/*******************************************************************************
 * Copyright (c) 2000, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.debug.core.breakpoints;

 
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.Preferences;
import org.eclipse.debug.core.DebugEvent;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.IDebugEventSetListener;
import org.eclipse.debug.core.model.Breakpoint;
import org.eclipse.debug.core.model.IDebugTarget;
import org.eclipse.jdt.debug.core.IJavaBreakpoint;
import org.eclipse.jdt.debug.core.IJavaDebugTarget;
import org.eclipse.jdt.debug.core.IJavaObject;
import org.eclipse.jdt.debug.core.IJavaThread;
import org.eclipse.jdt.debug.core.IJavaType;
import org.eclipse.jdt.debug.core.JDIDebugModel;
import org.eclipse.jdt.internal.debug.core.IJDIEventListener;
import org.eclipse.jdt.internal.debug.core.JDIDebugPlugin;
import org.eclipse.jdt.internal.debug.core.model.JDIDebugTarget;
import org.eclipse.jdt.internal.debug.core.model.JDIObjectValue;
import org.eclipse.jdt.internal.debug.core.model.JDIThread;
import org.eclipse.jdt.internal.debug.core.model.JDIType;

import com.ibm.icu.text.MessageFormat;
import com.sun.jdi.ObjectReference;
import com.sun.jdi.ReferenceType;
import com.sun.jdi.ThreadReference;
import com.sun.jdi.VMDisconnectedException;
import com.sun.jdi.event.ClassPrepareEvent;
import com.sun.jdi.event.Event;
import com.sun.jdi.event.LocatableEvent;
import com.sun.jdi.request.ClassPrepareRequest;
import com.sun.jdi.request.EventRequest;
import com.sun.jdi.request.EventRequestManager;

public abstract class JavaBreakpoint extends Breakpoint implements IJavaBreakpoint, IJDIEventListener, IDebugEventSetListener {

	/**
	 * Breakpoint attribute storing the expired value (value <code>"org.eclipse.jdt.debug.core.expired"</code>).
	 * This attribute is stored as a <code>boolean</code>. Once a hit count has
	 * been reached, a breakpoint is considered to be "expired".
	 */
	protected static final String EXPIRED = "org.eclipse.jdt.debug.core.expired"; //$NON-NLS-1$
	/**
	 * Breakpoint attribute storing a breakpoint's hit count value
	 * (value <code>"org.eclipse.jdt.debug.core.hitCount"</code>). This attribute is stored as an
	 * <code>int</code>.
	 */
	protected static final String HIT_COUNT = "org.eclipse.jdt.debug.core.hitCount"; //$NON-NLS-1$
	/**
	 * Breakpoint attribute storing the number of debug targets a
	 * breakpoint is installed in (value <code>"org.eclipse.jdt.debug.core.installCount"</code>).
	 * This attribute is a <code>int</code>.
	 */
	protected static final String INSTALL_COUNT = "org.eclipse.jdt.debug.core.installCount"; //$NON-NLS-1$	
	
	/**
	 * Breakpoint attribute storing the fully qualified name of the type
	 * this breakpoint is located in.
	 * (value <code>"org.eclipse.jdt.debug.core.typeName"</code>). This attribute is a <code>String</code>.
	 */
	protected static final String TYPE_NAME = "org.eclipse.jdt.debug.core.typeName"; //$NON-NLS-1$		
	
	/**
	 * Breakpoint attribute storing suspend policy code for 
	 * this breakpoint.
	 * (value <code>"org.eclipse.jdt.debug.core.suspendPolicy</code>).
	 * This attribute is an <code>int</code> corresponding
	 * to <code>IJavaBreakpoint.SUSPEND_VM</code> or
	 * <code>IJavaBreakpoint.SUSPEND_THREAD</code>.
	 */
	protected static final String SUSPEND_POLICY = "org.eclipse.jdt.debug.core.suspendPolicy"; //$NON-NLS-1$			
	
	/**
	 * Stores the collection of requests that this breakpoint has installed in
	 * debug targets.
	 * key: a debug target
	 * value: the requests this breakpoint has installed in that target
	 */
	protected HashMap fRequestsByTarget;
	
	/**
	 * The list of threads (ThreadReference objects) in which this breakpoint will suspend,
	 * associated with the target in which each thread exists (JDIDebugTarget).
	 * key: targets the debug targets (IJavaDebugTarget)
	 * value: thread the filtered thread (IJavaThread) in the given target
	 */
	protected Map fFilteredThreadsByTarget;
	
	/**
	 * Stores the type name that this breakpoint was last installed
	 * in. When a breakpoint is created, the TYPE_NAME attribute assigned to it
	 * is that of its top level enclosing type. When installed, the type
	 * may actually be an inner type. We need to keep track of the type 
	 * type the breakpoint was installed in, in case we need to re-install
	 * the breakpoint for HCR (i.e. in case an inner type is HCR'd).
	 */
	protected String fInstalledTypeName = null;
	
