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	/*
	* Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* This source code is provided to illustrate the usage of a given feature
	* or technique and has been deliberately simplified. Additional steps
	* required for a production-quality application, such as security checks,
	* input validation and proper error handling, might not be present in
	* this sample code.
	*/


	package com.sun.tools.example.debug.tty;

	import com.sun.jdi.*;
	import com.sun.jdi.event.*;
	import com.sun.jdi.request.EventRequest;

	public class EventHandler implements Runnable {

	EventNotifier notifier;
	Thread thread;
	volatile boolean connected = true;
	boolean completed = false;
	String shutdownMessageKey;
	boolean stopOnVMStart;

	EventHandler(EventNotifier notifier, boolean stopOnVMStart) {
	this.notifier = notifier;
	this.stopOnVMStart = stopOnVMStart;
	this.thread = new Thread(this, "event-handler");
	this.thread.start();
	}

	synchronized void shutdown() {
	connected = false; // force run() loop termination
	thread.interrupt();
	while (!completed) {
	try {wait();} catch (InterruptedException exc) {}
	}
	}

	@Override
	public void run() {
	EventQueue queue = Env.vm().eventQueue();
	while (connected) {
	try {
	EventSet eventSet = queue.remove();
	boolean resumeStoppedApp = false;
	EventIterator it = eventSet.eventIterator();
	while (it.hasNext()) {
	resumeStoppedApp \|= !handleEvent(it.nextEvent());
	}

	if (resumeStoppedApp) {
	eventSet.resume();
	} else if (eventSet.suspendPolicy() == EventRequest.SUSPEND_ALL) {
	setCurrentThread(eventSet);
	notifier.vmInterrupted();
	}
	} catch (InterruptedException exc) {
	// Do nothing. Any changes will be seen at top of loop.
	} catch (VMDisconnectedException discExc) {
	handleDisconnectedException();
	break;
	}
	}
	synchronized (this) {
	completed = true;
	notifyAll();
	}
	}

	private boolean handleEvent(Event event) {
	notifier.receivedEvent(event);

	if (event instanceof ExceptionEvent) {
	return exceptionEvent(event);
	} else if (event instanceof BreakpointEvent) {
	return breakpointEvent(event);
	} else if (event instanceof WatchpointEvent) {
	return fieldWatchEvent(event);
	} else if (event instanceof StepEvent) {
	return stepEvent(event);
	} else if (event instanceof MethodEntryEvent) {
	return methodEntryEvent(event);
	} else if (event instanceof MethodExitEvent) {
	return methodExitEvent(event);
	} else if (event instanceof ClassPrepareEvent) {
	return classPrepareEvent(event);
	} else if (event instanceof ClassUnloadEvent) {
	return classUnloadEvent(event);
	} else if (event instanceof ThreadStartEvent) {
	return threadStartEvent(event);
	} else if (event instanceof ThreadDeathEvent) {
	return threadDeathEvent(event);
	} else if (event instanceof VMStartEvent) {
	return vmStartEvent(event);
	} else {
	return handleExitEvent(event);
	}
	}

	private boolean vmDied = false;
	private boolean handleExitEvent(Event event) {
	if (event instanceof VMDeathEvent) {
	vmDied = true;
	return vmDeathEvent(event);
	} else if (event instanceof VMDisconnectEvent) {
	connected = false;
	if (!vmDied) {
	vmDisconnectEvent(event);
	}
	/*
	* Inform jdb command line processor that jdb is being shutdown. JDK-8154144.
	*/
	((TTY)notifier).setShuttingDown(true);
	Env.shutdown(shutdownMessageKey);
	return false;
	} else {
	throw new InternalError(MessageOutput.format("Unexpected event type",
	new Object[] {event.getClass()}));
	}
	}

