1 | // |
2 | // Event.h |
3 | // |
4 | // Library: XML |
5 | // Package: DOM |
6 | // Module: DOMEvents |
7 | // |
8 | // Definition of the DOM Event class. |
9 | // |
10 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
11 | // and Contributors. |
12 | // |
13 | // SPDX-License-Identifier: BSL-1.0 |
14 | // |
15 | |
16 | |
17 | #ifndef DOM_Event_INCLUDED |
18 | #define DOM_Event_INCLUDED |
19 | |
20 | |
21 | #include "Poco/XML/XML.h" |
22 | #include "Poco/XML/XMLString.h" |
23 | #include "Poco/DOM/DOMObject.h" |
24 | |
25 | |
26 | namespace Poco { |
27 | namespace XML { |
28 | |
29 | |
30 | class EventTarget; |
31 | class Document; |
32 | |
33 | |
34 | class XML_API Event: public DOMObject |
35 | /// The Event interface is used to provide contextual information about an event |
36 | /// to the handler processing the event. An object which implements the Event |
37 | /// interface is generally passed as the first parameter to an event handler. |
38 | /// More specific context information is passed to event handlers by deriving |
39 | /// additional interfaces from Event which contain information directly relating |
40 | /// to the type of event they accompany. These derived interfaces are also implemented |
41 | /// by the object passed to the event listener. |
42 | { |
43 | public: |
44 | enum PhaseType |
45 | { |
46 | CAPTURING_PHASE = 1, /// The event is currently being evaluated at the target EventTarget. |
47 | AT_TARGET = 2, /// The current event phase is the bubbling phase. |
48 | BUBBLING_PHASE = 3 /// The current event phase is the capturing phase. |
49 | }; |
50 | |
51 | const XMLString& type() const; |
52 | /// The name of the event (case-insensitive). The name must be an XML name. |
53 | |
54 | EventTarget* target() const; |
55 | /// Used to indicate the EventTarget to which the event was originally dispatched. |
56 | |
57 | EventTarget* currentTarget() const; |
58 | /// Used to indicate the EventTarget whose EventListeners are currently being |
59 | /// processed. This is particularly useful during capturing and bubbling. |
60 | |
61 | PhaseType eventPhase() const; |
62 | /// Used to indicate which phase of event flow is currently being evaluated. |
63 | |
64 | bool bubbles() const; |
65 | /// Used to indicate whether or not an event is a bubbling event. |
66 | /// If the event can bubble the value is true, else the value is false. |
67 | |
68 | bool cancelable() const; |
69 | /// Used to indicate whether or not an event can have its default action |
70 | /// prevented. If the default action can be prevented the value is |
71 | /// true, else the value is false. |
72 | |
73 | Poco::UInt64 timeStamp() const; |
74 | /// Used to specify the time (in milliseconds relative to the epoch) at |
75 | /// which the event was created. Due to the fact that some |
76 | /// systems may not provide this information the value of timeStamp may |
77 | /// be not available for all events. When not available, a |
78 | /// value of 0 will be returned. Examples of epoch time are the time of the |
79 | /// system start or 0:0:0 UTC 1st January 1970. |
80 | /// This implementation always returns 0. |
81 | |
82 | void stopPropagation(); |
83 | /// The stopPropagation method is used prevent further propagation of an |
84 | /// event during event flow. If this method is called by |
85 | /// any EventListener the event will cease propagating through the tree. |
86 | /// The event will complete dispatch to all listeners on the |
87 | /// current EventTarget before event flow stops. This method may be used |
88 | /// during any stage of event flow. |
89 | |
90 | void preventDefault(); |
91 | /// If an event is cancelable, the preventDefault method is used to signify |
92 | /// that the event is to be canceled, meaning any default |
93 | /// action normally taken by the implementation as a result of |
94 | /// the event will not occur. If, during any stage of event flow, the |
95 | /// preventDefault method is called the event is canceled. Any default |
96 | /// action associated with the event will not occur. Calling |
97 | /// this method for a non-cancelable event has no effect. Once |
98 | /// preventDefault has been called it will remain in effect throughout |
99 | /// the remainder of the event's propagation. This method may be |
100 | /// used during any stage of event flow. |
101 | |
102 | void initEvent(const XMLString& eventType, bool canBubble, bool isCancelable); |
103 | /// The initEvent method is used to initialize the value of an |
104 | /// Event created through the DocumentEvent interface. This method |
105 | /// may only be called before the Event has been dispatched via the |
106 | /// dispatchEvent method, though it may be called multiple |
107 | /// times during that phase if necessary. If called multiple |
108 | /// times the final invocation takes precedence. If called from |
109 | /// a subclass of Event interface only the values specified in the |
110 | /// initEvent method are modified, all other attributes are left unchanged. |
111 | |
112 | void autoRelease(); |
113 | |
114 | protected: |
115 | Event(Document* pOwnerDocument, const XMLString& type); |
116 | Event(Document* pOwnerDocument, const XMLString& type, EventTarget* pTarget, bool canBubble, bool isCancelable); |
117 | ~Event(); |
118 | |
119 | bool isCanceled() const; |
120 | /// returns true if and only if the event has been cancelled. |
121 | |
122 | bool isStopped() const; |
123 | /// returns true if and only if propagation of the event has been stopped. |
124 | |
125 | void setTarget(EventTarget* pTarget); |
126 | /// sets the target |
127 | |
128 | void setCurrentPhase(PhaseType phase); |
129 | /// sets the current phase |
130 | |
131 | void setCurrentTarget(EventTarget* pTarget); |
132 | /// sets the current target |
133 | |
134 | private: |
135 | Document* _pOwner; |
136 | XMLString _type; |
137 | EventTarget* _pTarget; |
138 | EventTarget* _pCurrentTarget; |
139 | PhaseType _currentPhase; |
140 | bool _bubbles; |
141 | bool _cancelable; |
142 | bool _canceled; |
143 | bool _stopped; |
144 | |
145 | friend class AbstractNode; |
146 | }; |
147 | |
148 | |
149 | // |
150 | // inlines |
151 | // |
152 | inline const XMLString& Event::type() const |
153 | { |
154 | return _type; |
155 | } |
156 | |
157 | |
158 | inline EventTarget* Event::target() const |
159 | { |
160 | return _pTarget; |
161 | } |
162 | |
163 | |
164 | inline EventTarget* Event::currentTarget() const |
165 | { |
166 | return _pCurrentTarget; |
167 | } |
168 | |
169 | |
170 | inline Event::PhaseType Event::eventPhase() const |
171 | { |
172 | return _currentPhase; |
173 | } |
174 | |
175 | |
176 | inline bool Event::bubbles() const |
177 | { |
178 | return _bubbles; |
179 | } |
180 | |
181 | |
182 | inline bool Event::cancelable() const |
183 | { |
184 | return _cancelable; |
185 | } |
186 | |
187 | |
188 | inline Poco::UInt64 Event::timeStamp() const |
189 | { |
190 | return 0; |
191 | } |
192 | |
193 | |
194 | inline bool Event::isCanceled() const |
195 | { |
196 | return _canceled; |
197 | } |
198 | |
199 | |
200 | inline bool Event::isStopped() const |
201 | { |
202 | return _stopped; |
203 | } |
204 | |
205 | |
206 | } } // namespace Poco::XML |
207 | |
208 | |
209 | #endif // DOM_Event_INCLUDED |
210 | |