org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/views/memory/ViewPaneRenderingMgr.java - gerrit/platform/eclipse.platform.debug - Git at Google

 /*******************************************************************************
  * Copyright (c) 2004, 2006 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.debug.internal.ui.views.memory;

 import java.io.IOException;
 import java.util.ArrayList;

 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.transform.TransformerException;

 import org.eclipse.core.runtime.CoreException;
 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.IDebugTarget;
 import org.eclipse.debug.core.model.IMemoryBlock;
 import org.eclipse.debug.internal.core.LaunchManager;
 import org.eclipse.debug.internal.ui.DebugUIPlugin;
 import org.eclipse.debug.ui.DebugUITools;
 import org.eclipse.debug.ui.memory.IMemoryRendering;
 import org.eclipse.debug.ui.memory.IMemoryRenderingContainer;
 import org.eclipse.debug.ui.memory.IMemoryRenderingSite;
 import org.eclipse.debug.ui.memory.IMemoryRenderingType;
 import org.eclipse.ui.IViewSite;
 import org.eclipse.ui.IWorkbenchPartSite;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;

 /**
  * A View Pane Rendering Manager manages all the rendering from a view pane.
  * It is responsible for handling debug events and removing renderings
  * from the view pane as a debug session is terminated.
  * In addition, the rendering manager is responsible for persisting memory renderings.
  * Renderings need to be persisted when the memory view is disposed.  If the view is
  * opened again, the same set of renderings will be created in the view pane if
  * the renderings are still valid.
  * @since 3.1
  */
 public class ViewPaneRenderingMgr implements IDebugEventSetListener{

 	private ArrayList fRenderings = new ArrayList();
 	private IMemoryRenderingContainer fViewPane;

 	private static final String RENDERINGS_TAG = "persistedMemoryRenderings"; //$NON-NLS-1$
 	private static final String MEMORY_RENDERING_TAG = "memoryRendering"; //$NON-NLS-1$
 	private static final String MEMORY_BLOCK = "memoryBlock"; //$NON-NLS-1$
 	private static final String RENDERING_ID = "renderingId"; //$NON-NLS-1$

 	public ViewPaneRenderingMgr(IMemoryRenderingContainer viewPane)
 	{
 		fViewPane = viewPane;
 		loadPersistedRenderings(getPrefId());
 	}

 	public void removeMemoryBlockRendering(IMemoryBlock mem, String renderingId)
 	{
 		if(fRenderings == null)
 			return;

 		IMemoryRendering[] toRemove = getRenderings(mem, renderingId);

 		for (int i=0; i<toRemove.length; i++)
 		{
 			fRenderings.remove(toRemove[i]);

 			// remove listener after the last memory block has been removed
 			if (fRenderings.size() == 0)
 			{
 				DebugPlugin.getDefault().removeDebugEventListener(this);
 			}
 		}

 		storeRenderings();
 	}


 	public void addMemoryBlockRendering(IMemoryRendering rendering) {

 		// do not allow duplicated objects
 		if (fRenderings.contains(rendering))
 			return;

 		fRenderings.add(rendering);

 		// add listener for the first memory block added
 		if (fRenderings.size() == 1)
 		{
 			DebugPlugin.getDefault().addDebugEventListener(this);
 		}

 		storeRenderings();
 	}


 	public void removeMemoryBlockRendering(IMemoryRendering rendering) {
 		if(rendering == null)
 			return;

 		if(!fRenderings.contains(rendering))
 			return;

 		fRenderings.remove(rendering);

 		// remove listener after the last memory block has been removed
 		if (fRenderings.size() == 0)
 		{
 			DebugPlugin.getDefault().removeDebugEventListener(this);
 		}

 		storeRenderings();
 	}

 	public IMemoryRendering[] getRenderings(IMemoryBlock mem, String renderingId)
 	{
 		if (renderingId == null)
 		{
 			return getRenderingsFromMemoryBlock(mem);
 		}

