Mercurial > projects > dwt-addons
view dwtx/core/commands/AbstractHandler.d @ 104:04b47443bb01
Reworked the collection uses to make use of a wrapper collection that is compatible to the Java Collections.
These new wrappers now use the tango.util.containers instead of the tango.util.collections.
author | Frank Benoit <benoit@tionex.de> |
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date | Thu, 07 Aug 2008 15:01:33 +0200 |
parents | 46a6e0e6ccd4 |
children |
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/******************************************************************************* * Copyright (c) 2004, 2008 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 * Port to the D programming language: * Frank Benoit <benoit@tionex.de> *******************************************************************************/ module dwtx.core.commands.AbstractHandler; import dwtx.core.commands.common.EventManager; import dwtx.core.commands.IHandler2; import dwtx.core.commands.IHandlerListener; import dwtx.core.commands.HandlerEvent; import dwt.dwthelper.utils; /** * <p> * This class is a partial implementation of <code>IHandler</code>. This * abstract implementation provides support for handler listeners. You should * subclass from this method unless you want to implement your own listener * support. Subclasses should call * {@link AbstractHandler#fireHandlerChanged(HandlerEvent)}when the handler * changes. Subclasses can also override {@link AbstractHandler#isEnabled()} and * {@link AbstractHandler#isHandled()}. * </p> * * @since 3.1 */ public abstract class AbstractHandler : EventManager, IHandler2 { /** * Track this base class enabled state. * * @since 3.4 */ private bool baseEnabled = true; /** * @see IHandler#addHandlerListener(IHandlerListener) */ public void addHandlerListener(IHandlerListener handlerListener) { addListenerObject(cast(Object)handlerListener); } /** * The default implementation does nothing. Subclasses who attach listeners * to other objects are encouraged to detach them in this method. * * @see dwtx.core.commands.IHandler#dispose() */ public void dispose() { // Do nothing. } /** * Fires an event to all registered listeners describing changes to this * instance. * <p> * Subclasses may extend the definition of this method (i.e., if a different * type of listener can be attached to a subclass). This is used primarily * for support of <code>AbstractHandler</code> in * <code>dwtx.ui.workbench</code>, and clients should be wary of * overriding this behaviour. If this method is overridden, then the first * line of the method should be "<code>super.fireHandlerChanged(handlerEvent);</code>". * </p> * * @param handlerEvent * the event describing changes to this instance. Must not be * <code>null</code>. */ protected void fireHandlerChanged(HandlerEvent handlerEvent) { if (handlerEvent is null) { throw new NullPointerException(); } Object[] listeners = getListeners(); for (int i = 0; i < listeners.length; i++) { IHandlerListener listener = cast(IHandlerListener) listeners[i]; listener.handlerChanged(handlerEvent); } } /** * Whether this handler is capable of executing at this time. Subclasses may * override this method. If clients override this method they should also * consider overriding {@link #setEnabled(Object)} so they can be notified * about framework execution contexts. * * @return <code>true</code> * @see #setEnabled(Object) * @see #setBaseEnabled(bool) */ public bool isEnabled() { return baseEnabled; } /** * Allow the default {@link #isEnabled()} to answer our enabled state. It * will fire a HandlerEvent if necessary. If clients use this method they * should also consider overriding {@link #setEnabled(Object)} so they can * be notified about framework execution contexts. * * @param state * the enabled state * @since 3.4 */ protected void setBaseEnabled(bool state) { if (baseEnabled is state) { return; } baseEnabled = state; fireHandlerChanged(new HandlerEvent(this, true, false)); } /** * Called by the framework to allow the handler to update its enabled state * by extracting the same information available at execution time. Clients * may override if they need to extract information from the application * context. * * @param evaluationContext * the application context. May be <code>null</code> * @since 3.4 * @see #setBaseEnabled(bool) */ public void setEnabled(Object evaluationContext) { } /** * Whether this handler is capable of handling delegated responsibilities at * this time. Subclasses may override this method. * * @return <code>true</code> */ public bool isHandled() { return true; } /** * <p> * Returns true iff there is one or more IHandlerListeners attached to this * AbstractHandler. * </p> * <p> * Subclasses may extend the definition of this method (i.e., if a different * type of listener can be attached to a subclass). This is used primarily * for support of <code>AbstractHandler</code> in * <code>dwtx.ui.workbench</code>, and clients should be wary of * overriding this behaviour. If this method is overridden, then the return * value should include "<code>super.hasListeners() ||</code>". * </p> * * @return true iff there is one or more IHandlerListeners attached to this * AbstractHandler */ protected bool hasListeners() { return isListenerAttached(); } /** * @see IHandler#removeHandlerListener(IHandlerListener) */ public void removeHandlerListener(IHandlerListener handlerListener) { removeListenerObject(cast(Object)handlerListener); } }