	/**
	 * List of targets in which this breakpoint is installed.
	 * Used to prevent firing of more than one install notification
	 * when a breakpoint's requests are re-created.
	 */
	protected Set fInstalledTargets = null;
	
	/**
	 * List of active instance filters for this breakpoint
	 * (list of <code>IJavaObject</code>).
	 */
	protected List fInstanceFilters = null;
	
	/**
	 * Empty instance filters array.
	 */
	protected static final IJavaObject[] fgEmptyInstanceFilters = new IJavaObject[0];
	
	/**
	 * Property identifier for a breakpoint object on an event request
	 */
	public static final String JAVA_BREAKPOINT_PROPERTY = "org.eclipse.jdt.debug.breakpoint"; //$NON-NLS-1$
	
	/**
	 * JavaBreakpoint attributes
	 */	
	protected static final String[] fgExpiredEnabledAttributes= new String[]{EXPIRED, ENABLED};
	
	public JavaBreakpoint() {
		fRequestsByTarget = new HashMap(1);
		fFilteredThreadsByTarget= new HashMap(1);
	}	

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.IBreakpoint#getModelIdentifier()
	 */
	public String getModelIdentifier() {
		return JDIDebugModel.getPluginIdentifier();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.Breakpoint#setMarker(org.eclipse.core.resources.IMarker)
	 */
	public void setMarker(IMarker marker) throws CoreException {
		super.setMarker(marker);
		configureAtStartup();
	}

	/**
	 * Add this breakpoint to the breakpoint manager,
	 * or sets it as unregistered.
	 */
	protected void register(boolean register) throws CoreException {
        DebugPlugin plugin = DebugPlugin.getDefault();
		if (plugin != null && register) {
            plugin.getBreakpointManager().addBreakpoint(this);
		} else {
			setRegistered(false);
		}
	}	
	
	/**
	 * Add the given event request to the given debug target. If 
	 * the request is the breakpoint request associated with this 
	 * breakpoint, increment the install count.
	 */
	protected void registerRequest(EventRequest request, JDIDebugTarget target) throws CoreException {
		if (request == null) {
			return;
		}
		List reqs = getRequests(target);
		if (reqs.isEmpty()) {
			fRequestsByTarget.put(target, reqs);
		}
		reqs.add(request);
		target.addJDIEventListener(this, request);
		// update the install attribute on the breakpoint
		if (!(request instanceof ClassPrepareRequest)) {
			incrementInstallCount();
			// notification 
			fireInstalled(target);
		}
	}
	
	/**
	 * Returns a String corresponding to the reference type
	 * name to the top enclosing type in which this breakpoint
	 * is located or <code>null</code> if no reference type could be
	 * found.
	 */
	protected String getEnclosingReferenceTypeName() throws CoreException {
		String name= getTypeName();
		int index = name.indexOf('$');
		if (index == -1) {
			return name;
		}
		return name.substring(0, index);
	}	
		
	/**
	 * Returns the requests that this breakpoint has installed
	 * in the given target.
	 */
	protected ArrayList getRequests(JDIDebugTarget target) {
		ArrayList list= (ArrayList)fRequestsByTarget.get(target);
		if (list == null) {
			list= new ArrayList(2);
		}
		return list;
	}
	
	/**
	 * Remove the given request from the given target. If the request
	 * is the breakpoint request associated with this breakpoint,
	 * decrement the install count.
	 */
	protected void deregisterRequest(EventRequest request, JDIDebugTarget target) throws CoreException {
		target.removeJDIEventListener(this, request);
		// A request may be getting de-registered because the breakpoint has
		// been deleted. It may be that this occurred because of a marker deletion.
		// Don't try updating the marker (decrementing the install count) if
		// it no longer exists.
		if (!(request instanceof ClassPrepareRequest) && getMarker().exists()) {
			decrementInstallCount();
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.internal.debug.core.IJDIEventListener#handleEvent(com.sun.jdi.event.Event, org.eclipse.jdt.internal.debug.core.model.JDIDebugTarget)
	 */
	public boolean handleEvent(Event event, JDIDebugTarget target) {
		if (event instanceof ClassPrepareEvent) {
			return handleClassPrepareEvent((ClassPrepareEvent)event, target);
		}
		ThreadReference threadRef= ((LocatableEvent)event).thread();
		JDIThread thread= target.findThread(threadRef);	
		if (thread == null || thread.isIgnoringBreakpoints()) {
			return true;
		}
		return handleBreakpointEvent(event, target, thread);		
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.internal.debug.core.IJDIEventListener#wonSuspendVote(com.sun.jdi.event.Event, org.eclipse.jdt.internal.debug.core.model.JDIDebugTarget)
	 */
	public void wonSuspendVote(Event event, JDIDebugTarget target) {
		ThreadReference threadRef = null;
		if (event instanceof ClassPrepareEvent) {
			threadRef = ((ClassPrepareEvent)event).thread();
		} else if (event instanceof LocatableEvent) {
			threadRef = ((LocatableEvent)event).thread();
		}
		if (threadRef == null) {
			return;
		}
		JDIThread thread= target.findThread(threadRef);	
		if (thread == null || thread.isIgnoringBreakpoints()) {
			return;
		}
		thread.wonSuspendVote(this);
	}

