecutionContext)
*/
public void execute(JobExecutionContext context) throws JobExecutionException {
JobDataMap mergedJobDataMap = context.getMergedJobDataMap();
SchedulerContext schedCtxt = null;
try {
schedCtxt = context.getScheduler().getContext();
} catch (SchedulerException e) {
throw new JobExecutionException("Error obtaining scheduler context.", e, false);
}
String fileName = mergedJobDataMap.getString(FILE_NAME);
String listenerName = mergedJobDataMap.getString(FILE_SCAN_LISTENER_NAME);
if(fileName == null) {
throw new JobExecutionException("Required parameter '" +
FILE_NAME + "' not found in merged JobDataMap");
}
if(listenerName == null) {
throw new JobExecutionException("Required parameter '" +
FILE_SCAN_LISTENER_NAME + "' not found in merged JobDataMap");
}
FileScanListener listener = (FileScanListener)schedCtxt.get(listenerName);
if(listener == null) {
throw new JobExecutionException("FileScanListener named '" +
listenerName + "' not found in SchedulerContext");
}
long lastDate = -1;
if(mergedJobDataMap.containsKey(LAST_MODIFIED_TIME)) {
lastDate = mergedJobDataMap.getLong(LAST_MODIFIED_TIME);
}
long minAge = 5000;
if(mergedJobDataMap.containsKey(MINIMUM_UPDATE_AGE)) {
minAge = mergedJobDataMap.getLong(MINIMUM_UPDATE_AGE);
}
long maxAgeDate = System.currentTimeMillis() + minAge;
long newDate = getLastModifiedDate(fileName);
if(newDate < 0) {
log.warn("File '"+fileName+"' does not exist.");
return;
}
if(lastDate > 0 && (newDate > lastDate && newDate < maxAgeDate)) {
// notify call back...
log.info("File '"+fileName+"' updated, notifying listener.");
listener.fileUpdated(fileName);
} else if (log.isDebugEnabled()) {
log.debug("File '"+fileName+"' unchanged.");
}
// It is the JobDataMap on the JobDetail which is actually stateful
context.getJobDetail().getJobDataMap().put(LAST_MODIFIED_TIME, newDate);
}
protected long getLastModifiedDate(String fileName) {
URL resource = Thread.currentThread().getContextClassLoader().getResource(fileName);
// Get the absolute path.
String filePath = (resource == null) ? fileName : URLDecoder.decode(resource.getFile()); ;
// If the jobs file is inside a jar point to the jar file (to get it modification date).
// Otherwise continue as usual.
int jarIndicator = filePath.indexOf('!');
if (jarIndicator > 0) {
filePath = filePath.substring(5, filePath.indexOf('!'));
}
File file = new File(filePath);
if(!file.exists()) {
return -1;
} else {
return file.lastModified();
}
}
}