LayoutConverter


1   /*--
2    $Id: LayoutConverter.java,v 1.1 2004/03/01 07:56:01 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  import org.swixml.Converter;
58  import org.swixml.Localizer;
59  import org.swixml.SwingEngine;
60  
61  import java.awt.*;
62  import java.lang.reflect.Field  ;
63  import java.util.StringTokenizer  ;
64  
65  /**
66   * The <code>LayoutConverter</code> class defines a converter that creates LayoutManager objects
67   * based on a provided String.
68   * <h3>Examples for Valid XML attribute notations:</h3>
69   * <pre>
70   * <p><b>FlowLayout</b><br>can be created with all 3 construtors:<br>
71   * <ul>
72   * <li>FlowLayout()</li>
73   * <li>FlowLayout(int align)</li>
74   * <li>FlowLayout(int align, int hgap, int vgap)</li>
75   * </ul>
76   *
77   * <ul>
78   * <li>BorderLayout()</li>
79   * <li>BorderLayout(int hgap, int vgap)</li>
80   * </ul>
81   *
82   * <ul>
83   * <li>GridBagLayout()</li>
84   * <li>GridBagLayout(rowWeights(0,0,1.0,0))</li>
85   * <li>GridBagLayout(colWeights(0.5, 0.5, 1.0, 99.9))</li>
86   * <li>GridBagLayout(columnWidths(5, 5, 10, 33))</li>
87   * <li>GridBagLayout(rowHeights(5, 5, 10, 33))</li>
88   * </ul>
89   *
90   * </pre>
91   *
92   * @author <a HREF="mailto:wolf@paulus.com">Wolf Paulus</a>
93   *
94   * @version $Revision: 1.1 $
95   *
96   * @see java.awt.LayoutManager
97   * @see org.swixml.ConverterLibrary
98  
99   */
100 public class LayoutConverter implements Converter {
101   /** converter's return type */
102   public static final Class   TEMPLATE = LayoutManager.class;
103 
104   public static final String   FLOW_LAYOUT = "flowlayout";
105   public static final String   BORDER_LAYOUT = "borderlayout";
106   public static final String   GRID_LAYOUT = "gridlayout";
107   public static final String   GRIDBAG_LAYOUT = "gridbaglayout";
108   public static final String   CARD_LAYOUT = "cardlayout";
109 
110   /**
111    * Convert the specified input object into an output object of the
112    * specified type.
113    * <pre>
114    * <p><b>FlowLayout</b><br>can be created with all 3 construtors:<br>
115    * <ul>
116    * <li>FlowLayout()</li>
117    * <li>FlowLayout(int align)</li>
118    * <li>FlowLayout(int align, int hgap, int vgap)</li>
119    * </ul>
120    *
121    * <ul>
122    * <li>BorderLayout()</li>
123    * <li>BorderLayout(int hgap, int vgap)</li>
124    * </ul>
125    *
126    * <ul>
127    * <li>BoxLayout: see Box tag</li>
128    * </ul>
129    *
130    * <ul>
131    * <li>GridLayout()</li>
132    * <li>GridLayout(int rows, int cols)</li>
133    * <li>GridLayout(int rows, int cols, int hgap, int vgap) </li>
134    * </ul>
135    *
136    * <ul>
137    * <li>GridBagLayout()</li>
138    * <li>GridBagLayout(rowWeights(0,0,1.0,0))</li>
139    * <li>GridBagLayout(colWeights(0.5, 0.5, 1.0, 99.9))</li>
140    * <li>GridBagLayout(columnWidths(5, 5, 10, 33))</li>
141    * <li>GridBagLayout(rowHeights(5, 5, 10, 33))</li>
142    * </ul>
143    *
144    * <ul>
145    * <li>CardLayout() - Creates a new card layout with gaps of size zero.</li>
146    * <li>CardLayout(int hgap, int vgap) - Creates a new card layout with the specified horizontal and vertical gaps.</li>
147    * </ul>
148    * Here is how to access the card layout manager of a component installed by SwixML
149    * (CardLayout)((Container)swingEngine.find("id_of_my_CLed_comp")).getLayout()
150    *
151    * </pre>
152    * @param type <code>Class</code> not used
153    * @param attr <code>Attribute</code> value is needed for conversion
154    * @return <code>Object</code>
155    */
156   public Object   convert( final Class   type, final Attribute attr, final Localizer localizer ) {
157     LayoutManager lm = null;
158     StringTokenizer   st = new StringTokenizer  ( attr.getValue(), "(,)" );
159     String   s = st.nextToken().trim();  // here, s should contain the LayoutManager's name
160     if (s != null) {
161       s = s.toLowerCase();