	/**
	 * Handle the given class prepare event, which was generated by the
	 * class prepare event installed in the given target by this breakpoint.
	 * 
	 * If the class which has been loaded is a class in which this breakpoint
	 * should install, create a breakpoint request for that class.
	 */	
	public boolean handleClassPrepareEvent(ClassPrepareEvent event, JDIDebugTarget target) {
		try {
			if (!installableReferenceType(event.referenceType(), target)) {
				// Don't install this breakpoint in an
				// inappropriate type
				return true;
			}			
			createRequest(target, event.referenceType());
		} catch (CoreException e) {
			JDIDebugPlugin.log(e);
		}
		return true;
	}
	
	/**
	 * @see IJDIEventListener#handleEvent(Event, JDIDebugTarget)
	 * 
	 * Handle the given event, which was generated by the breakpoint request
	 * installed in the given target by this breakpoint.
	 */
	public boolean handleBreakpointEvent(Event event, JDIDebugTarget target, JDIThread thread) {
		expireHitCount(event);
		return !suspend(thread); // Resume if suspend fails
	}
	
	/**
	 * Delegates to the given thread to suspend, and
	 * returns whether the thread suspended
	 * It is possible that the thread will not suspend
	 * as directed by a Java breakpoint listener.
	 * 
	 * @see IJavaBreakpointListener#breakpointHit(IJavaThread, IJavaBreakpoint)
	 */
	protected boolean suspend(JDIThread thread) {
		return thread.handleSuspendForBreakpoint(this, true);
	}
	
	/**
	 * Returns whether the given reference type is appropriate for this
	 * breakpoint to be installed in the given target. Query registered
	 * breakpoint listeners.
	 */
	protected boolean installableReferenceType(ReferenceType type, JDIDebugTarget target) throws CoreException {
		String installableType= getTypeName();
		String queriedType= type.name();
		if (installableType == null || queriedType == null) {
			return false;
		}
		int index= queriedType.indexOf('<');
		if (index != -1) {
			queriedType= queriedType.substring(0, index);
		}
		if (installableType.equals(queriedType)) {
			return queryInstallListeners(target, type);
		}
		index= queriedType.indexOf('$', 0);
		if (index == -1) {
			return false;
		}
		if (installableType.regionMatches(0, queriedType, 0, index)) {
			return queryInstallListeners(target, type);
		}
		return false;
	}
	
	/**
	 * Called when a breakpoint event is encountered. Expires the
	 * hit count in the event's request and updates the marker.
	 * @param event the event whose request should have its hit count
	 * expired or <code>null</code> to only update the breakpoint marker.
	 */
	protected void expireHitCount(Event event) {
		Integer requestCount= null;
		EventRequest request= null;
		if (event != null) {
			request= event.request();
			requestCount= (Integer) request.getProperty(HIT_COUNT);
		}
		if (requestCount != null) {
			if (request != null) {
				request.putProperty(EXPIRED, Boolean.TRUE);
			}
			try {
				setAttributes(fgExpiredEnabledAttributes, new Object[]{Boolean.TRUE, Boolean.FALSE});
				// make a note that we auto-disabled this breakpoint.
			} catch (CoreException ce) {
				JDIDebugPlugin.log(ce);
			}
		}
	}
	
	/**
	 * Returns whether this breakpoint should be "skipped". Breakpoints
	 * are skipped if the breakpoint manager is disabled and the breakpoint
	 * is registered with the manager
	 * 
	 * @return whether this breakpoint should be skipped
	 */
	public boolean shouldSkipBreakpoint() throws CoreException {
		DebugPlugin plugin = DebugPlugin.getDefault();
        return plugin != null && isRegistered() && !plugin.getBreakpointManager().isEnabled();
	}

	/**
	 * Attempts to create a breakpoint request for this breakpoint in the given
	 * reference type in the given target.
	 * 
	 * @return Whether a request was created
	 */
	protected boolean createRequest(JDIDebugTarget target, ReferenceType type) throws CoreException {
		if (shouldSkipBreakpoint()) {
			return false;
		}
		EventRequest[] requests= newRequests(target, type);
		if (requests == null) {
			return false;
		}
		fInstalledTypeName = type.name();
		for (int i = 0; i < requests.length; i++) {
            EventRequest request = requests[i];
            registerRequest(request, target);    
        }
		return true;
	}
	
	/**
	 * Configure a breakpoint request with common properties:
	 * <ul>
	 * <li><code>JAVA_BREAKPOINT_PROPERTY</code></li>
	 * <li><code>HIT_COUNT</code></li>
	 * <li><code>EXPIRED</code></li>
	 * </ul>
	 * and sets the suspend policy of the request to suspend 
	 * the event thread.
	 */
	protected void configureRequest(EventRequest request, JDIDebugTarget target) throws CoreException {
		request.setSuspendPolicy(getJDISuspendPolicy());
		request.putProperty(JAVA_BREAKPOINT_PROPERTY, this);
		configureRequestThreadFilter(request, target);
		configureRequestHitCount(request);
		configureInstanceFilters(request, target);
		// Important: only enable a request after it has been configured
		updateEnabledState(request, target);
	}
	