 		ArrayList ret = new ArrayList();
 		for (int i=0; i<fRenderings.size(); i++)
 		{
 			if (fRenderings.get(i) instanceof IMemoryRendering)
 			{
 				IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
 				if (rendering.getMemoryBlock() == mem && renderingId.equals(rendering.getRenderingId()))
 				{
 					ret.add(rendering);
 				}
 			}
 		}

 		return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
 	}

 	public IMemoryRendering[] getRenderings()
 	{
 		return (IMemoryRendering[])fRenderings.toArray(new IMemoryRendering[fRenderings.size()]);
 	}

 	public IMemoryRendering[] getRenderingsFromDebugTarget(IDebugTarget target)
 	{
 		ArrayList ret = new ArrayList();
 		for (int i=0; i<fRenderings.size(); i++)
 		{
 			if (fRenderings.get(i) instanceof IMemoryRendering)
 			{
 				IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
 				if (rendering.getMemoryBlock().getDebugTarget() == target)
 				{
 					ret.add(rendering);
 				}
 			}
 		}

 		return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
 	}


 	public IMemoryRendering[] getRenderingsFromMemoryBlock(IMemoryBlock block)
 	{
 		ArrayList ret = new ArrayList();
 		for (int i=0; i<fRenderings.size(); i++)
 		{
 			if (fRenderings.get(i) instanceof IMemoryRendering)
 			{
 				IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
 				if (rendering.getMemoryBlock() == block)
 				{
 					ret.add(rendering);
 				}
 			}
 		}

 		return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
 	}


 	public void handleDebugEvents(DebugEvent[] events) {

 		for (int i=0; i < events.length; i++)
 			handleDebugEvent(events[i]);

 	}

 	public void handleDebugEvent(DebugEvent event) {
 		Object obj = event.getSource();
 		IDebugTarget dt = null;

 		if (event.getKind() == DebugEvent.TERMINATE)
 		{
 			// a terminate event could happen from an IThread or IDebugTarget
 			// Only handle terminate event from debug target
 			if (obj instanceof IDebugTarget)
 			{
 				dt = ((IDebugTarget)obj);

 				// returns empty array if dt == null
 				IMemoryRendering[] deletedrendering = getRenderingsFromDebugTarget(dt);

 				for (int i=0; i<deletedrendering.length; i++)
 				{
 					removeMemoryBlockRendering(deletedrendering[i].getMemoryBlock(), deletedrendering[i].getRenderingId());
 					fViewPane.removeMemoryRendering(deletedrendering[i]);
 				}
 			}
 		}
 	}

 	public void dispose()
 	{
 		// remove all renderings
 		fRenderings.clear();

 		String secondaryId = getViewSiteSecondaryId();
 		if (secondaryId != null)
 		{
 			// do not save renderings if this is not the primary rendering view
 			String prefid = getPrefId();
 			Preferences prefs = DebugUIPlugin.getDefault().getPluginPreferences();
 			prefs.setToDefault(prefid);
 		}

 		DebugPlugin.getDefault().removeDebugEventListener(this);
 	}

 	/**
 	 * Store renderings as preferences.  If renderings are stored, renderings
 	 * can be persisted even after the memory view is closed.
 	 */
 	private void storeRenderings()
 	{
 		Preferences prefs = DebugUIPlugin.getDefault().getPluginPreferences();
 		String renderingsStr= ""; //$NON-NLS-1$
 		try {
 			renderingsStr= getRenderingsAsXML();
 		} catch (IOException e) {
 			DebugUIPlugin.log(e);
 		} catch (ParserConfigurationException e) {
 			DebugUIPlugin.log(e);
 		} catch (TransformerException e) {
 			DebugUIPlugin.log(e);
 		}

 		String prefid = getPrefId();

 		if (renderingsStr != null)
 			prefs.setValue(prefid, renderingsStr);
 		else
 			prefs.setToDefault(prefid);
 	}

 	private String getPrefId() {
 		// constructs id based on memory view's secondary id + the rendering view pane id
 		// format:  secondaryId:viewPaneId
 		StringBuffer id = new StringBuffer();
 		IMemoryRenderingSite renderingSite = fViewPane.getMemoryRenderingSite();
 		IWorkbenchPartSite ps = renderingSite.getSite();
 		if (ps instanceof IViewSite)
 		{
 			IViewSite vs = (IViewSite)ps;
 			String secondaryId = vs.getSecondaryId();
 			if (secondaryId != null)
 			{
 				id.append(secondaryId);
 				id.append(":"); //$NON-NLS-1$
 			}

 		}
 		id.append(fViewPane.getId());
 		String prefId = id.toString();
 		return prefId;
 	}

