Implementation of the shared library view.

debug/org.eclipse.cdt.debug.ui/ChangeLog

@@ -1,3 +1,13 @@
+2003-01-17 Mikhail Khodjaiants
+	Implementation of the shared library view.
+	* LoadSymbolsActionDelegate.java
+	* SharedLibrariesView.java
+	* SharedLibrariesViewEventHandler.java
+	* CDTDebugModelPresentation.java
+	* CDebugImages.java
+	* plugin.properties
+	* plugin.xml
+	
 2003-01-16 Mikhail Khodjaiants
 	Implementing the Shared Libraries view.
 	* SharedLibrariesView.java

debug/org.eclipse.cdt.debug.ui/plugin.properties

@@ -52,3 +52,5 @@ CDebugActionGroup.name=C/C++ Debug
 SourcePropertyPage.name=Source Lookup
 
 DisassemblyEditor.name=Disassembly Editor
+
+LoadSymbolsAction.label=Load Symbols

debug/org.eclipse.cdt.debug.ui/plugin.xml

@@ -627,6 +627,43 @@
             </enablement>
          </action>
       </viewerContribution>
+      <viewerContribution
+            targetID="org.eclipse.cdt.debug.ui.SharedLibrariesView"
+            id="org.eclipse.cdt.debug.ui.SharedLibrariesViewPopupActions">
+         <action
+               label="%ShowFullPathsAction.label"
+               icon="icons/full/clcl16/show_paths.gif"
+               helpContextId="show_full_paths_action_context"
+               class="org.eclipse.cdt.debug.internal.ui.actions.ShowFullPathsAction"
+               menubarPath="renderGroup"
+               id="org.eclipse.cdt.debug.internal.ui.actions.ShowFullPathsAction">
+            <enablement>
+               <pluginState
+                     value="activated"
+                     id="org.eclipse.cdt.debug.ui">
+               </pluginState>
+            </enablement>
+         </action>
+      </viewerContribution>
+      <objectContribution
+            objectClass="org.eclipse.cdt.debug.core.model.ICSharedLibrary"
+            id="org.eclipse.cdt.debug.ui.SharedLibraryActions">
+         <action
+               label="%LoadSymbolsAction.label"
+               icon="icons/full/clcl16/load_symbols_co.gif"
+               helpContextId="breakpoint_properties_action_context"
+               class="org.eclipse.cdt.debug.internal.ui.actions.LoadSymbolsActionDelegate"
+               menubarPath="additions"
+               enablesFor="1"
+               id="org.eclipse.cdt.debug.internal.ui.actions.LoadSymbolsActionDelegate">
+            <enablement>
+               <pluginState
+                     value="activated"
+                     id="org.eclipse.cdt.debug.ui">
+               </pluginState>
+            </enablement>
+         </action>
+      </objectContribution>
    </extension>
    <extension
          point="org.eclipse.ui.viewActions">
@@ -748,6 +785,27 @@
             </enablement>
          </action>
       </viewContribution>
+      <viewContribution
+            targetID="org.eclipse.cdt.debug.ui.SharedLibrariesView"
+            id="org.eclipse.debug.ui.sharedLibrariesView.toolbar">
+         <action
+               id="org.eclipse.cdt.debug.internal.ui.actions.ShowFullPathsAction"
+               toolbarPath="renderGroup"
+               hoverIcon="icons/full/clcl16/show_paths.gif"
+               class="org.eclipse.cdt.debug.internal.ui.actions.ShowFullPathsAction"
+               disabledIcon="icons/full/dlcl16/show_paths.gif"
+               icon="icons/full/elcl16/show_parents.gif"
+               helpContextId="show_full_paths_action_context"
+               label="%ShowFullPathsAction.label"
+               tooltip="%ShowFullPathsAction.tooltip">
+            <enablement>
+               <pluginState
+                     value="activated"
+                     id="org.eclipse.cdt.debug.ui">
+               </pluginState>
+            </enablement>
+         </action>
+      </viewContribution>
    </extension>
    <extension
          point="org.eclipse.ui.editorActions">