	/**
	 * Adds an instance filter to the given request. Since the implementation is
	 * request specific, subclasses must override.
	 * 
	 * @param request
	 * @param object instance filter
	 */
	protected abstract void addInstanceFilter(EventRequest request, ObjectReference object);
	
	/**
	 * Configure the thread filter property of the given request.
	 */
	protected void configureRequestThreadFilter(EventRequest request, JDIDebugTarget target) {
		IJavaThread thread= (IJavaThread)fFilteredThreadsByTarget.get(target);
		if (thread == null || (!(thread instanceof JDIThread))) {
			return;
		}
		setRequestThreadFilter(request, ((JDIThread)thread).getUnderlyingThread());
	}
	
	/**
	 * Configure the given request's hit count
	 */
	protected void configureRequestHitCount(EventRequest request) throws CoreException {
		int hitCount= getHitCount();
		if (hitCount > 0) {
			request.addCountFilter(hitCount);
			request.putProperty(HIT_COUNT, new Integer(hitCount));
		}
	}
	
	protected void configureInstanceFilters(EventRequest request, JDIDebugTarget target) {
		if (fInstanceFilters != null && !fInstanceFilters.isEmpty()) {
			Iterator iter = fInstanceFilters.iterator();
			while (iter.hasNext()) {
				IJavaObject object = (IJavaObject)iter.next();
				if (object.getDebugTarget().equals(target)) {
					addInstanceFilter(request, ((JDIObjectValue)object).getUnderlyingObject());
				}
			}
		}
	}	
	
	/**
	 * Creates, installs, and returns all event requests for this breakpoint
	 * in the given reference type and and target.
	 * 
	 * @return the event requests created or <code>null</code> if creation failed
	 */
	protected abstract EventRequest[] newRequests(JDIDebugTarget target, ReferenceType type) throws CoreException;
	
	/**
	 * Add this breakpoint to the given target. After it has been
	 * added to the given target, this breakpoint will suspend
	 * execution of that target as appropriate.
	 */
	public void addToTarget(JDIDebugTarget target) throws CoreException {
		fireAdding(target);
		createRequests(target);
	}
	
	/**
	 * Creates event requests for the given target
	 */
	protected void createRequests(JDIDebugTarget target) throws CoreException {
		if (target.isTerminated() || shouldSkipBreakpoint()) {
			return;
		}
		String referenceTypeName= getTypeName();
		String enclosingTypeName= getEnclosingReferenceTypeName();
		if (referenceTypeName == null || enclosingTypeName == null) {
			return;
		}
		// create request to listen to class loads
		if (referenceTypeName.indexOf('$') == -1) {
			registerRequest(target.createClassPrepareRequest(enclosingTypeName), target);
			//register to ensure we hear about local and anonymous inner classes
			registerRequest(target.createClassPrepareRequest(enclosingTypeName + "$*"), target);  //$NON-NLS-1$
		} else {
			registerRequest(target.createClassPrepareRequest(referenceTypeName), target);
			//register to ensure we hear about local and anonymous inner classes
			registerRequest(target.createClassPrepareRequest(enclosingTypeName + "$*", referenceTypeName), target);  //$NON-NLS-1$
		}

		// create breakpoint requests for each class currently loaded
		List classes= target.jdiClassesByName(referenceTypeName);
		if (classes.isEmpty() && enclosingTypeName.equals(referenceTypeName)) {
			return;
		}

		boolean success= false;
		Iterator iter = classes.iterator();
		while (iter.hasNext()) {
			ReferenceType type= (ReferenceType) iter.next();
			if (createRequest(target, type)) {
				success= true;
			}
		}

		if (!success) {
			addToTargetForLocalType(target, enclosingTypeName);
		}		
	}
	
	/**
	 * Local types (types defined in methods) are handled specially due to the
	 * different types that the local type is associated with as well as the 
	 * performance problems of using ReferenceType#nestedTypes.  From the Java 
	 * model perspective a local type is defined within a method of a type.  
	 * Therefore the type of a breakpoint placed in a local type is the type
	 * that encloses the method where the local type was defined.
	 * The local type is enclosed within the top level type according
	 * to the VM.
	 * So if "normal" attempts to create a request when a breakpoint is
	 * being added to a target fail, we must be dealing with a local type and therefore resort
	 * to looking up all of the nested types of the top level enclosing type.
	 */
	protected void addToTargetForLocalType(JDIDebugTarget target, String enclosingTypeName) throws CoreException {
		List classes= target.jdiClassesByName(enclosingTypeName);
		if (!classes.isEmpty()) {
			Iterator iter = classes.iterator();
			while (iter.hasNext()) {
				ReferenceType type= (ReferenceType) iter.next();
				Iterator nestedTypes= type.nestedTypes().iterator();
				while (nestedTypes.hasNext()) {
					ReferenceType nestedType= (ReferenceType) nestedTypes.next();
					if (createRequest(target, nestedType)) {
						break;
					}				
				}
			}
		}
	}
			
