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Java > Open Source Codes > com > jcorporate > expresso > services > taglib > TransitionName


1 package com.jcorporate.expresso.services.taglib;
2
3 /* ====================================================================
4  * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
5  *
6  * Copyright (c) 1995-2003 Jcorporate Ltd. All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
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16  * notice, this list of conditions and the following disclaimer in
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18  * distribution.
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20  * 3. The end-user documentation included with the redistribution,
21  * if any, must include the following acknowledgment:
22  * "This product includes software developed by Jcorporate Ltd.
23  * (http://www.jcorporate.com/)."
24  * Alternately, this acknowledgment may appear in the software itself,
25  * if and wherever such third-party acknowledgments normally appear.
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27  * 4. "Jcorporate" and product names such as "Expresso" must
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29  * software without prior written permission. For written permission,
30  * please contact info@jcorporate.com.
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32  * 5. Products derived from this software may not be called "Expresso",
33  * or other Jcorporate product names; nor may "Expresso" or other
34  * Jcorporate product names appear in their name, without prior
35  * written permission of Jcorporate Ltd.
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39  * of Jcorporate Ltd. For written permission, please contact
40  * partners@jcorporate.com.
41  *
42  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
43  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
44  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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57  * individuals on behalf of the Jcorporate Ltd. Contributions back
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60  * on Jcorporate Ltd. and its products, please see
61  * <http://www.jcorporate.com/>.
62  *
63  * Portions of this software are based upon other open source
64  * products and are subject to their respective licenses.
65  */
66
67 import com.jcorporate.expresso.core.controller.Transition;
68 import org.apache.log4j.Logger;
69
70 import javax.servlet.jsp.JspException JavaDoc;
71 import javax.servlet.jsp.tagext.TagSupport JavaDoc;
72 import java.io.IOException JavaDoc;
73
74 /**
75  * The TransitionName tag is what you insert at the value for the name of
76  * a submit button on a form where you wish for the transition to appear. This
77  * is necessary since a special button naming convention is used in Expresso.
78  * <p>For the 'value' attribute supply a JSTL-EL expression that evaluates to
79  * a Transition object, and the tag will output the button name from that</p>
80  * <p>Be sure to add the appropriate button hidden parameters after your submit
81  * button by using the 'buttonparams' tag.</p>
82  *
83  * @author Michael Rimov
84  * @version $Revision: 1.6 $ on $Date: 2004/11/17 20:48:21 $
85  */
86 public class TransitionName extends TagSupport JavaDoc {
87
88     private static final Logger log = Logger.getLogger(TransitionName.class);
89
90     /**
91      * JSTL EL expression
92      */
93     private String JavaDoc value;
94
95
96     public TransitionName() {
97     }
98
99     /**
100      * Get the JSTL expression for value.
101      *
102      * @return java.lang.String
103      */
104     public String JavaDoc getValue() {
105         return value;
106     }
107
108     /**
109      * Sets the value JSTL expression
110      *
111      * @param value the JSTL expression.
112      */
113     public void setValue(String JavaDoc value) {
114         this.value = value;
115     }
116
117     /**
118      * Does the actual grunt work.
119      *
120      * @return EVAL_PAGE
121      */
122     public int doEndTag() throws javax.servlet.jsp.JspException JavaDoc {
123         ELTagSupport support = ELTagSupport.getInstance();
124         Transition result = (Transition) support.evaluate("value", this.getValue(),
125                 Transition.class,
126                 this, this.pageContext);
127
128         if (result == null) {
129             throw new JspException JavaDoc("Unable to locate transition for expression: " + this.getValue());
130         }
131
132         String JavaDoc writeValue = "button_" + result.getName();
133
134         try {
135             pageContext.getOut().write(writeValue);
136         } catch (IOException JavaDoc ex1) {
137             log.error("I/O exception writing output value", ex1);
138             throw new JspException JavaDoc("I/O error");
139         }
140
141         return EVAL_PAGE;
142     }
143
144 }
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