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/CDTDebugModelPresentation.java

@@ -22,6 +22,7 @@ import org.eclipse.cdt.debug.core.model.ICBreakpoint;
 import org.eclipse.cdt.debug.core.model.ICDebugTargetType;
 import org.eclipse.cdt.debug.core.model.ICFunctionBreakpoint;
 import org.eclipse.cdt.debug.core.model.ICLineBreakpoint;
+import org.eclipse.cdt.debug.core.model.ICSharedLibrary;
 import org.eclipse.cdt.debug.core.model.ICValue;
 import org.eclipse.cdt.debug.core.model.ICWatchpoint;
 import org.eclipse.cdt.debug.core.model.IDummyStackFrame;
@@ -228,6 +229,10 @@ public class CDTDebugModelPresentation extends LabelProvider
 			{
 				return getVariableImage( (IVariable)element );
 			}
+			if ( element instanceof ICSharedLibrary )
+			{
+				return getSharedLibraryImage( (ICSharedLibrary)element );
+			}
 		}
 		catch( CoreException e )
 		{
@@ -244,6 +249,12 @@ public class CDTDebugModelPresentation extends LabelProvider
 		StringBuffer label = new StringBuffer();
 		try
 		{
+			if ( element instanceof ICSharedLibrary )
+			{
+				label.append( getSharedLibraryText( (ICSharedLibrary)element, showQualified ) );
+				return label.toString();
+			}
+			
 			if ( element instanceof IRegisterGroup )
 			{
 				label.append( ((IRegisterGroup)element).getName() );
@@ -478,6 +489,17 @@ public class CDTDebugModelPresentation extends LabelProvider
 		return label;
 	}
 
+	protected String getSharedLibraryText( ICSharedLibrary library, boolean qualified ) throws DebugException
+	{
+		String label = new String();
+		IPath path = new Path( library.getFileName() );
+		if ( !path.isEmpty() )
+			label += ( qualified ? path.toOSString() : path.lastSegment() );	
+		return label + MessageFormat.format( " (Start address: ''{0}''  End address: ''{1}'')", 
+									 		 new String[] { CDebugUtils.toHexAddressString( library.getStartAddress() ),
+									 		 				CDebugUtils.toHexAddressString( library.getEndAddress() ) } );
+	}
+
 	/**
 	 * Plug in the single argument to the resource String for the key to 
 	 * get a formatted resource String.
@@ -771,6 +793,18 @@ public class CDTDebugModelPresentation extends LabelProvider
 		return fDebugImageRegistry.get( new CImageDescriptor( DebugUITools.getImageDescriptor( IDebugUIConstants.IMG_OBJS_EXPRESSION ),  0 ) );
 	}
 
+	protected Image getSharedLibraryImage( ICSharedLibrary element ) throws DebugException
+	{
+		if ( element.areSymbolsLoaded() )
+		{
+			return CDebugUIPlugin.getImageDescriptorRegistry().get( new CImageDescriptor( CDebugImages.DESC_OBJS_LOADED_SHARED_LIBRARY,  0 ) );
+		}
+		else
+		{
+			return CDebugUIPlugin.getImageDescriptorRegistry().get( new CImageDescriptor( CDebugImages.DESC_OBJS_SHARED_LIBRARY,  0 ) );
+		}
+	}
+
 	protected DisassemblyEditorInput getDisassemblyEditorInput( ICAddressBreakpoint breakpoint )
 	{
 		IDebugTarget[] targets = DebugPlugin.getDefault().getLaunchManager().getDebugTargets();