	/**
	 * Returns the JDI suspend policy that corresponds to this
	 * breakpoint's suspend policy
	 * 
	 * @return the JDI suspend policy that corresponds to this
	 *  breakpoint's suspend policy
	 * @exception CoreException if unable to access this breakpoint's
	 *  suspend policy setting
	 */
	protected int getJDISuspendPolicy() throws CoreException {
		int breakpointPolicy = getSuspendPolicy();
		if (breakpointPolicy == IJavaBreakpoint.SUSPEND_THREAD) {
			return EventRequest.SUSPEND_EVENT_THREAD;
		}
		return EventRequest.SUSPEND_ALL;
	}

	/**
	 * returns the default suspend policy based on the pref setting on the 
	 * Java-Debug pref page
	 * @return the default suspend policy
	 * @since 3.2
	 */
	protected int getDefaultSuspendPolicy() {
		Preferences store = JDIDebugModel.getPreferences();
		return store.getInt(JDIDebugPlugin.PREF_DEFAULT_BREAKPOINT_SUSPEND_POLICY);
	}
	
	
	/**
	 * Returns whether the hitCount of this breakpoint is equal to the hitCount of
	 * the associated request.
	 */
	protected boolean hasHitCountChanged(EventRequest request) throws CoreException {
		int hitCount= getHitCount();
		Integer requestCount= (Integer) request.getProperty(HIT_COUNT);
		int oldCount = -1;
		if (requestCount != null)  {
			oldCount = requestCount.intValue();
		} 
		return hitCount != oldCount;
	}
	
	/**
	 * Removes this breakpoint from the given target.
	 */
	public void removeFromTarget(final JDIDebugTarget target) throws CoreException {
		removeRequests(target);
		Object removed = fFilteredThreadsByTarget.remove(target);
		boolean changed = removed != null;
		boolean markerExists = markerExists();
		if (!markerExists || (markerExists && getInstallCount() == 0)) {
			fInstalledTypeName = null;
		}
		
		// remove instance filters 
		if (fInstanceFilters != null && !fInstanceFilters.isEmpty()) {
			for (int i = 0; i < fInstanceFilters.size(); i++) {
				IJavaObject object = (IJavaObject)fInstanceFilters.get(i);
				if (object.getDebugTarget().equals(target)) {
					fInstanceFilters.remove(i);
					changed = true;
				}
			}
		}
		
		// fire change notification if required
		if (changed) {
			fireChanged();
		}
		
		// notification
		fireRemoved(target);
	}		
	
	/**
	 * Remove all requests that this breakpoint has installed in the given
	 * debug target.
	 */
	protected void removeRequests(final JDIDebugTarget target) throws CoreException {
		// removing was previously done is a workspace runnable, but that is
		// not possible since it can be a resource callback (marker deletion) that
		// causes a breakpoint to be removed
		ArrayList requests= (ArrayList)getRequests(target).clone();
		// Iterate over a copy of the requests since this list of requests
		// can be changed in other threads which would cause an ConcurrentModificationException
		Iterator iter = requests.iterator();
		EventRequest req;
		while (iter.hasNext()) {
			req = (EventRequest)iter.next();
			try {
				if (target.isAvailable() && !isExpired(req)) { // cannot delete an expired request
					EventRequestManager manager = target.getEventRequestManager();
					if (manager != null) {
						manager.deleteEventRequest(req); // disable & remove 
					}					
				}
			} catch (VMDisconnectedException e) {
				if (target.isAvailable()) {
					JDIDebugPlugin.log(e);
				}
			} catch (RuntimeException e) {
                target.internalError(e);
			} finally {
				deregisterRequest(req, target);
			}
		}
		fRequestsByTarget.remove(target);
	}
		
	/**
	 * Update the enabled state of the given request in the given target, which is associated
	 * with this breakpoint. Set the enabled state of the request
	 * to the enabled state of this breakpoint.
	 */
	protected void updateEnabledState(EventRequest request, JDIDebugTarget target) throws CoreException  {
		internalUpdateEnabledState(request, isEnabled(), target);
	}
	
	/**
	 * Set the enabled state of the given request to the given
	 * value, also taking into account instance filters.
	 */
	protected void internalUpdateEnabledState(EventRequest request, boolean enabled, JDIDebugTarget target) {
		if (request.isEnabled() != enabled) {
			// change the enabled state
			try {
				// if the request has expired, do not disable.
				// BreakpointRequests that have expired cannot be deleted.
				if (!isExpired(request)) {
					request.setEnabled(enabled);
				}
			} catch (VMDisconnectedException e) {
			} catch (RuntimeException e) {
				target.internalError(e);
			}
		}
	}
		
