org.openmrs.util.MemoryLeakUtil.java Source code

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Here is the source code for org.openmrs.util.MemoryLeakUtil.java

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/**
 * This Source Code Form is subject to the terms of the Mozilla Public License,
 * v. 2.0. If a copy of the MPL was not distributed with this file, You can
 * obtain one at http://mozilla.org/MPL/2.0/. OpenMRS is also distributed under
 * the terms of the Healthcare Disclaimer located at http://openmrs.org/license.
 *
 * Copyright (C) OpenMRS Inc. OpenMRS is a registered trademark and the OpenMRS
 * graphic logo is a trademark of OpenMRS Inc.
 */
package org.openmrs.util;

import java.lang.reflect.Field;
import java.util.Timer;

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

import sun.net.www.http.KeepAliveCache;

/**
 * Utility functions to clean up causes of memory leakages.
 */
public class MemoryLeakUtil {

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

    //http://bugs.mysql.com/bug.php?id=36565
    public static void shutdownMysqlCancellationTimer() {
        try {
            ClassLoader myClassLoader = MemoryLeakUtil.class.getClassLoader();
            Class<?> clazz = Class.forName("com.mysql.jdbc.ConnectionImpl", false, myClassLoader);

            if (!(clazz.getClassLoader() == myClassLoader)) {
                log.info("MySQL ConnectionImpl was loaded with another ClassLoader: (" + clazz.getClassLoader()
                        + "): cancelling anyway");
            } else {
                log.info("MySQL ConnectionImpl was loaded with the WebappClassLoader: cancelling the Timer");
            }

            Field f = clazz.getDeclaredField("cancelTimer");
            f.setAccessible(true);
            Timer timer = (Timer) f.get(null);
            timer.cancel();
            log.info("completed timer cancellation");
        } catch (ClassNotFoundException cnfe) {
            // Ignore
            log.error("Cannot cancel", cnfe);
        } catch (NoSuchFieldException nsfe) {
            // Ignore
            log.error("Cannot cancel", nsfe);
        } catch (SecurityException se) {
            log.info("Failed to shut-down MySQL Statement Cancellation Timer due to a SecurityException", se);
        } catch (IllegalAccessException iae) {
            log.info("Failed to shut-down MySQL Statement Cancellation Timer due to an IllegalAccessException",
                    iae);
        }
    }

    public static void shutdownKeepAliveTimer() {
        try {
            final Field kac = HttpClient.class.getDeclaredField("kac");

            kac.setAccessible(true);
            final Field keepAliveTimer = KeepAliveCache.class.getDeclaredField("keepAliveTimer");

            keepAliveTimer.setAccessible(true);

            final Thread thread = (Thread) keepAliveTimer.get(kac.get(null));

            if (thread.getContextClassLoader() == OpenmrsClassLoader.getInstance()) {
                //Set to system class loader such that we can be garbage collected.
                thread.setContextClassLoader(ClassLoader.getSystemClassLoader());
            }
        } catch (final Exception e) {
            log.error(e.getMessage(), e);
        }
    }
}