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/CDebugImages.java

@@ -65,8 +65,8 @@ public class CDebugImages
 	public static final String IMG_OBJS_DISASSEMBLY = NAME_PREFIX + "disassembly_obj.gif";	//$NON-NLS-1$
 	public static final String IMG_OBJS_PROJECT = NAME_PREFIX + "project_obj.gif";	//$NON-NLS-1$
 	public static final String IMG_OBJS_FOLDER = NAME_PREFIX + "folder_obj.gif";	//$NON-NLS-1$
-	public static final String IMG_OBJS_LOADED_SHARED_LIBRARY = NAME_PREFIX + "sharedlibraryl_obj.gif";	//$NON-NLS-1$
-	public static final String IMG_OBJS_SHARED_LIBRARY = NAME_PREFIX + "sharedlibraryu_obj.gif";	//$NON-NLS-1$
+	public static final String IMG_OBJS_LOADED_SHARED_LIBRARY = NAME_PREFIX + "library_syms_obj.gif";	//$NON-NLS-1$
+	public static final String IMG_OBJS_SHARED_LIBRARY = NAME_PREFIX + "library_obj.gif";	//$NON-NLS-1$
 
 	public static final String IMG_LCL_TYPE_NAMES = NAME_PREFIX + "tnames_co.gif";	//$NON-NLS-1$
 	public static final String IMG_LCL_CHANGE_REGISTER_VALUE = NAME_PREFIX + "change_reg_value_co.gif";	//$NON-NLS-1$

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/actions/LoadSymbolsActionDelegate.java

@@ -0,0 +1,126 @@
+/*
+ *(c) Copyright QNX Software Systems Ltd. 2002.
+ * All Rights Reserved.
+ * 
+ */
+package org.eclipse.cdt.debug.internal.ui.actions;
+
+import org.eclipse.cdt.debug.core.model.ICSharedLibrary;
+import org.eclipse.cdt.debug.ui.CDebugUIPlugin;
+import org.eclipse.core.runtime.MultiStatus;
+import org.eclipse.debug.core.DebugException;
+import org.eclipse.jface.action.IAction;
+import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.swt.custom.BusyIndicator;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.ui.IObjectActionDelegate;
+import org.eclipse.ui.IWorkbenchPart;
+import org.eclipse.ui.IWorkbenchWindow;
+
+/**
+ * Enter type comment.
+ * 
+ * @since: Jan 17, 2003
+ */
+public class LoadSymbolsActionDelegate implements IObjectActionDelegate
+{
+	private ICSharedLibrary fLibrary = null;
+
+	/**
+	 * Constructor for LoadSymbolsActionDelegate.
+	 */
+	public LoadSymbolsActionDelegate()
+	{
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.IObjectActionDelegate#setActivePart(IAction, IWorkbenchPart)
+	 */
+	public void setActivePart( IAction action, IWorkbenchPart targetPart )
+	{
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.IActionDelegate#run(IAction)
+	 */
+	public void run( IAction action )
+	{
+		if ( getSharedLibrary() != null )
+		{
+			final MultiStatus ms = new MultiStatus( CDebugUIPlugin.getUniqueIdentifier(), 
+													DebugException.REQUEST_FAILED, "Unable to load symbols of shared library.", null ); 
+			BusyIndicator.showWhile( Display.getCurrent(), 
+									new Runnable()
+										{
+											public void run()
+											{
+												try
+												{
+													doAction( getSharedLibrary() );
+												}
+												catch( DebugException e )
+												{
+													ms.merge( e.getStatus() );
+												}
+											}
+										} );
+			if ( !ms.isOK() )
+			{
+				IWorkbenchWindow window = CDebugUIPlugin.getActiveWorkbenchWindow();
+				if ( window != null )
+				{
+					CDebugUIPlugin.errorDialog( "Operation failed.", ms );
+				}
+				else
+				{
+					CDebugUIPlugin.log( ms );
+				}
+			}
+
+		}
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.ui.IActionDelegate#selectionChanged(IAction, ISelection)
+	 */
+	public void selectionChanged( IAction action, ISelection selection )
+	{
+		if ( selection instanceof IStructuredSelection )
+		{
+			Object element = ((IStructuredSelection)selection).getFirstElement();
+			if ( element instanceof ICSharedLibrary )
+			{
+				boolean enabled = enablesFor( (ICSharedLibrary)element );
+				action.setEnabled( enabled );
+				if ( enabled )
+				{
+					setSharedLibrary( (ICSharedLibrary)element );
+					return;
+				}
+			}
+		}
+		action.setEnabled( false );
+		setSharedLibrary( null );
+	}
+
+	protected void doAction( ICSharedLibrary library ) throws DebugException
+	{
+		library.loadSymbols();
+	}
+
+	private boolean enablesFor( ICSharedLibrary library )
+	{
+		return ( library != null && !library.areSymbolsLoaded() );
+	}
+	
+	private void setSharedLibrary( ICSharedLibrary library )
+	{
+		fLibrary = library;
+	}
+	
+	protected ICSharedLibrary getSharedLibrary()
+	{
+		return fLibrary;
+	}
+}

