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Java > Open Source Codes > org > swixml > converters > ConstraintsConverter


1 /*--
2  $Id: ConstraintsConverter.java,v 1.1 2004/03/01 07:55:59 wolfpaulus Exp $
3
4  Copyright (C) 2003-2004 Wolf Paulus.
5  All rights reserved.
6
7  Redistribution and use in source and binary forms, with or without
8  modification, are permitted provided that the following conditions
9  are met:
10
11  1. Redistributions of source code must retain the above copyright
12  notice, this list of conditions, and the following disclaimer.
13
14  2. Redistributions in binary form must reproduce the above copyright
15  notice, this list of conditions, and the disclaimer that follows
16  these conditions in the documentation and/or other materials provided
17  with the distribution.
18
19  3. The end-user documentation included with the redistribution,
20  if any, must include the following acknowledgment:
21         "This product includes software developed by the
22          SWIXML Project (http://www.swixml.org/)."
23  Alternately, this acknowledgment may appear in the software itself,
24  if and wherever such third-party acknowledgments normally appear.
25
26  4. The name "Swixml" must not be used to endorse or promote products
27  derived from this software without prior written permission. For
28  written permission, please contact <info_AT_swixml_DOT_org>
29
30  5. Products derived from this software may not be called "Swixml",
31  nor may "Swixml" appear in their name, without prior written
32  permission from the Swixml Project Management.
33
34  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
35  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
36  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
37  DISCLAIMED. IN NO EVENT SHALL THE SWIXML PROJECT OR ITS
38  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
41  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
42  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
43  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
44  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45  SUCH DAMAGE.
46  ====================================================================
47
48  This software consists of voluntary contributions made by many
49  individuals on behalf of the Swixml Project and was originally
50  created by Wolf Paulus <wolf_AT_swixml_DOT_org>. For more information
51  on the Swixml Project, please see <http://www.swixml.org/>.
52 */
53
54 package org.swixml.converters;
55
56 import org.jdom.Attribute;
57
58 import java.awt.*;
59 import java.lang.reflect.Field JavaDoc;
60
61 /**
62  * The <code>ConstraintsConverter</code> class defines a converter that returns Layout constants
63  * based on layout type and input string.
64  * <br>
65  * <h3>Examples for Valid XML attribute notations:</h3>
66  * <pre>
67  * <ul>
68  * <li>constraints="BorderLayout.NORTH"</li>
69  * </ul>
70  * </pre>
71  *
72  * @author <a HREF="mailto:wolf@paulus.com">Wolf Paulus</a>
73  * @version $Revision: 1.1 $*
74  * @see java.awt.LayoutManager
75
76  */
77
78 public class ConstraintsConverter {
79   /** converter's return type */
80   public static final Class JavaDoc TEMPLATE = Object JavaDoc.class;
81
82   /**
83    * Converts Strings into Layout constants.
84    * @param type <code>Class</code> Layout type
85    * @param attr <code>Attribute</code> value needs to provide String which is used for the conversion
86    * @return <code>Object</code> Layout constant
87    */
88   public static Object JavaDoc convert(final Class JavaDoc type, final Attribute attr) {
89     Object JavaDoc constrain = null;
90     if (attr != null) {
91       if (BorderLayout.class.equals( type )) {
92         String JavaDoc value = attr.getValue();
93         Field JavaDoc[] fields = BorderLayout.class.getFields();
94         for (int i = 0; i < fields.length; i++) {
95           if (value.endsWith( fields[i].getName() )) {
96             try {
97               constrain = fields[i].get( BorderLayout.class );
98             } catch (Exception JavaDoc e) {
99             }
100             break;
101           }
102         }
103       } else if (CardLayout.class.equals( type )) {
104         //
105 // CardLayout accepts only constraints of type String
106 //
107 constrain = attr.getValue();
108       }
109     }
110     return constrain;
111   }
112
113
114   /**
115    * A <code>Converters</code> conversTo method informs about the Class type the converter
116    * is returning when its <code>convert</code> method is called
117    * @return <code>Class</code> - the Class the converter is returning when its convert method is called
118    */
119   public Class JavaDoc convertsTo() {
120     return TEMPLATE;
121   }
122 }
123
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