	/**
	 * Returns whether this breakpoint has expired.
	 */
	public boolean isExpired() throws CoreException {
		return ensureMarker().getAttribute(EXPIRED, false);
	}	
	
	/**
	 * Returns whether the given request is expired
	 */
	protected boolean isExpired(EventRequest request) {
		Boolean requestExpired= (Boolean) request.getProperty(EXPIRED);
		if (requestExpired == null) {
				return false;
		}
		return requestExpired.booleanValue();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#isInstalled()
	 */
	public boolean isInstalled() throws CoreException {
		return ensureMarker().getAttribute(INSTALL_COUNT, 0) > 0;
	}	
	
	/**
	 * Increments the install count of this breakpoint
	 */
	protected void incrementInstallCount() throws CoreException {	
		int count = getInstallCount();
		setAttribute(INSTALL_COUNT, count + 1);
	}	
	
	/**
	 * Returns the <code>INSTALL_COUNT</code> attribute of this breakpoint
	 * or 0 if the attribute is not set.
	 */
	public int getInstallCount() throws CoreException {
		return ensureMarker().getAttribute(INSTALL_COUNT, 0);
	}	

	/**
	 * Decrements the install count of this breakpoint.
	 */
	protected void decrementInstallCount() throws CoreException {
		int count= getInstallCount();
		if (count > 0) {
			setAttribute(INSTALL_COUNT, count - 1);	
		}
		if (count == 1) {
			if (isExpired()) {
				// if breakpoint was auto-disabled, re-enable it
				setAttributes(fgExpiredEnabledAttributes,
						new Object[]{Boolean.FALSE, Boolean.TRUE});
			}
		}
	}
	
	/**
	 * Sets the type name in which to install this breakpoint.
	 */
	protected void setTypeName(String typeName) throws CoreException {
		setAttribute(TYPE_NAME, typeName);
	}	

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getTypeName()
	 */
	public String getTypeName() throws CoreException {
		if (fInstalledTypeName == null) {
			return ensureMarker().getAttribute(TYPE_NAME, null);
		}
		return fInstalledTypeName;
	}
	
	/**
	 * Resets the install count attribute on this breakpoint's marker
	 * to "0".  Resets the expired attribute on all breakpoint markers to <code>false</code>.
	 * Resets the enabled attribute on the breakpoint marker to <code>true</code>.
	 * If a workbench crashes, the attributes could have been persisted
	 * in an incorrect state.
	 */
	private void configureAtStartup() throws CoreException {
		List attributes= null;
		List values= null;
		if (isInstalled()) {
			attributes= new ArrayList(3);
			values= new ArrayList(3);
			attributes.add(INSTALL_COUNT);
			values.add(new Integer(0));
		}
		if (isExpired()) {
			if (attributes == null) {
				attributes= new ArrayList(3);
				values= new ArrayList(3);
			}
			// if breakpoint was auto-disabled, re-enable it
			attributes.add(EXPIRED);
			values.add(Boolean.FALSE);
			attributes.add(ENABLED);
			values.add(Boolean.TRUE);
		}
		if (attributes != null) {
			String[] strAttributes= new String[attributes.size()];
			setAttributes((String[])attributes.toArray(strAttributes), values.toArray());
		}
	}	

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getHitCount()
	 */
	public int getHitCount() throws CoreException {
		return ensureMarker().getAttribute(HIT_COUNT, -1);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#setHitCount(int)
	 */
	public void setHitCount(int count) throws CoreException {	
		if (getHitCount() != count) {
			if (!isEnabled() && count > -1) {
				setAttributes(new String []{ENABLED, HIT_COUNT, EXPIRED},
					new Object[]{Boolean.TRUE, new Integer(count), Boolean.FALSE});
			} else {
				setAttributes(new String[]{HIT_COUNT, EXPIRED},
					new Object[]{new Integer(count), Boolean.FALSE});
			}
			recreate();
		}
	}
	
	protected String getMarkerMessage(int hitCount, int suspendPolicy) {
		StringBuffer buff= new StringBuffer();
		if (hitCount > 0){
			buff.append(MessageFormat.format(JDIDebugBreakpointMessages.JavaBreakpoint___Hit_Count___0___1, new Object[]{Integer.toString(hitCount)})); 
			buff.append(' ');
		}
		String suspendPolicyString;
		if (suspendPolicy == IJavaBreakpoint.SUSPEND_THREAD) {
			suspendPolicyString= JDIDebugBreakpointMessages.JavaBreakpoint__suspend_policy__thread__1; 
		} else {
			suspendPolicyString= JDIDebugBreakpointMessages.JavaBreakpoint__suspend_policy__VM__2; 
		}
		
		buff.append(suspendPolicyString);
		return buff.toString();
	}	
	
	/**
	 * Sets whether this breakpoint's hit count has expired.
	 */
	public void setExpired(boolean expired) throws CoreException {
		setAttribute(EXPIRED, expired);	
	}	

