Java tutorial
/******************************************************************************* * Copyright (c) 2000, 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.cdt.debug.internal.ui.views; 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.IBasicPropertyConstants; import org.eclipse.jface.viewers.ITreeContentProvider; import org.eclipse.jface.viewers.StructuredSelection; import org.eclipse.jface.viewers.StructuredViewer; import org.eclipse.jface.viewers.TableTreeViewer; import org.eclipse.jface.viewers.TreeViewer; import org.eclipse.jface.viewers.Viewer; import org.eclipse.ui.IWorkbenchPage; import org.eclipse.ui.IWorkbenchWindow; import org.eclipse.ui.PlatformUI; /** * Handles debug events, updating a view and viewer. */ public abstract class AbstractDebugEventHandler implements IDebugEventSetListener { /** * This event handler's view */ private AbstractDebugView fView; /** * Constructs an event handler for the given view. * * @param view debug view */ public AbstractDebugEventHandler(AbstractDebugView view) { setView(view); DebugPlugin plugin = DebugPlugin.getDefault(); plugin.addDebugEventListener(this); } /** * Returns the active workbench page or <code>null</code> if none. */ protected IWorkbenchPage getActivePage() { IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow(); if (window == null) { return null; } return window.getActivePage(); } /** * @see IDebugEventSetListener#handleDebugEvents(DebugEvent[]) */ @Override public void handleDebugEvents(final DebugEvent[] events) { if (!isAvailable()) { return; } Runnable r = new Runnable() { @Override public void run() { if (isAvailable()) { if (isViewVisible()) { doHandleDebugEvents(events); } updateForDebugEvents(events); } } }; getView().asyncExec(r); } /** * Updates this view for the given debug events. Unlike * doHandleDebugEvents(DebugEvent[]) which is only called if the view is * visible, this method is always called. This allows the view to perform * updating that must always be performed, even when the view is not * visible. */ protected void updateForDebugEvents(DebugEvent[] events) { } /** * Implementation specific handling of debug events. * Subclasses should override. */ protected abstract void doHandleDebugEvents(DebugEvent[] events); /** * Helper method for inserting the given element in the tree viewer - * must be called in UI thread */ protected void insert(Object element) { TreeViewer viewer = getTreeViewer(); if (isAvailable() && viewer != null) { Object parent = ((ITreeContentProvider) viewer.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) { getView().showViewer(); viewer.add(parent, element); } } } /** * Helper method to remove the given element from the tree viewer - * must be called in UI thread. */ protected void remove(Object element) { TreeViewer viewer = getTreeViewer(); if (isAvailable() && viewer != null) { getView().showViewer(); viewer.remove(element); } } /** * Helper method to update the label of the given element - must be called in UI thread */ protected void labelChanged(Object element) { if (isAvailable()) { getView().showViewer(); getStructuredViewer().update(element, new String[] { IBasicPropertyConstants.P_TEXT }); } } /** * Refresh the given element in the viewer - must be called in UI thread. */ protected void refresh(Object element) { if (isAvailable()) { getView().showViewer(); getStructuredViewer().refresh(element); } } /** * Refresh the viewer - must be called in UI thread. */ public void refresh() { if (isAvailable()) { getView().showViewer(); getStructuredViewer().refresh(); } } /** * Helper method to select and reveal the given element - must be called in UI thread */ protected void selectAndReveal(Object element) { if (isAvailable()) { getViewer().setSelection(new StructuredSelection(element), true); } } /** * 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 this.fView; } /** * Sets the view this event handler is updating. * * @param view debug view */ private void setView(AbstractDebugView view) { this.fView = view; } /** * Returns the viewer this event handler is * updating. * * @return viewer */ protected Viewer getViewer() { return getView().getViewer(); } /** * Returns this event handler's viewer as a tree * viewer or <code>null</code> if none. * * @return this event handler's viewer as a tree * viewer or <code>null</code> if none */ protected TreeViewer getTreeViewer() { if (getViewer() instanceof TreeViewer) { return (TreeViewer) getViewer(); } return null; } /** * Returns this event handler's viewer as a table tree * viewer or <code>null</code> if none. * * @return this event handler's viewer as a table tree * viewer or <code>null</code> if none */ protected TableTreeViewer getTableTreeViewer() { if (getViewer() instanceof TableTreeViewer) { return (TableTreeViewer) getViewer(); } return null; } /** * Returns this event handler's viewer as a structured * viewer or <code>null</code> if none. * * @return this event handler's viewer as a structured * viewer or <code>null</code> if none */ protected StructuredViewer getStructuredViewer() { if (getViewer() instanceof StructuredViewer) { return (StructuredViewer) getViewer(); } return null; } /** * 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(); } /** * Returns whether this event handler's view is currently visible. * * @return whether this event handler's view is currently visible */ protected boolean isViewVisible() { return getView().isVisible(); } /** * Called when this event handler's view becomes visible. Default behavior * is to refresh the view. */ protected void viewBecomesVisible() { refresh(); } /** * Called when this event handler's view becomes hidden. Default behavior is * to do nothing. Subclasses may override. */ protected void viewBecomesHidden() { } }