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Java > Open Source Codes > com > gargoylesoftware > htmlunit > javascript > host > EventHandler


1 /*
2  * Copyright (c) 2002, 2005 Gargoyle Software Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are met:
6  *
7  * 1. Redistributions of source code must retain the above copyright notice,
8  * this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright notice,
10  * this list of conditions and the following disclaimer in the documentation
11  * and/or other materials provided with the distribution.
12  * 3. The end-user documentation included with the redistribution, if any, must
13  * include the following acknowledgment:
14  *
15  * "This product includes software developed by Gargoyle Software Inc.
16  * (http://www.GargoyleSoftware.com/)."
17  *
18  * Alternately, this acknowledgment may appear in the software itself, if
19  * and wherever such third-party acknowledgments normally appear.
20  * 4. The name "Gargoyle Software" must not be used to endorse or promote
21  * products derived from this software without prior written permission.
22  * For written permission, please contact info@GargoyleSoftware.com.
23  * 5. Products derived from this software may not be called "HtmlUnit", nor may
24  * "HtmlUnit" appear in their name, without prior written permission of
25  * Gargoyle Software Inc.
26  *
27  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
28  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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36  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37  */
38 package com.gargoylesoftware.htmlunit.javascript.host;
39
40 import org.apache.commons.logging.Log;
41 import org.apache.commons.logging.LogFactory;
42 import org.mozilla.javascript.BaseFunction;
43 import org.mozilla.javascript.Context;
44 import org.mozilla.javascript.Function;
45 import org.mozilla.javascript.JavaScriptException;
46 import org.mozilla.javascript.Scriptable;
47
48 import com.gargoylesoftware.htmlunit.html.HtmlElement;
49 import com.gargoylesoftware.htmlunit.javascript.SimpleScriptable;
50
51 /**
52  * Allows to wrap event handler code as Function object.
53  * @version $Revision: 100 $
54  * @author Marc Guillemot
55  */
56 public class EventHandler extends BaseFunction {
57     private static final long serialVersionUID = 3257850965406068787L;
58     
59     private final HtmlElement htmlElement_;
60     private final String JavaDoc jsSnippet_;
61     private Function realFunction_;
62
63     /**
64      * Builds a function that will execute the javascript code provided
65      * @param htmlElement the element for which the event is build
66      * @param jsSnippet the javascript code
67      */
68     public EventHandler(final HtmlElement htmlElement, final String JavaDoc jsSnippet) {
69         htmlElement_ = htmlElement;
70         jsSnippet_ = "function(event) {" + jsSnippet + "}";
71     }
72
73     /**
74      * The function call.
75      * @see org.mozilla.javascript.BaseFunction#call(Context, Scriptable, Scriptable, Object[])
76      */
77     public Object JavaDoc call(final Context cx, final Scriptable scope,
78         final Scriptable thisObj, final Object JavaDoc[] args)
79         throws JavaScriptException {
80
81         // the js object to which this event is attached has to be the scope
82 final SimpleScriptable jsObj = (SimpleScriptable) htmlElement_.getScriptObject();
83         // compile "just in time"
84 if (realFunction_ == null) {
85             realFunction_ = cx.compileFunction(jsObj, jsSnippet_, "event for " + htmlElement_, 1, null);
86         }
87
88         final Object JavaDoc result = realFunction_.call(cx, scope, thisObj, args);
89
90         return result;
91     }
92
93     /**
94      * @see org.mozilla.javascript.ScriptableObject#getDefaultValue(java.lang.Class)
95      * @param typeHint the type hint
96      * @return the js code of the function declaration
97      */
98     public Object JavaDoc getDefaultValue(final Class JavaDoc typeHint) {
99         return jsSnippet_;
100     }
101     
102     /**
103      *
104      * @see org.mozilla.javascript.IdScriptableObject#get(java.lang.String, org.mozilla.javascript.Scriptable)
105      */
106     public Object JavaDoc get(final String JavaDoc name, final Scriptable start) {
107         // quick and dirty
108 if ("toString".equals(name)) {
109             return new BaseFunction() {
110                 private static final long serialVersionUID = 3761409724511435061L;
111
112                 public Object JavaDoc call(final Context cx, final Scriptable scope,
113                         final Scriptable thisObj, final Object JavaDoc[] args) {
114                     return jsSnippet_;
115                 }
116             };
117         }
118
119         return super.get(name, start);
120     }
121     
122     /**
123      * Return the log
124      * @return The log.
125      */
126     protected final Log getLog() {
127         return LogFactory.getLog(getClass());
128     }
129 }
130
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