com.techempower.gemini.event.CacheResetEvent Maven / Gradle / Ivy
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package com.techempower.gemini.event;
import java.util.*;
import com.techempower.gemini.*;
import com.techempower.helper.*;
import com.techempower.scheduler.*;
import com.techempower.util.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A simple event that can be used to purge the application's cache every few
* hours. Primarily meant to force synchronization between peer applications
* in a server cluster in case there are problems with the distributor. Can
* also be extended to perform other sorts of synchronization if needed, such
* as re-indexing.
*
* The interval for this event is relative to the start of the current day.
* What this means is that if the interval is set to 6 hours then it will run
* at 12am, 6am, 12pm, and 6pm regardless of when the application actually
* started up.
*
* To add this event to your application you can do something similar to the
* following in your cache class:
*
* protected CacheResetEvent resetEvent;
*
* public YourCache(YourApplication application, ConnectorFactory connectorFactory)
* {
* super(application, connectorFactory);
*
* this.resetEvent = new CacheResetEvent(application);
* }
*
* Note: Depends on the application scheduler reference to be the same as the
* infrastructure reference.
*/
public class CacheResetEvent
extends ScheduledEvent
implements Configurable
{
public static final String PROPS_PREFIX = "CacheReset.";
public static final String PROPS_INTERVAL = "IntervalHours";
public static final String PROPS_ENABLED = "Enabled";
public static final String PROPS_NOTIFY = "NotifyPeers";
public static final int DEFAULT_INTERVAL = 24;
private int interval = DEFAULT_INTERVAL;
private boolean notifyListeners = false;
private final GeminiApplication application;
private final Logger log = LoggerFactory.getLogger(getClass());
/**
* Constructor.
*/
public CacheResetEvent(GeminiApplication application)
{
super("Cache Reset Event", "Fully resets the application cache.");
this.application = application;
application.getConfigurator().addConfigurable(this);
}
/**
* Configures this event. This method will also schedule itself using the application's scheduler.
*/
@Override
public void configure(EnhancedProperties props)
{
this.interval = props.getInt(PROPS_PREFIX + PROPS_INTERVAL, this.interval);
setEnabled(props.getBoolean(PROPS_PREFIX + PROPS_ENABLED, isEnabled()));
this.notifyListeners = props.getBoolean(PROPS_PREFIX + PROPS_NOTIFY, this.notifyListeners);
// Schedule self
this.application.getScheduler().scheduleEvent(this);
}
/**
* Gets the initial scheduled time.
*/
@Override
public long getDefaultScheduledTime()
{
Calendar scheduledTime = DateHelper.getCalendarInstance();
int eventHour = this.interval;
int currentHour = scheduledTime.get(Calendar.HOUR_OF_DAY);
// If the current hour is after the first interval slot find the next slot after now
if (currentHour >= eventHour)
{
eventHour = this.interval * ((currentHour / this.interval) + 1);
}
scheduledTime.set(Calendar.HOUR_OF_DAY, eventHour);
scheduledTime.set(Calendar.MINUTE, 0);
scheduledTime.set(Calendar.SECOND, 0);
return scheduledTime.getTimeInMillis();
}
@Override
public void execute(Scheduler scheduler, boolean onDemandExecution)
{
if (isEnabled())
{
this.doReset();
}
scheduler.scheduleEvent(this, this.getNextRunTime());
}
/**
* Gets the next time to run this event.
*/
public long getNextRunTime()
{
Calendar next = DateHelper.getCalendarInstance();
next.add(Calendar.HOUR, this.interval);
next.set(Calendar.MINUTE, 0);
next.set(Calendar.SECOND, 0);
return (next.getTimeInMillis());
}
/**
* Performs the actual resetting.
* Extend this to reset additional resources.
*/
protected void doReset()
{
this.log.info("Performing full cache reset");
this.application.getStore().reset(this.notifyListeners, false);
}
}