162       if (s.equals( LayoutConverter.FLOW_LAYOUT )) {
163         //
164         //  FLOW_LAYOUT
165         //
166         try {
167           if (st.hasMoreTokens()) {
168             //
169             //  First FlowLayout parameter might be a pre-defined constant's name
170             //
171             Object   o = PrimitiveConverter.conv( null, new Attribute( "NA", st.nextToken() ), localizer );
172             int[] para = Util.ia( st );
173             //
174             //  Remaining paramters should be integer values
175             //
176             if (para.length < 2)
177               lm = new FlowLayout( Integer.valueOf( o.toString() ).intValue() );
178             else
179               lm = new FlowLayout( Integer.valueOf( o.toString() ).intValue(), para[ 0 ], para[ 1 ] );
180           }
181         } catch (Exception   e) {
182         }
183         if (lm == null) {
184           lm = new FlowLayout();
185         }
186       } else if (s.equals( LayoutConverter.BORDER_LAYOUT )) {
187         //
188         //  BORDER_LAYOUT
189         //
190         int[] para = Util.ia( st );
191         if (para.length < 2)
192           lm = new BorderLayout();
193         else
194           lm = new BorderLayout( para[ 0 ], para[ 1 ] );
195       } else if (s.equals( LayoutConverter.GRID_LAYOUT )) {
196         //
197         //  GRID_LAYOUT
198         //
199         int[] para = Util.ia( st );
200         if (4 <= para.length)
201           lm = new GridLayout( para[ 0 ], para[ 1 ], para[ 2 ], para[ 3 ] );
202         else if (2 <= para.length)
203           lm = new GridLayout( para[ 0 ], para[ 1 ] );
204         else
205           lm = new GridLayout();
206       } else if (s.equals( LayoutConverter.CARD_LAYOUT )) {
207         //
208         //  CARD_LAYOUT
209         //
210         //
211         int[] para = Util.ia( st );
212         if (para.length < 2)
213           lm = new CardLayout();
214         else
215           lm = new CardLayout( para[ 0 ], para[ 1 ] );
216       } else if (s.equals( LayoutConverter.GRIDBAG_LAYOUT )) {
217         //
218         //  Gridbag Layouts have some public arrays, accept one but only one.
219         //    public double[]  rowWeights
220         //    public double[]  colWeights
221         //
222         lm = new GridBagLayout();
223 
224         if (st.hasMoreTokens()) {
225           try {
226             String   fieldname = st.nextToken();
227             Field   field = GridBagLayout.class.getField( fieldname );
228             if (field != null) {
229               Class   fieldtype = field.getType();
230 
231               if (int[].class.equals( fieldtype )) {
232                 field.set( lm, Util.ia( st ) );
233               } else if (double[].class.equals( fieldtype )) {
234                 field.set( lm, Util.da( st ) );
235               }
236 
237             }
238           } catch (NoSuchFieldException   e) {
239             if (SwingEngine.DEBUG_MODE)
240               System.err.println( e.getMessage() );
241           } catch (SecurityException   e) {
242             if (SwingEngine.DEBUG_MODE)
243               System.err.println( e.getMessage() );
244           } catch (IllegalArgumentException   e) {
245             if (SwingEngine.DEBUG_MODE)
246               System.err.println( e.getMessage() );
247           } catch (IllegalAccessException   e) {
248             if (SwingEngine.DEBUG_MODE)
249               System.err.println( e.getMessage() );
250           }
251         }
252       }
253     }
254     return lm;
255   }
256 
257 
258   /**
259    * A <code>Converters</code> conversTo method informs about the Class type the converter
260    * is returning when its <code>convert</code> method is called
261    * @return <code>Class</code> - the Class the converter is returning when its convert method is called
262    */
263   public Class   convertsTo() {
264     return TEMPLATE;
265   }
266 }
267
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