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/* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved.
*
* This program and the accompanying materials are made available under
* the terms of the Common Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/cpl-v10.html
*
* $Id: ExitHookManager.java,v 1.1.1.1 2004/05/09 16:57:58 vlad_r Exp $
*/
package com.vladium.util.exit;
import java.util.HashMap;
import java.util.Map;
import sun.misc.Signal;
import sun.misc.SignalHandler;
import com.vladium.util.IJREVersion;
import com.vladium.util.Property;
import com.vladium.emma.IAppConstants;
// ----------------------------------------------------------------------------
/**
* @author Vlad Roubtsov, (C) 2003
*/
public
abstract class ExitHookManager implements IJREVersion
{
// public: ................................................................
// TOTO: handle thread groups as well?
public abstract boolean addExitHook (Runnable runnable);
public abstract boolean removeExitHook (Runnable runnable);
public static synchronized ExitHookManager getSingleton ()
{
if (s_singleton == null)
{
if (JRE_1_3_PLUS)
{
s_singleton = new JRE13ExitHookManager ();
}
else if (JRE_SUN_SIGNAL_COMPATIBLE)
{
s_singleton = new SunJREExitHookManager ();
}
else
{
throw new UnsupportedOperationException ("no shutdown hook manager available [JVM: " + Property.getSystemFingerprint () + "]");
}
}
return s_singleton;
}
// protected: .............................................................
protected ExitHookManager () {}
// package: ...............................................................
// private: ...............................................................
private static final class JRE13ExitHookManager extends ExitHookManager
{
public synchronized boolean addExitHook (final Runnable runnable)
{
if ((runnable != null) && ! m_exitThreadMap.containsKey (runnable))
{
final Thread exitThread = new Thread (runnable, IAppConstants.APP_NAME + " shutdown handler thread");
try
{
Runtime.getRuntime ().addShutdownHook (exitThread);
m_exitThreadMap.put (runnable, exitThread); // TODO: use identity here
return true;
}
catch (Exception e)
{
System.out.println ("exception caught while adding a shutdown hook:");
e.printStackTrace (System.out);
}
}
return false;
}
public synchronized boolean removeExitHook (final Runnable runnable)
{
if (runnable != null)
{
final Thread exitThread = (Thread) m_exitThreadMap.get (runnable); // TODO: use identity here
if (exitThread != null)
{
try
{
Runtime.getRuntime ().removeShutdownHook (exitThread);
m_exitThreadMap.remove (runnable);
return true;
}
catch (Exception e)
{
System.out.println ("exception caught while removing a shutdown hook:");
e.printStackTrace (System.out);
}
}
}
return false;
}
JRE13ExitHookManager ()
{
m_exitThreadMap = new HashMap ();
}
private final Map /* Runnable->Thread */ m_exitThreadMap;
} // end of nested class
private static final class SunJREExitHookManager extends ExitHookManager
{
public synchronized boolean addExitHook (final Runnable runnable)
{
if ((runnable != null) && ! m_signalHandlerMap.containsKey (runnable))
{
final INTSignalHandler handler = new INTSignalHandler (runnable);
try
{
handler.register ();
m_signalHandlerMap.put (runnable, handler); // TODO: use identity here
return true;
}
catch (Throwable t)
{
System.out.println ("exception caught while adding a shutdown hook:");
t.printStackTrace (System.out);
}
}
return false;
}
public synchronized boolean removeExitHook (final Runnable runnable)
{
if (runnable != null)
{
final INTSignalHandler handler = (INTSignalHandler) m_signalHandlerMap.get (runnable); // TODO: use identity here
if (handler != null)
{
try
{
handler.unregister ();
m_signalHandlerMap.remove (runnable);
return true;
}
catch (Exception e)
{
System.out.println ("exception caught while removing a shutdown hook:");
e.printStackTrace (System.out);
}
}
}
return false;
}
SunJREExitHookManager ()
{
m_signalHandlerMap = new HashMap ();
}
private final Map /* Runnable->INTSignalHandler */ m_signalHandlerMap;
} // end of nested class
private static final class INTSignalHandler implements SignalHandler
{
public synchronized void handle (final Signal signal)
{
if (m_runnable != null)
{
try
{
m_runnable.run ();
}
catch (Throwable ignore) {}
}
m_runnable = null;
if ((m_previous != null) && (m_previous != SIG_DFL) && (m_previous != SIG_IGN))
{
try
{
// this does not work:
//Signal.handle (signal, m_previous);
//Signal.raise (signal);
m_previous.handle (signal);
}
catch (Throwable ignore) {}
}
else
{
System.exit (0);
}
}
INTSignalHandler (final Runnable runnable)
{
m_runnable = runnable;
}
synchronized void register ()
{
m_previous = Signal.handle (new Signal ("INT"), this);
}
synchronized void unregister ()
{
// if (m_previous != null)
// {
// Signal.handle (new Signal ("INT"), m_previous);
// m_previous = null;
// }
m_runnable = null;
}
private Runnable m_runnable;
private SignalHandler m_previous;
} // end of nested class
private static ExitHookManager s_singleton;
} // end of class
// ----------------------------------------------------------------------------
|