 	/**
 	 * Convert renderings to xml text
 	 * @return
 	 * @throws IOException
 	 * @throws ParserConfigurationException
 	 * @throws TransformerException
 	 */
 	private String getRenderingsAsXML() throws IOException, ParserConfigurationException, TransformerException {
 		IMemoryRendering[] renderings= (IMemoryRendering[])fRenderings.toArray(new IMemoryRendering[fRenderings.size()]);

 		if (renderings.length == 0)
 			return null;

 		Document document= LaunchManager.getDocument();
 		Element rootElement= document.createElement(RENDERINGS_TAG);
 		document.appendChild(rootElement);
 		for (int i = 0; i < renderings.length; i++) {
 			IMemoryRendering rendering= renderings[i];
 			Element element= document.createElement(MEMORY_RENDERING_TAG);
 			element.setAttribute(MEMORY_BLOCK, Integer.toString(rendering.getMemoryBlock().hashCode()));
 			element.setAttribute(RENDERING_ID, rendering.getRenderingId());
 			rootElement.appendChild(element);
 		}
 		return LaunchManager.serializeDocument(document);
 	}

 	/**
 	 * Load renderings currently stored.
 	 */
 	private void loadPersistedRenderings(String prefId) {
 		String renderingsStr= DebugUIPlugin.getDefault().getPluginPreferences().getString(prefId);
 		if (renderingsStr.length() == 0) {
 			return;
 		}
 		Element root;
 		try {
 			root = DebugPlugin.parseDocument(renderingsStr);
 		} catch (CoreException e) {
 			DebugUIPlugin.logErrorMessage("An exception occurred while loading memory renderings."); //$NON-NLS-1$
 			return;
 		}
 		if (!root.getNodeName().equals(RENDERINGS_TAG)) {
 			DebugUIPlugin.logErrorMessage("Invalid format encountered while loading memory renderings."); //$NON-NLS-1$
 			return;
 		}
 		NodeList list= root.getChildNodes();
 		boolean renderingsAdded= false;
 		for (int i= 0, numItems= list.getLength(); i < numItems; i++) {
 			Node node= list.item(i);
 			if (node.getNodeType() == Node.ELEMENT_NODE) {
 				Element element= (Element) node;
 				if (!element.getNodeName().equals(MEMORY_RENDERING_TAG)) {
 					DebugUIPlugin.logErrorMessage("Invalid XML element encountered while loading memory rendering."); //$NON-NLS-1$
 					continue;
 				}
 				String memoryBlockHashCode= element.getAttribute(MEMORY_BLOCK);
 				String renderingId = element.getAttribute(RENDERING_ID);

 				IMemoryBlock[] memoryBlocks = DebugPlugin.getDefault().getMemoryBlockManager().getMemoryBlocks();
 				IMemoryBlock memoryBlock = null;
 				for (int j=0; j<memoryBlocks.length; j++)
 				{
 					if (Integer.toString(memoryBlocks[j].hashCode()).equals(memoryBlockHashCode))
 						memoryBlock = memoryBlocks[j];
 				}

 				if (memoryBlock != null)
 				{
 					IMemoryRenderingType[] types  = DebugUITools.getMemoryRenderingManager().getRenderingTypes(memoryBlock);
 					IMemoryRenderingType type = null;
 					for (int k=0; k<types.length; k++)
 					{
 						if (types[k].getId().equals(renderingId))
 							type = types[k];
 					}

 					// if memory block is not found, the rendering is no longer valid
 					// simply ignore the rendering
 					if (type != null)
 					{
 						try {

 							IMemoryRendering rendering = type.createRendering();
 							if (rendering != null)
 							{
 								rendering.init(fViewPane, memoryBlock);
 								if (!fRenderings.contains(rendering))
 								{
 								    fRenderings.add(rendering);
 								    renderingsAdded= true;
 								}
 							}
 						} catch (CoreException e1) {
 							DebugUIPlugin.log(e1);
 						}
 					}
 				}
 			}
 		}
 		if (renderingsAdded) {
 			DebugPlugin.getDefault().addDebugEventListener(this);
 		}
 	}