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/AbstractDebugEventHandler.java

@@ -77,9 +77,7 @@ public abstract class AbstractDebugEventHandler implements IDebugEventSetListene
 	{
 		if ( isAvailable() )
 		{
-			final Object parent =
-				(
-					(ITreeContentProvider)getTreeViewer().getContentProvider()).getParent( element );
+			final Object parent = ((ITreeContentProvider)getTreeViewer().getContentProvider()).getParent( element );
 			// a parent can be null for a debug target or process that has not yet been associated
 			// with a launch
 			if ( parent != null )

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/sharedlibs/SharedLibrariesView.java

@@ -6,17 +6,13 @@
 package org.eclipse.cdt.debug.internal.ui.views.sharedlibs;
 
 import org.eclipse.cdt.debug.core.ICSharedLibraryManager;
-import org.eclipse.cdt.debug.core.model.ICSharedLibrary;
-import org.eclipse.cdt.debug.internal.core.CDebugUtils;
-import org.eclipse.cdt.debug.internal.ui.CDebugImages;
-import org.eclipse.cdt.debug.internal.ui.CImageDescriptor;
 import org.eclipse.cdt.debug.internal.ui.ICDebugHelpContextIds;
-import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandler;
-import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandlerView;
 import org.eclipse.cdt.debug.internal.ui.views.IDebugExceptionHandler;
-import org.eclipse.cdt.debug.ui.CDebugUIPlugin;
 import org.eclipse.debug.core.DebugException;
 import org.eclipse.debug.core.model.IDebugElement;
+import org.eclipse.debug.ui.AbstractDebugView;
+import org.eclipse.debug.ui.DebugUITools;
+import org.eclipse.debug.ui.IDebugModelPresentation;
 import org.eclipse.debug.ui.IDebugUIConstants;
 import org.eclipse.jface.action.IMenuManager;
 import org.eclipse.jface.action.IToolBarManager;
@@ -25,16 +21,10 @@ import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
-import org.eclipse.jface.viewers.ITableLabelProvider;
-import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.graphics.Image;
-import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.widgets.Composite;
-import org.eclipse.swt.widgets.Table;
-import org.eclipse.swt.widgets.TableColumn;
 import org.eclipse.ui.ISelectionListener;
 import org.eclipse.ui.IWorkbenchActionConstants;
 import org.eclipse.ui.IWorkbenchPart;
@@ -44,58 +34,50 @@ import org.eclipse.ui.IWorkbenchPart;
  * 
  * @since: Jan 16, 2003
  */
-public class SharedLibrariesView extends AbstractDebugEventHandlerView
+public class SharedLibrariesView extends AbstractDebugView
 								 implements ISelectionListener, 
 								 			IPropertyChangeListener, 
 								 			IDebugExceptionHandler
 {
 	/**
-	 * Enter type comment.
-	 * 
-	 * @since: Jan 16, 2003
+	 * Event handler for this view
 	 */
-	public class SharedLibrariesViewLabelProvider extends LabelProvider
-												  implements ITableLabelProvider
-	{
-		/* (non-Javadoc)
-		 * @see org.eclipse.jface.viewers.ITableLabelProvider#getColumnImage(Object, int)
-		 */
-		public Image getColumnImage( Object element, int columnIndex )
-		{
-			if ( columnIndex == 0 && element instanceof ICSharedLibrary )
-			{
-				if ( ((ICSharedLibrary)element).areSymbolsLoaded() )
-				{
-					return CDebugUIPlugin.getImageDescriptorRegistry().get( new CImageDescriptor( CDebugImages.DESC_OBJS_LOADED_SHARED_LIBRARY,  0 ) );
-				}
-				else
-				{
-					return CDebugUIPlugin.getImageDescriptorRegistry().get( new CImageDescriptor( CDebugImages.DESC_OBJS_SHARED_LIBRARY,  0 ) );
-				}
-			}
-			return null;
-		}
+	private SharedLibrariesViewEventHandler fEventHandler;
 