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getSuspendPolicy()
	 */
	public int getSuspendPolicy() throws CoreException {
		return ensureMarker().getAttribute(SUSPEND_POLICY, IJavaBreakpoint.SUSPEND_THREAD);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#setSuspendPolicy(int)
	 */
	public void setSuspendPolicy(int suspendPolicy) throws CoreException {
		if(getSuspendPolicy() != suspendPolicy) {
			setAttribute(SUSPEND_POLICY, suspendPolicy);
			recreate();
		}
	}
	
	/**
	 * Notifies listeners this breakpoint is to be added to the
	 * given target.
	 * 
	 * @param target debug target
	 */
	protected void fireAdding(IJavaDebugTarget target) {
		JDIDebugPlugin plugin = JDIDebugPlugin.getDefault();
        if (plugin != null)
            plugin.fireBreakpointAdding(target, this);
	}
	
	/**
	 * Notifies listeners this breakpoint has been removed from the
	 * given target.
	 * 
	 * @param target debug target
	 */
	protected void fireRemoved(IJavaDebugTarget target) {
		JDIDebugPlugin plugin = JDIDebugPlugin.getDefault();
        if (plugin != null) {
            plugin.fireBreakpointRemoved(target, this);
            setInstalledIn(target, false);
        }
	}	
	
	/**
	 * Notifies listeners this breakpoint has been installed in the
	 * given target.
	 * 
	 * @param target debug target
	 */
	protected void fireInstalled(IJavaDebugTarget target) {
        JDIDebugPlugin plugin = JDIDebugPlugin.getDefault();
		if (plugin!= null && !isInstalledIn(target)) {
            plugin.fireBreakpointInstalled(target, this);
			setInstalledIn(target, true);
		}
	}	
	
	/**
	 * Returns whether this breakpoint is installed in the given target.
	 * 
	 * @param target
	 * @return whether this breakpoint is installed in the given target
	 */
	protected boolean isInstalledIn(IJavaDebugTarget target) {
		return fInstalledTargets != null && fInstalledTargets.contains(target);
	}
	
	/**
	 * Sets this breakpoint as installed in the given target
	 * 
	 * @param target
	 * @param installed whether installed
	 */
	protected void setInstalledIn(IJavaDebugTarget target, boolean installed) {
		if (installed) {
			if (fInstalledTargets == null) {
				fInstalledTargets = new HashSet();
			}
			fInstalledTargets.add(target);
		} else {
			if (fInstalledTargets != null) {
				fInstalledTargets.remove(target);
			}
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#setThreadFilter(org.eclipse.jdt.debug.core.IJavaThread)
	 */
	public void setThreadFilter(IJavaThread thread) throws CoreException {
		if (!(thread.getDebugTarget() instanceof JDIDebugTarget) || !(thread instanceof JDIThread)) {
			return;
		}
		JDIDebugTarget target= (JDIDebugTarget)thread.getDebugTarget();
		if (thread != fFilteredThreadsByTarget.put(target, thread) ) {
			// recreate the breakpoint only if it is not the same thread
			
			// Other breakpoints set attributes on the underlying
			// marker and the marker changes are eventually
			// propagated to the target. The target then asks the
			// breakpoint to update its request. Since thread filters
			// are transient properties, they are not set on
			// the marker. Thus we must update the request
			// here.
			recreate(target);
			fireChanged();
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.IDebugEventSetListener#handleDebugEvents(org.eclipse.debug.core.DebugEvent[])
	 */
	public void handleDebugEvents(DebugEvent[] events) {
		for (int i = 0; i < events.length; i++) {
			DebugEvent event = events[i];
			if (event.getKind() == DebugEvent.TERMINATE) {
				Object source= event.getSource();
				if (!(source instanceof JDIThread)) {
					return;
				}
				try {
					cleanupForThreadTermination((JDIThread)source);
				} catch (VMDisconnectedException exception) {
					// Thread death often occurs at shutdown.
					// A VMDisconnectedException trying to 
					// update the breakpoint request is
					// acceptable.
				}
			}
		}
	}
	
	/**
	 * Removes cached information relevant to this thread which has
	 * terminated.
	 * 
	 * Remove thread filters for terminated threads
	 * 
	 * Subclasses may override but need to call super.
	 */
	protected void cleanupForThreadTermination(JDIThread thread) {
		JDIDebugTarget target= (JDIDebugTarget)thread.getDebugTarget();
		try {
			if (thread == getThreadFilter(target)) {
				removeThreadFilter(target);
			}
		} catch (CoreException exception) {
			JDIDebugPlugin.log(exception);
		}
	}
	
