package com.onaro.sanscreen.client.jmxframework.service;

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

import javax.swing.SwingUtilities;

import com.onaro.sanscreen.client.MainDirector;
import com.onaro.sanscreen.client.jmxframework.FrameworkService;

    /**
     * MBean Shutdown service class.   
     * Exposes functionality to shutdown the Client.  Mainly used by UT.
     * 
     * @author Rick Noel
     *
     */
@SuppressWarnings("nls")
public class ShutdownService extends FrameworkService implements ShutdownServiceMBean {

    /**
     * Name of service.  Used to look up service via JNDI
     */
    public static final String NAME = "Shutdown Service";
    
    // Using sun.awt.AppContext to work around Oracle bug in Java 7 only.   
    @SuppressWarnings("restriction")
    private static sun.awt.AppContext mainThreadContext = null;
    
    public ShutdownService() {
        super(NAME);
    }

    @SuppressWarnings("restriction")
    @Override
    public void doStart() {
        // Using sun.awt.AppContext to work around Oracle bug in Java 7 only.   
        if (mainThreadContext == null && System.getProperty("java.version").startsWith("1.7.")) {
            mainThreadContext = sun.awt.AppContext.getAppContext();
        }
    }

    @Override
    public void doStop() {
    }

    @Override
    public String getStatus() {
        return "Running";
    }

    /**
     * Main method of the service callable from JMX.  Shuts down the client.
     */
    @Override
    public void shutdown() {
        // Special shutdown required when running on Java 7 VM.
        if (mainThreadContext != null) {
            shutdown_java7();
        } else {
            MainDirector.getMainDirector().exit(false);
        }
    }
        
    /**
     * Shuts down client when client is running on a Java 7 VM.
     * <P>
     * There is a bug introduced by Oracle in Java 7u25 that causes a null pointer exception
     * when the test tries to close the application. The NPE occurs within the Sun AWT Toolkit.
     * See <a href="http://bugs.sun.com/view_bug.do?bug_id=8017776">Sun bug 8017776</a>.
     * Unfortunately, this will not be fixed until Java 8.
     * <P>
     * Below is a workaround based on info discovered from various sources.
     * Note we don't support Java 7 prior to update 25, so we use this workaround for all Java 7 VMs.
     */
    @SuppressWarnings({"unchecked", "restriction"})
    private void shutdown_java7() {
        try {
            // Change context to that used by MainDirector class (Swing thread).
            final Field field = sun.awt.AppContext.class.getDeclaredField ("threadGroup2appContext"); //$NON-NLS-1$
            field.setAccessible(true);
            Map<ThreadGroup, sun.awt.AppContext> threadGroup2appContext =
                (Map<ThreadGroup, sun.awt.AppContext>)field.get (null);
            final ThreadGroup currentThreadGroup = Thread.currentThread().getThreadGroup();
            threadGroup2appContext.put (currentThreadGroup, mainThreadContext);
                        
            SwingUtilities.invokeAndWait(new Runnable() {
                @Override
                public void run() {
                    try {
                        // Shutdown.
                        MainDirector.getMainDirector().exit(false);
                        
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}