-		/* (non-Javadoc)
-		 * @see org.eclipse.jface.viewers.ITableLabelProvider#getColumnText(Object, int)
-		 */
-		public String getColumnText( Object element, int columnIndex )
+	/**
+	 * The model presentation used as the label provider for the tree viewer.
+	 */
+	private IDebugModelPresentation fModelPresentation;
+
+	/**
+	 * Sets the event handler for this view
+	 * 
+	 * @param eventHandler event handler
+	 */
+	protected void setEventHandler( SharedLibrariesViewEventHandler eventHandler )
+	{
+		fEventHandler = eventHandler;
+	}
+
+	/**
+	 * Returns the event handler for this view
+	 * 
+	 * @return The event handler for this view
+	 */
+	protected SharedLibrariesViewEventHandler getEventHandler()
+	{
+		return fEventHandler;
+	}
+
+	/**
+	 * @see IWorkbenchPart#dispose()
+	 */
+	public void dispose()
+	{
+		super.dispose();
+		if ( getEventHandler() != null )
 		{
-			if ( element instanceof ICSharedLibrary )
-			{
-				switch( columnIndex )
-				{
-					case 0:
-						return ((ICSharedLibrary)element).getFileName();
-					case 1:
-						return CDebugUtils.toHexAddressString( ((ICSharedLibrary)element).getStartAddress() );
-					case 2:
-						return CDebugUtils.toHexAddressString( ((ICSharedLibrary)element).getEndAddress() );
-					case 3:
-						return ( ((ICSharedLibrary)element).areSymbolsLoaded() ) ? "Yes" : "No";
-				}
-			}
-			return null;
+			getEventHandler().dispose();
 		}
 	}
 
@@ -105,25 +87,8 @@ public class SharedLibrariesView extends AbstractDebugEventHandlerView
 	protected Viewer createViewer( Composite parent )
 	{
 		TableViewer viewer = new TableViewer( parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL );
-
-		Table table = viewer.getTable();
-		table.setHeaderVisible( true );
-		table.setLinesVisible( true );
-		table.setLayoutData( new GridData( GridData.FILL_BOTH ) );
-
-		// Create the table columns
-		new TableColumn( table, SWT.NULL );
-		new TableColumn( table, SWT.NULL );
-		new TableColumn( table, SWT.NULL );
-		new TableColumn( table, SWT.NULL );
-		TableColumn[] columns = table.getColumns();
-		columns[0].setText( "Name" );
-		columns[1].setText( "Start Address" );
-		columns[2].setText( "End Address" );
-		columns[3].setText( "Symbols" );
-
 		viewer.setContentProvider( new SharedLibrariesViewContentProvider() );
-		viewer.setLabelProvider( new SharedLibrariesViewLabelProvider() );
+		viewer.setLabelProvider( getModelPresentation() );
 
 		// listen to selection in debug view
 		getSite().getPage().addSelectionListener( IDebugUIConstants.ID_DEBUG_VIEW, this );
@@ -235,8 +200,17 @@ public class SharedLibrariesView extends AbstractDebugEventHandlerView
 	 * @param viewer the viewer associated with this view
 	 * @return an event handler
 	 */
-	protected AbstractDebugEventHandler createEventHandler( Viewer viewer ) 
+	protected SharedLibrariesViewEventHandler createEventHandler( Viewer viewer ) 
 	{
 		return new SharedLibrariesViewEventHandler( this );
 	}	
+
+	protected IDebugModelPresentation getModelPresentation() 
+	{
+		if ( fModelPresentation == null ) 
+		{
+			fModelPresentation = DebugUITools.newDebugModelPresentation();
+		}
+		return fModelPresentation;
+	}
 }

debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/views/sharedlibs/SharedLibrariesViewEventHandler.java

