http://www.eclipse.org/platform: Common Eclipse Runtime (Eclipse Foundation) 
Copyright (c) 2009, 2010 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation

/*******************************************************************************
 * Copyright (c) 2009, 2010 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.equinox.events;


Defines constants for memory event handlers.  A memory event handler implements
the org.osgi.service.event.EventHandler interface as specified by the OSGi 
Event Admin Service Specification.


For example, the following handler is registered to handle critical memory
events:

BundleContext context = getContext();
EventHandler handler = getHandler();
Hashtable ht = new Hashtable();
ht.put(EventConstants.EVENT_TOPIC, MemoryEventConstants.TOPIC_CRITICAL);
context.registerService(EventHandler.class.getName(), handler, ht);


There is no policy implemented for sending memory events in Equinox or
Eclipse by default.  Another bundle must implement the policy that determines
when to send memory events.  This policy must use the Event Admin Service
to fire memory events to the registered handlers.



Since:3.6
/**
 * Defines constants for memory event handlers.  A memory event handler implements
 * the <code>org.osgi.service.event.EventHandler</code> interface as specified by the OSGi 
 * Event Admin Service Specification.
 * <p>
 * For example, the following handler is registered to handle critical memory
 * events:
 * <pre>
 * BundleContext context = getContext();
 * EventHandler handler = getHandler();
 * Hashtable ht = new Hashtable();
 * ht.put(EventConstants.EVENT_TOPIC, MemoryEventConstants.TOPIC_CRITICAL);
 * context.registerService(EventHandler.class.getName(), handler, ht);
 * </pre>
 * There is no policy implemented for sending memory events in Equinox or
 * Eclipse by default.  Another bundle must implement the policy that determines
 * when to send memory events.  This policy must use the Event Admin Service
 * to fire memory events to the registered handlers.
 * </p>
 * @since 3.6
 */
public final class MemoryEventConstants {
	private MemoryEventConstants() {
		// prevent construction.
	}

	
The base topic that all memory events use.

/**
	 * The base topic that all memory events use.
	 */
	public static final String TOPIC_BASE = "org/eclipse/equinox/events/MemoryEvent/"; //$NON-NLS-1$

	
A memory event topic for normal memory events.
Indicates memory is running low at the lowest severity.
Listeners are requested to release caches that can easily be recomputed.
The Java VM is not seriously in trouble, but process size is getting higher than 
is deemed acceptable.

/**
	 * A memory event topic for normal memory events.
	 * Indicates memory is running low at the lowest severity.
	 * Listeners are requested to release caches that can easily be recomputed.
	 * The Java VM is not seriously in trouble, but process size is getting higher than 
	 * is deemed acceptable.
	 */
	public static final String TOPIC_NORMAL = TOPIC_BASE + "NORMAL"; //$NON-NLS-1$

	
A memory event topic for serious memory events.
Indicates memory is running low at medium severity. 
Listeners are requested to release complex intermediate models
(.e.g. intermediate build results).
Memory is getting low and may cause operating system level stress, such as swapping.

/**
	 * A memory event topic for serious memory events.
	 * Indicates memory is running low at medium severity. 
	 * Listeners are requested to release complex intermediate models
	 * (.e.g. intermediate build results).
	 * Memory is getting low and may cause operating system level stress, such as swapping.
	 */
	public static final String TOPIC_SERIOUS = TOPIC_BASE + "SERIOUS"; //$NON-NLS-1$

	
A memory event topic for critical memory events.
Indicates memory is running low at highest severity.
Listeners are requested to do what ever is possible to free memory.
Things like free in memory caches, close editors and perspectives, 
close database connections, etc.
Restoring these resources and caches constitutes lots of work, but
memory is so low that drastic measures are required.

/**
	 * A memory event topic for critical memory events.
	 * Indicates memory is running low at highest severity.
	 * Listeners are requested to do what ever is possible to free memory.
	 * Things like free in memory caches, close editors and perspectives, 
	 * close database connections, etc.
	 * Restoring these resources and caches constitutes lots of work, but
	 * memory is so low that drastic measures are required.
	 */

	public static final String TOPIC_CRITICAL = TOPIC_BASE + "CRITICAL"; //$NON-NLS-1$

	
A memory event topic for all memory events.

/**
	 * A memory event topic for all memory events.
	 */
	public static final String TOPIC_ALL = TOPIC_BASE + "*"; //$NON-NLS-1$
}