	/** 
	 * EventRequest does not support thread filters, so they
	 * can't be set generically here. However, each of the breakpoint
	 * subclasses of EventRequest do support thread filters. So
	 * subclasses can set thread filters on their specific
	 * request type.
	 */
	protected abstract void setRequestThreadFilter(EventRequest request, ThreadReference thread);
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getThreadFilter(org.eclipse.jdt.debug.core.IJavaDebugTarget)
	 */
	public IJavaThread getThreadFilter(IJavaDebugTarget target) {
		return (IJavaThread)fFilteredThreadsByTarget.get(target);
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getThreadFilters()
	 */
	public IJavaThread[] getThreadFilters() {
		IJavaThread[] threads= null;
		Collection values= fFilteredThreadsByTarget.values();
		threads= new IJavaThread[values.size()];
		values.toArray(threads);
		return threads;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#removeThreadFilter(org.eclipse.jdt.debug.core.IJavaDebugTarget)
	 */
	public void removeThreadFilter(IJavaDebugTarget javaTarget) throws CoreException {
		if (!(javaTarget instanceof JDIDebugTarget)) {
			return;
		}
		JDIDebugTarget target= (JDIDebugTarget)javaTarget;
		if (fFilteredThreadsByTarget.remove(target) != null) {
			recreate(target);
			fireChanged();
		}
	}
	
	/**
	 * Returns whether this breakpoint should be installed in the given reference
	 * type in the given target according to registered breakpoint listeners.
	 * 
	 * @param target debug target
	 * @param type reference type or <code>null</code> if this breakpoint is
	 *  not installed in a specific type
	 */
	protected boolean queryInstallListeners(JDIDebugTarget target, ReferenceType type) {
        JDIDebugPlugin plugin = JDIDebugPlugin.getDefault();
        if (plugin != null) {
            IJavaType jt = null;
            if (type != null) {
                jt = JDIType.createType(target, type);
            }
            return plugin.fireInstalling(target, this, jt);
        }
        return false;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#addInstanceFilter(org.eclipse.jdt.debug.core.IJavaObject)
	 */
	public void addInstanceFilter(IJavaObject object) throws CoreException {
		if (fInstanceFilters == null) {
			fInstanceFilters= new ArrayList();
		}
		if (!fInstanceFilters.contains(object)) {
			fInstanceFilters.add(object);
			recreate((JDIDebugTarget)object.getDebugTarget());
			fireChanged();
		}
	}
	
	/**
	 * Change notification when there are no marker changes. If the marker
	 * does not exist, do not fire a change notification (the marker may not
	 * exist if the associated project was closed).
	 */
	protected void fireChanged() {
        DebugPlugin plugin = DebugPlugin.getDefault();
		if (plugin != null && markerExists()) {	
            plugin.getBreakpointManager().fireBreakpointChanged(this);
		}					
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#getInstanceFilters()
	 */
	public IJavaObject[] getInstanceFilters() {
		if (fInstanceFilters == null || fInstanceFilters.isEmpty()) {
			return fgEmptyInstanceFilters;
		}
		return (IJavaObject[])fInstanceFilters.toArray(new IJavaObject[fInstanceFilters.size()]);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#removeInstanceFilter(org.eclipse.jdt.debug.core.IJavaObject)
	 */
	public void removeInstanceFilter(IJavaObject object) throws CoreException {
		if (fInstanceFilters == null) {
			return;
		}
		if (fInstanceFilters.remove(object)) {
			recreate((JDIDebugTarget)object.getDebugTarget());
			fireChanged();
		}
	}
	
	/**
	 * An attribute of this breakpoint has changed - recreate event requests in
	 * all targets.
	 */
	protected void recreate() throws CoreException {
		DebugPlugin plugin = DebugPlugin.getDefault();
        if (plugin != null) {
            IDebugTarget[] targets = plugin.getLaunchManager().getDebugTargets();
            for (int i = 0; i < targets.length; i++) {
                IDebugTarget target = targets[i];
                MultiStatus multiStatus = new MultiStatus(JDIDebugPlugin.getUniqueIdentifier(), JDIDebugPlugin.ERROR, JDIDebugBreakpointMessages.JavaBreakpoint_Exception, null);
                IJavaDebugTarget jdiTarget = (IJavaDebugTarget) target.getAdapter(IJavaDebugTarget.class);
                if (jdiTarget instanceof JDIDebugTarget) {
                    try {
                        recreate((JDIDebugTarget) jdiTarget);
                    } catch (CoreException e) {
                        multiStatus.add(e.getStatus());
                    }
                }
                if (!multiStatus.isOK()) {
                    throw new CoreException(multiStatus);
                }
            }
        }
    }
	
	/**
	 * Recreate this breakpoint in the given target, as long as the
	 * target already contains this breakpoint.
	 * 
	 * @param target the target in which to re-create the breakpoint 
	 */
	protected void recreate(JDIDebugTarget target) throws CoreException {
		if (target.isAvailable() && target.getBreakpoints().contains(this)) {
			removeRequests(target);
			createRequests(target);
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.Breakpoint#setEnabled(boolean)
	 */
	public void setEnabled(boolean enabled) throws CoreException {
		super.setEnabled(enabled);
		recreate();
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#supportsInstanceFilters()
	 */
	public boolean supportsInstanceFilters() {
		return true;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.jdt.debug.core.IJavaBreakpoint#supportsThreadFilters()
	 */
	public boolean supportsThreadFilters() {
		return true;
	}
}