@@ -6,24 +6,55 @@
 package org.eclipse.cdt.debug.internal.ui.views.sharedlibs;
 
 import org.eclipse.cdt.debug.core.model.ICSharedLibrary;
-import org.eclipse.cdt.debug.internal.ui.views.AbstractDebugEventHandler;
 import org.eclipse.debug.core.DebugEvent;
+import org.eclipse.debug.core.DebugPlugin;
+import org.eclipse.debug.core.IDebugEventSetListener;
 import org.eclipse.debug.ui.AbstractDebugView;
+import org.eclipse.jface.viewers.TableViewer;
 
 /**
  * Enter type comment.
  * 
  * @since: Jan 16, 2003
  */
-public class SharedLibrariesViewEventHandler extends AbstractDebugEventHandler
+public class SharedLibrariesViewEventHandler implements IDebugEventSetListener
 {
+	/**
+	 * This event handler's view
+	 */
+	private AbstractDebugView fView;
+
 	/**
 	 * Constructor for SharedLibrariesViewEventHandler.
 	 * @param view
 	 */
 	public SharedLibrariesViewEventHandler( AbstractDebugView view )
 	{
-		super( view );
+		setView( view );
+		DebugPlugin.getDefault().addDebugEventListener( this );
+	}
+
+	/**
+	 * @see IDebugEventSetListener#handleDebugEvents(DebugEvent[])
+	 */
+	public void handleDebugEvents( final DebugEvent[] events )
+	{
+		if ( !isAvailable() )
+		{
+			return;
+		}
+		Runnable r = new Runnable()
+		{
+			public void run()
+			{
+				if ( isAvailable() )
+				{
+					doHandleDebugEvents( events );
+				}
+			}
+		};
+
+		getView().asyncExec( r );
 	}
 
 	/* (non-Javadoc)
@@ -49,4 +80,80 @@ public class SharedLibrariesViewEventHandler extends AbstractDebugEventHandler
 			}
 		}
 	}
+
+	/**
+	 * Refresh the given element in the viewer - must be called in UI thread.
+	 */
+	protected void refresh( Object element )
+	{
+		if ( isAvailable() )
+		{
+			getView().showViewer();
+			getTableViewer().refresh( element );
+		}
+	}
+
+	/**
+	 * Refresh the viewer - must be called in UI thread.
+	 */
+	public void refresh()
+	{
+		if ( isAvailable() )
+		{
+			getView().showViewer();
+			getTableViewer().refresh();
+		}
+	}
+
+	/**
+	 * De-registers this event handler from the debug model.
+	 */
+	public void dispose()
+	{
+		DebugPlugin plugin = DebugPlugin.getDefault();
+		plugin.removeDebugEventListener( this );
+	}
+
+	/**
+	 * Returns the view this event handler is
+	 * updating.
+	 * 
+	 * @return debug view
+	 */
+	protected AbstractDebugView getView()
+	{
+		return fView;
+	}
+
+	/**
+	 * Sets the view this event handler is updating.
+	 * 
+	 * @param view debug view
+	 */
+	private void setView( AbstractDebugView view )
+	{
+		fView = view;
+	}
+
+	/**
+	 * Returns the viewer this event handler is updating.
+	 * 
+	 * @return viewer
+	 */
+	protected TableViewer getTableViewer()
+	{
+		return (TableViewer)getView().getViewer();
+	}
+
+	/**
+	 * Returns whether this event handler's viewer is
+	 * currently available.
+	 * 
+	 * @return whether this event handler's viewer is
+	 * currently available
+	 */
+	protected boolean isAvailable()
+	{
+		return getView().isAvailable();
+	}
 }