 	/**
 	 * @return secondary id, or null if not available
 	 */
 	private String getViewSiteSecondaryId()
 	{
 		IMemoryRenderingSite renderingSite = fViewPane.getMemoryRenderingSite();
 		IWorkbenchPartSite ps = renderingSite.getSite();
 		if (ps instanceof IViewSite)
 		{
 			IViewSite vs = (IViewSite)ps;
 			String secondaryId = vs.getSecondaryId();
 			return secondaryId;
 		}
 		return null;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2004, 2006 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.debug.internal.ui.views.memory;

	import java.io.IOException;
	import java.util.ArrayList;

	import javax.xml.parsers.ParserConfigurationException;
	import javax.xml.transform.TransformerException;

	import org.eclipse.core.runtime.CoreException;
	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.IDebugTarget;
	import org.eclipse.debug.core.model.IMemoryBlock;
	import org.eclipse.debug.internal.core.LaunchManager;
	import org.eclipse.debug.internal.ui.DebugUIPlugin;
	import org.eclipse.debug.ui.DebugUITools;
	import org.eclipse.debug.ui.memory.IMemoryRendering;
	import org.eclipse.debug.ui.memory.IMemoryRenderingContainer;
	import org.eclipse.debug.ui.memory.IMemoryRenderingSite;
	import org.eclipse.debug.ui.memory.IMemoryRenderingType;
	import org.eclipse.ui.IViewSite;
	import org.eclipse.ui.IWorkbenchPartSite;
	import org.w3c.dom.Document;
	import org.w3c.dom.Element;
	import org.w3c.dom.Node;
	import org.w3c.dom.NodeList;

	/**
	* A View Pane Rendering Manager manages all the rendering from a view pane.
	* It is responsible for handling debug events and removing renderings
	* from the view pane as a debug session is terminated.
	* In addition, the rendering manager is responsible for persisting memory renderings.
	* Renderings need to be persisted when the memory view is disposed. If the view is
	* opened again, the same set of renderings will be created in the view pane if
	* the renderings are still valid.
	* @since 3.1
	*/
	public class ViewPaneRenderingMgr implements IDebugEventSetListener{

	private ArrayList fRenderings = new ArrayList();
	private IMemoryRenderingContainer fViewPane;

	private static final String RENDERINGS_TAG = "persistedMemoryRenderings"; //$NON-NLS-1$
	private static final String MEMORY_RENDERING_TAG = "memoryRendering"; //$NON-NLS-1$
	private static final String MEMORY_BLOCK = "memoryBlock"; //$NON-NLS-1$
	private static final String RENDERING_ID = "renderingId"; //$NON-NLS-1$

	public ViewPaneRenderingMgr(IMemoryRenderingContainer viewPane)
	{
	fViewPane = viewPane;
	loadPersistedRenderings(getPrefId());
	}

	public void removeMemoryBlockRendering(IMemoryBlock mem, String renderingId)
	{
	if(fRenderings == null)
	return;

	IMemoryRendering[] toRemove = getRenderings(mem, renderingId);

	for (int i=0; i<toRemove.length; i++)
	{
	fRenderings.remove(toRemove[i]);

	// remove listener after the last memory block has been removed
	if (fRenderings.size() == 0)
	{
	DebugPlugin.getDefault().removeDebugEventListener(this);
	}
	}

	storeRenderings();
	}


	public void addMemoryBlockRendering(IMemoryRendering rendering) {

	// do not allow duplicated objects
	if (fRenderings.contains(rendering))
	return;

	fRenderings.add(rendering);

	// add listener for the first memory block added
	if (fRenderings.size() == 1)
	{
	DebugPlugin.getDefault().addDebugEventListener(this);
	}

	storeRenderings();
	}


	public void removeMemoryBlockRendering(IMemoryRendering rendering) {
	if(rendering == null)
	return;

	if(!fRenderings.contains(rendering))
	return;

	fRenderings.remove(rendering);

	// remove listener after the last memory block has been removed
	if (fRenderings.size() == 0)
	{
	DebugPlugin.getDefault().removeDebugEventListener(this);
	}

	storeRenderings();
	}

	public IMemoryRendering[] getRenderings(IMemoryBlock mem, String renderingId)
	{
	if (renderingId == null)
	{
	return getRenderingsFromMemoryBlock(mem);
	}

