1/*
2 * Copyright (c) 1999-2000, Eric Moon.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions, and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions, and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
27 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31
32// ObservableHandler.h
33// * PURPOSE
34//   Implementation of an observable BHandler.
35//
36// * HISTORY
37//   e.moon		19aug99		Begun.
38
39#ifndef __ObservableHandler_H__
40#define __ObservableHandler_H__
41
42#include <Handler.h>
43
44#include "observe.h"
45#include "IObservable.h"
46#include "MultiInvoker.h"
47
48#include "cortex_defs.h"
49__BEGIN_CORTEX_NAMESPACE
50
51class ObservableHandler :
52	public	BHandler,
53	public	IObservable,
54	private	MultiInvoker {
55
56	typedef	BHandler _inherited;
57
58public:											// *** deletion
59	// clients must call release() rather than deleting,
60	// to ensure that all observers are notified of the
61	// object's demise.  if the object has already been
62	// released, return an error.
63
64	virtual status_t release();
65
66public:											// *** ctor/dtor
67	virtual ~ObservableHandler();
68	ObservableHandler(
69		const char*							name=0);
70	ObservableHandler(
71		BMessage*								archive);
72
73public:											// *** accessors
74	// return true if release() has been called, false otherwise.
75	bool isReleased() const;
76
77protected:									// *** hooks
78	// sends M_OBSERVER_ADDED to the newly-added observer
79	virtual void observerAdded(
80		const BMessenger&				observer);
81
82	// sends M_OBSERVER_REMOVED to the newly-removed observer
83	virtual void observerRemoved(
84		const BMessenger&				observer);
85
86protected:									// *** internal operations
87	// call to send the given message to all observers.
88	// Responsibility for deletion of the message remains with
89	// the caller.
90	// * LOCKING: the BLooper must be locked.
91	virtual status_t notify(
92		BMessage*								message);
93
94	// sends M_RELEASE_OBSERVABLE
95	virtual void notifyRelease();
96
97public:											// *** BHandler
98	virtual void MessageReceived(
99		BMessage*								message);
100
101public:											// *** BArchivable
102	// * LOCKING: the BLooper must be locked.
103	virtual status_t Archive(
104		BMessage*								archive,
105		bool										deep=true) const;
106
107private:										// implementation
108	void _handleAddObserver(
109		BMessage*								message); //nyi
110
111	void _handleRemoveObserver(
112		BMessage*								message); //nyi
113
114private:										// members
115	bool											m_released;
116};
117
118__END_CORTEX_NAMESPACE
119#endif /*__ObservableHandler_H__*/
120
121