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package com.sun.enterprise.server;
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.sun.logging.LogDomains;
import com.sun.enterprise.admin.server.core.channel.ReconfigHelper;
/**
* Monitors dynamic reload files for applications and stand alone modules
* from the server runtime.
*
* @atuthor Nazrul Islam
* @since JDK 1.4
*/
class ReloadMonitor extends AbstractMonitor {
/** name of the file that user will update time stamp to trigger a reload */
static final String RELOAD_FILE = ".reload";
static final Logger _logger = LogDomains.getLogger(LogDomains.CORE_LOGGER);
/** singleton instance */
private static ReloadMonitor _instance = null;
/**
* Constructor - prohibits anyone from constructing this object.
*
* @param pollInterval polling interval
*/
private ReloadMonitor(long pollInterval) {
super(pollInterval);
}
/**
* Returns the singleton instance. If the object was not created already,
* it uses the given polling interval.
*
* @param pollInterval polling interval
*/
static synchronized ReloadMonitor getInstance(long pollInterval) {
if (_instance == null) {
_instance = new ReloadMonitor(pollInterval);
}
return _instance;
}
/**
* Removes the given application or stand alone module from the
* monitored list.
*
* @param id registration name of application
*
* @return true if removed successfully
*/
boolean removeMonitoredEntry(String id) {
boolean removed = false;
// returns false if application name is null
if (id == null) {
return removed;
}
synchronized (this._monitoredEntries) {
Iterator iter = this._monitoredEntries.iterator();
while (iter.hasNext()) {
MonitorableEntry entry = (MonitorableEntry) iter.next();
if ( id.equals(entry.getId()) ) {
this._monitoredEntries.remove(entry);
removed = true;
break;
}
}
}
return removed;
}
/**
* This method gets called from the monitor thread. This goes through
* all the monitored entried and checks the time stamps. If any of the
* time stamps is modified, it makes a callback to its listener. The
* callbacks are single threaded, i.e., waits for one to finish before
* makes the second call.
*
* <p> The time stamp of the monitored entry is set to the current
* time stamp before the callback is made.
*/
public void run() {
try {
ArrayList reloadList = new ArrayList();
synchronized (_monitoredEntries) {
Iterator iter = _monitoredEntries.iterator();
MonitorableEntry entry = null;
while (iter.hasNext()) {
entry = (MonitorableEntry) iter.next();
File file = entry.getMonitoredFile();
long lastModified = file.lastModified();
long lastReloadedAt = entry.getLastReloadedTimeStamp();
// time stamp is updated
if (lastModified > lastReloadedAt) {
// sets the time stamp so that it gets called once
entry.setLastReloadedTimeStamp(lastModified);
reloadList.add(entry);
}
}
}
// found some entries with modified time stamp
if (reloadList.size() > 0) {
_logger.log(Level.FINEST,
"[ReloadMonitor] Monitor detected reloadable entry!");
int size = reloadList.size();
MonitorableEntry entry = null;
for (int i=0; i<size; i++) {
entry = (MonitorableEntry) reloadList.get(i);
MonitorListener l = entry.getListener();
// calls back the listener
boolean success = l.reload(entry);
// log status
if (success) {
_logger.log(Level.INFO,
"core.application_reload_successful",
entry.getDisplayName());
} else {
_logger.log(Level.INFO,
"core.application_reload_failed",
entry.getDisplayName());
}
}
// Reload the web modules
/*
* Remove compile time dependence on J2EERunner. Replace it
* temporarily with call to ReconfigHelper.
J2EERunner.requestReconfiguration();
*/
ReconfigHelper.sendReconfigMessage("");
// removes all the entries after the call back
reloadList.clear();
}
} catch (Throwable t) {
// catches any uncaught exceptions thrown from the handlers
_logger.log(Level.WARNING, "core.exception", t);
}
}
} |