	ArrayList ret = new ArrayList();
	for (int i=0; i<fRenderings.size(); i++)
	{
	if (fRenderings.get(i) instanceof IMemoryRendering)
	{
	IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
	if (rendering.getMemoryBlock() == mem && renderingId.equals(rendering.getRenderingId()))
	{
	ret.add(rendering);
	}
	}
	}

	return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
	}

	public IMemoryRendering[] getRenderings()
	{
	return (IMemoryRendering[])fRenderings.toArray(new IMemoryRendering[fRenderings.size()]);
	}

	public IMemoryRendering[] getRenderingsFromDebugTarget(IDebugTarget target)
	{
	ArrayList ret = new ArrayList();
	for (int i=0; i<fRenderings.size(); i++)
	{
	if (fRenderings.get(i) instanceof IMemoryRendering)
	{
	IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
	if (rendering.getMemoryBlock().getDebugTarget() == target)
	{
	ret.add(rendering);
	}
	}
	}

	return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
	}


	public IMemoryRendering[] getRenderingsFromMemoryBlock(IMemoryBlock block)
	{
	ArrayList ret = new ArrayList();
	for (int i=0; i<fRenderings.size(); i++)
	{
	if (fRenderings.get(i) instanceof IMemoryRendering)
	{
	IMemoryRendering rendering = (IMemoryRendering)fRenderings.get(i);
	if (rendering.getMemoryBlock() == block)
	{
	ret.add(rendering);
	}
	}
	}

	return (IMemoryRendering[])ret.toArray(new IMemoryRendering[ret.size()]);
	}



	public void handleDebugEvents(DebugEvent[] events) {

	for (int i=0; i < events.length; i++)
	handleDebugEvent(events[i]);

	}

	public void handleDebugEvent(DebugEvent event) {
	Object obj = event.getSource();
	IDebugTarget dt = null;

	if (event.getKind() == DebugEvent.TERMINATE)
	{
	// a terminate event could happen from an IThread or IDebugTarget
	// Only handle terminate event from debug target
	if (obj instanceof IDebugTarget)
	{
	dt = ((IDebugTarget)obj);

	// returns empty array if dt == null
	IMemoryRendering[] deletedrendering = getRenderingsFromDebugTarget(dt);

	for (int i=0; i<deletedrendering.length; i++)
	{
	removeMemoryBlockRendering(deletedrendering[i].getMemoryBlock(), deletedrendering[i].getRenderingId());
	fViewPane.removeMemoryRendering(deletedrendering[i]);
	}
	}
	}
	}

	public void dispose()
	{
	// remove all renderings
	fRenderings.clear();

	String secondaryId = getViewSiteSecondaryId();
	if (secondaryId != null)
	{
	// do not save renderings if this is not the primary rendering view
	String prefid = getPrefId();
	Preferences prefs = DebugUIPlugin.getDefault().getPluginPreferences();
	prefs.setToDefault(prefid);
	}

	DebugPlugin.getDefault().removeDebugEventListener(this);
	}

	/**
	* Store renderings as preferences. If renderings are stored, renderings
	* can be persisted even after the memory view is closed.
	*/
	private void storeRenderings()
	{
	Preferences prefs = DebugUIPlugin.getDefault().getPluginPreferences();
	String renderingsStr= ""; //$NON-NLS-1$
	try {
	renderingsStr= getRenderingsAsXML();
	} catch (IOException e) {
	DebugUIPlugin.log(e);
	} catch (ParserConfigurationException e) {
	DebugUIPlugin.log(e);
	} catch (TransformerException e) {
	DebugUIPlugin.log(e);
	}

	String prefid = getPrefId();

	if (renderingsStr != null)
	prefs.setValue(prefid, renderingsStr);
	else
	prefs.setToDefault(prefid);
	}

	private String getPrefId() {
	// constructs id based on memory view's secondary id + the rendering view pane id
	// format: secondaryId:viewPaneId
	StringBuffer id = new StringBuffer();
	IMemoryRenderingSite renderingSite = fViewPane.getMemoryRenderingSite();
	IWorkbenchPartSite ps = renderingSite.getSite();
	if (ps instanceof IViewSite)
	{
	IViewSite vs = (IViewSite)ps;
	String secondaryId = vs.getSecondaryId();
	if (secondaryId != null)
	{
	id.append(secondaryId);
	id.append(":"); //$NON-NLS-1$
	}

	}
	id.append(fViewPane.getId());
	String prefId = id.toString();
	return prefId;
	}

