org.toobsframework.management.MemoryMonitor.java Source code

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Here is the source code for org.toobsframework.management.MemoryMonitor.java

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/*
 * This file is licensed to the Toobs Framework Group under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The Toobs Framework Group 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.toobsframework.management;

import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.lang.management.MemoryNotificationInfo;
import java.lang.management.MemoryPoolMXBean;
import java.lang.management.MemoryUsage;
import java.util.HashMap;
import java.util.Map;

import javax.management.Notification;
import javax.management.NotificationBroadcaster;
import javax.management.NotificationListener;
import javax.management.openmbean.CompositeData;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class MemoryMonitor {

    private static Log log = LogFactory.getLog(MemoryMonitor.class);

    private static final Map<String, MemoryPoolMXBean> memPools = new HashMap<String, MemoryPoolMXBean>();
    private static MemoryMonitor instance;

    private MemoryMonitor() {
        init();
    }

    public static MemoryMonitor getInstance() {
        if (instance == null) {
            instance = new MemoryMonitor();
        }
        return instance;
    }

    private static final NotificationListener listener = new NotificationListener() {
        public void handleNotification(Notification notification, Object handback) {
            if (MemoryNotificationInfo.MEMORY_THRESHOLD_EXCEEDED.equals(notification.getType())) {
                CompositeData cd = (CompositeData) notification.getUserData();
                MemoryNotificationInfo info = MemoryNotificationInfo.from(cd);
                MemoryUsage memUsage = info.getUsage();
                String poolName = info.getPoolName();
                System.out.printf("Notification: %s, count=%d, usage=[%s]%n", poolName, info.getCount(), memUsage);
                MemoryPoolMXBean memPool = memPools.get(poolName);
                setUsageThreshold(memPool, 0.85);
            }
        }
    };

    public static void setUsageThreshold(MemoryPoolMXBean memPool, double percentage) {
        MemoryUsage memUsage = memPool.getUsage();
        long max = memUsage.getMax();
        memPool.setUsageThreshold((long) (max * percentage));
    }

    private void init() {
        MemoryMXBean mem = ManagementFactory.getMemoryMXBean();
        ((NotificationBroadcaster) mem).addNotificationListener(listener, null, null);

        for (MemoryPoolMXBean memPool : ManagementFactory.getMemoryPoolMXBeans()) {
            if (memPool.isUsageThresholdSupported()) {
                memPools.put(memPool.getName(), memPool);
                log.info("Putting Pool " + memPool.getName());
                setUsageThreshold(memPool, 0.7);
            }
        }
    }
}