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This module constrains the number of mounted archive files in order to save some heap space. It provides a JMX interface for monitoring and management. Add the JAR artifact of this module to the run time class path to make its services available for service location in the client API modules.

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/*
 * Copyright (C) 2005-2015 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package de.schlichtherle.truezip.extension.pace;

import de.schlichtherle.truezip.fs.FsManager;
import de.schlichtherle.truezip.fs.sl.FsManagerLocator;
import de.schlichtherle.truezip.fs.spi.FsManagerDecorator;
import java.lang.management.ManagementFactory;
import javax.annotation.concurrent.Immutable;
import javax.management.*;

/**
 * Decorates a given file system manager with a pace manager.
 *
 * @author Christian Schlichtherle
 */
@Immutable
public final class PaceManagerFactory extends FsManagerDecorator {

    /**
     * Constructs a new pace manager factory.
     * 
     * @deprecated This constructor is reserved for exclusive use by the
     *             {@link FsManagerLocator#SINGLETON}!
     *             Call {@link #newMXBeanProxy} instead to refer to the single
     *             pace manager which interfaces with JMX.
     *             
     */
    @Deprecated
    public PaceManagerFactory() { }

    /**
     * Returns a new MXBean proxy for the singleton pace manager which
     * interfaces with JMX.
     * Each proxy can get used immediately but will effectively refer to the
     * singleton pace manager only once it has been
     * {@linkplain #decorate installed}.
     * 
     * @return A new MXBean proxy for the singleton pace manager which
     *         interfaces with JMX.
     */
    public static PaceManager newMXBeanProxy() {
        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        return JMX.newMXBeanProxy(mbs, Lazy.getObjectName(), PaceManager.class);
    }

    /**
     * Decorates the given file system manager with a new pace manager.
     * Upon the first call only, the new pace manager gets installed as the
     * singleton pace manager which interfaces with JMX.
     * 
     * @param      manager the file system manager to decorate.
     * @return     the decorated file system manager.
     * @deprecated This method is reserved for exclusive use by the
     *             {@link FsManagerLocator#SINGLETON}!
     *             Call {@link #newMXBeanProxy} instead to refer to the single
     *             pace manager which interfaces with JMX.
     *             
     */
    @Deprecated
    @Override
    public FsManager decorate(FsManager manager) {
        return Lazy.view.decorate(manager);
    }

    private static final class Lazy {
        static final PaceManagerView
                view = new PaceManagerView(new PaceManagerModel());

        static {
            final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
            try {
                mbs.registerMBean(view, getObjectName());
            } catch (final MBeanRegistrationException ex) {
                throw new AssertionError(ex);
            } catch (final NotCompliantMBeanException ex) {
                throw new AssertionError(ex);
            } catch (InstanceAlreadyExistsException ex) {
                throw new AssertionError(ex);
            }
        }

        static ObjectName getObjectName() {
            try {
                return new ObjectName(  PaceManager.class.getPackage().getName(),
                                        "type", PaceManager.class.getSimpleName());
            } catch (MalformedObjectNameException ex) {
                throw new AssertionError(ex);
            }
        }
    } // Boot
}