	/**
	* Convert renderings to xml text
	* @return
	* @throws IOException
	* @throws ParserConfigurationException
	* @throws TransformerException
	*/
	private String getRenderingsAsXML() throws IOException, ParserConfigurationException, TransformerException {
	IMemoryRendering[] renderings= (IMemoryRendering[])fRenderings.toArray(new IMemoryRendering[fRenderings.size()]);

	if (renderings.length == 0)
	return null;

	Document document= LaunchManager.getDocument();
	Element rootElement= document.createElement(RENDERINGS_TAG);
	document.appendChild(rootElement);
	for (int i = 0; i < renderings.length; i++) {
	IMemoryRendering rendering= renderings[i];
	Element element= document.createElement(MEMORY_RENDERING_TAG);
	element.setAttribute(MEMORY_BLOCK, Integer.toString(rendering.getMemoryBlock().hashCode()));
	element.setAttribute(RENDERING_ID, rendering.getRenderingId());
	rootElement.appendChild(element);
	}
	return LaunchManager.serializeDocument(document);
	}

	/**
	* Load renderings currently stored.
	*/
	private void loadPersistedRenderings(String prefId) {
	String renderingsStr= DebugUIPlugin.getDefault().getPluginPreferences().getString(prefId);
	if (renderingsStr.length() == 0) {
	return;
	}
	Element root;
	try {
	root = DebugPlugin.parseDocument(renderingsStr);
	} catch (CoreException e) {
	DebugUIPlugin.logErrorMessage("An exception occurred while loading memory renderings."); //$NON-NLS-1$
	return;
	}
	if (!root.getNodeName().equals(RENDERINGS_TAG)) {
	DebugUIPlugin.logErrorMessage("Invalid format encountered while loading memory renderings."); //$NON-NLS-1$
	return;
	}
	NodeList list= root.getChildNodes();
	boolean renderingsAdded= false;
	for (int i= 0, numItems= list.getLength(); i < numItems; i++) {
	Node node= list.item(i);
	if (node.getNodeType() == Node.ELEMENT_NODE) {
	Element element= (Element) node;
	if (!element.getNodeName().equals(MEMORY_RENDERING_TAG)) {
	DebugUIPlugin.logErrorMessage("Invalid XML element encountered while loading memory rendering."); //$NON-NLS-1$
	continue;
	}
	String memoryBlockHashCode= element.getAttribute(MEMORY_BLOCK);
	String renderingId = element.getAttribute(RENDERING_ID);

	IMemoryBlock[] memoryBlocks = DebugPlugin.getDefault().getMemoryBlockManager().getMemoryBlocks();
	IMemoryBlock memoryBlock = null;
	for (int j=0; j<memoryBlocks.length; j++)
	{
	if (Integer.toString(memoryBlocks[j].hashCode()).equals(memoryBlockHashCode))
	memoryBlock = memoryBlocks[j];
	}

	if (memoryBlock != null)
	{
	IMemoryRenderingType[] types = DebugUITools.getMemoryRenderingManager().getRenderingTypes(memoryBlock);
	IMemoryRenderingType type = null;
	for (int k=0; k<types.length; k++)
	{
	if (types[k].getId().equals(renderingId))
	type = types[k];
	}

	// if memory block is not found, the rendering is no longer valid
	// simply ignore the rendering
	if (type != null)
	{
	try {

	IMemoryRendering rendering = type.createRendering();
	if (rendering != null)
	{
	rendering.init(fViewPane, memoryBlock);
	if (!fRenderings.contains(rendering))
	{
	fRenderings.add(rendering);
	renderingsAdded= true;
	}
	}
	} catch (CoreException e1) {
	DebugUIPlugin.log(e1);
	}
	}
	}
	}
	}
	if (renderingsAdded) {
	DebugPlugin.getDefault().addDebugEventListener(this);
	}
	}

	/**
	* @return secondary id, or null if not available
	*/
	private String getViewSiteSecondaryId()
	{
	IMemoryRenderingSite renderingSite = fViewPane.getMemoryRenderingSite();
	IWorkbenchPartSite ps = renderingSite.getSite();
	if (ps instanceof IViewSite)
	{
	IViewSite vs = (IViewSite)ps;
	String secondaryId = vs.getSecondaryId();
	return secondaryId;
	}
	return null;
	}
	}