gecko-dev/java/webclient/src_moz/nsActions.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is RaptorCanvas.
*
* The Initial Developer of the Original Code is Kirk Baker and
* Ian Wilkinson. Portions created by Kirk Baker and Ian Wilkinson are
* Copyright (C) 1999 Kirk Baker and Ian Wilkinson. All
* Rights Reserved.
*
* Contributor(s): Kirk Baker <kbaker@eb.com>
* Ian Wilkinson <iw@ennoble.com>
* Ashutosh Kulkarni <ashuk@eng.sun.com>
* Mark Lin <mark.lin@eng.sun.com>
* Mark Goddard
* Ed Burns <edburns@acm.org>
*/
/*
* nsActions.h
*/
#ifndef nsActions_h___
#define nsActions_h___
#include "plevent.h"
/**
* Concrete subclasses of nsActionEvent are used to safely convey an
* action from Java to mozilla.
* This class is kind of like a subclass of the C based PLEvent struct,
* defined in
* <http://lxr.mozilla.org/mozilla/source/xpcom/threads/plevent.h#455>.
* Lifecycle
* nsActionEvent subclass instances are usually created in a JNI method
* implementation, such as
* Java_org_mozilla*NavigationImpl_nativeLoadURL(). In nativeLoadURL(),
* we create an instance of wsLoadURLEvent, which is a subclass of
* nsActionEvent, passing in the nsIWebShell instance, and the url
* string. The arguments to the nsActionEvent constructor vary from one
* subclass to the next, but they all have the property that they
* provide information used in the subclass's handleEvent()
* method.
* The nsActionEvent subclass is then cast to a PLEvent struct, and
* passed into either util_PostEvent() or util_PostSynchronous event,
* declared in ns_util.h. See the comments for those functions for
* information on how they deal with the nsActionEvent, cast as a
* PLEvent.
* During event processing in util_Post*Event, the subclass's
* handleEvent() method is called. This is where the appropriate action
* for that subclass takes place. For example for wsLoadURLEvent,
* handleEvent calls nsIWebShell::LoadURL().
* The life of an nsActionEvent subclass ends shortly after the
* handleEvent() method is called. This happens when mozilla calls
* nsActionEvent::destroyEvent(), which simply deletes the instance.
*/
class nsActionEvent {
public:
nsActionEvent ();
virtual ~nsActionEvent () {};
virtual void * handleEvent (void) = 0; //{ return nsnull;};
void destroyEvent (void) { delete this; };
operator PLEvent* () { return &mEvent; };
protected:
PLEvent mEvent;
};
#endif /* nsActions_h___ */
// EOF