	synchronized void handleDisconnectedException() {
	/*
	* A VMDisconnectedException has happened while dealing with
	* another event. We need to flush the event queue, dealing only
	* with exit events (VMDeath, VMDisconnect) so that we terminate
	* correctly.
	*/
	EventQueue queue = Env.vm().eventQueue();
	while (connected) {
	try {
	EventSet eventSet = queue.remove();
	EventIterator iter = eventSet.eventIterator();
	while (iter.hasNext()) {
	handleExitEvent(iter.next());
	}
	} catch (InterruptedException exc) {
	// ignore
	} catch (InternalError exc) {
	// ignore
	}
	}
	}

	private ThreadReference eventThread(Event event) {
	if (event instanceof ClassPrepareEvent) {
	return ((ClassPrepareEvent)event).thread();
	} else if (event instanceof LocatableEvent) {
	return ((LocatableEvent)event).thread();
	} else if (event instanceof ThreadStartEvent) {
	return ((ThreadStartEvent)event).thread();
	} else if (event instanceof ThreadDeathEvent) {
	return ((ThreadDeathEvent)event).thread();
	} else if (event instanceof VMStartEvent) {
	return ((VMStartEvent)event).thread();
	} else {
	return null;
	}
	}

	private void setCurrentThread(EventSet set) {
	ThreadReference thread;
	if (set.size() > 0) {
	/*
	* If any event in the set has a thread associated with it,
	* they all will, so just grab the first one.
	*/
	Event event = set.iterator().next(); // Is there a better way?
	thread = eventThread(event);
	} else {
	thread = null;
	}
	setCurrentThread(thread);
	}

	private void setCurrentThread(ThreadReference thread) {
	ThreadInfo.invalidateAll();
	ThreadInfo.setCurrentThread(thread);
	}

	private boolean vmStartEvent(Event event) {
	VMStartEvent se = (VMStartEvent)event;
	notifier.vmStartEvent(se);
	return stopOnVMStart;
	}

	private boolean breakpointEvent(Event event) {
	BreakpointEvent be = (BreakpointEvent)event;
	notifier.breakpointEvent(be);
	return true;
	}

	private boolean methodEntryEvent(Event event) {
	MethodEntryEvent me = (MethodEntryEvent)event;
	notifier.methodEntryEvent(me);
	return true;
	}

	private boolean methodExitEvent(Event event) {
	MethodExitEvent me = (MethodExitEvent)event;
	return notifier.methodExitEvent(me);
	}

	private boolean fieldWatchEvent(Event event) {
	WatchpointEvent fwe = (WatchpointEvent)event;
	notifier.fieldWatchEvent(fwe);
	return true;
	}

	private boolean stepEvent(Event event) {
	StepEvent se = (StepEvent)event;
	notifier.stepEvent(se);
	return true;
	}

	private boolean classPrepareEvent(Event event) {
	ClassPrepareEvent cle = (ClassPrepareEvent)event;
	notifier.classPrepareEvent(cle);

	if (!Env.specList.resolve(cle)) {
	MessageOutput.lnprint("Stopping due to deferred breakpoint errors.");
	return true;
	} else {
	return false;
	}
	}

	private boolean classUnloadEvent(Event event) {
	ClassUnloadEvent cue = (ClassUnloadEvent)event;
	notifier.classUnloadEvent(cue);
	return false;
	}

	private boolean exceptionEvent(Event event) {
	ExceptionEvent ee = (ExceptionEvent)event;
	notifier.exceptionEvent(ee);
	return true;
	}

	private boolean threadDeathEvent(Event event) {
	ThreadDeathEvent tee = (ThreadDeathEvent)event;
	ThreadInfo.removeThread(tee.thread());
	return false;
	}

	private boolean threadStartEvent(Event event) {
	ThreadStartEvent tse = (ThreadStartEvent)event;
	ThreadInfo.addThread(tse.thread());
	notifier.threadStartEvent(tse);
	return false;
	}

	public boolean vmDeathEvent(Event event) {
	shutdownMessageKey = "The application exited";
	notifier.vmDeathEvent((VMDeathEvent)event);
	return false;
	}

	public boolean vmDisconnectEvent(Event event) {
	shutdownMessageKey = "The application has been disconnected";
	notifier.vmDisconnectEvent((VMDisconnectEvent)event);
	return false;
	}
	}

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