CSSAttributeSet


1   /*
2    * $Id: CSSAttributeSet.java,v 1.1 2005/05/27 09:17:35 blueshift Exp $
3    * Copyright 2000,2005 wingS development team.
4    *
5    * This file is part of wingS (http://www.j-wings.org).
6    *
7    * wingS is free software; you can redistribute it and/or modify
8    * it under the terms of the GNU Lesser General Public License
9    * as published by the Free Software Foundation; either version 2.1
10   * of the License, or (at your option) any later version.
11   *
12   * Please see COPYING for the complete licence.
13   */
14  package org.wings.style;
15  
16  import org.wings.Renderable;
17  import org.wings.io.Device;
18  
19  import java.io.IOException  ;
20  import java.io.Serializable  ;
21  import java.util.*;
22  
23  /**
24   * A straightforward implementation of CSSPropertySet using a hash map.
25   *
26   * @author <a HREF="mailto:engels@mercatis.de">Holger Engels</a>
27   * @version $Revision: 1.1 $
28   */
29  public class CSSAttributeSet
30          implements Renderable, Serializable  , Cloneable   {
31      public static final CSSAttributeSet EMPTY_ATTRIBUTESET =
32              new CSSAttributeSet() {
33                  private UnsupportedOperationException    doThrow() {
34                      return new UnsupportedOperationException  ("cannot change values for the global EMPTY_ATTRIBUTESET. You attempted to modify this unmodifiable CSSPropertySet: create your own instance of a CSSPropertySet first!");
35                  }
36  
37                  public String   put(String   name, String   value) {
38                      throw doThrow();
39                  }
40  
41                  public boolean putAll(CSSAttributeSet attributes) {
42                      throw doThrow();
43                  }
44              };
45  
46      private Map map;
47  
48      /**
49       * create a CSSPropertySet from the given HashMap.
50       */
51      private CSSAttributeSet(HashMap map) {
52          this.map = map;
53      }
54  
55      /**
56       * Creates a new, empty atribute set.
57       */
58      public CSSAttributeSet() {
59      }
60  
61      public CSSAttributeSet(CSSProperty cssProperty, String   cssPropertyValue) {
62          put(cssProperty, cssPropertyValue);
63      }
64  
65      /**
66       * Creates a new attribute set based on a supplied set of attributes.
67       *
68       * @param source the set of attributes
69       */
70      public CSSAttributeSet(CSSAttributeSet source) {
71          putAll(source);
72      }
73  
74      /**
75       * Checks whether the set of attributes is empty.
76       *
77       * @return true if the set is empty else false
78       */
79      public final boolean isEmpty() {
80          return map == null || map.isEmpty();
81      }
82  
83      /**
84       * Gets a count of the number of attributes.
85       *
86       * @return the count
87       */
88      public final int size() {
89          return map == null ? 0 : map.size();
90      }
91  
92      public final void clear() {
93          if (map != null) {
94              map.clear();
95          }
96      }
97  
98      /**
99       * Tells whether a given attribute is defined.
100      *
101      * @param name the attribute name
102      * @return true if the attribute is defined
103      */
104     public final boolean contains(CSSProperty name) {
105         return map == null ? false : map.containsKey(name);
106     }
107 
108     /**
109      * Gets the defned CSS properties in the set.
110      *
111      * @return A set of {@link CSSProperty}
112      */
113     public final Set properties() {
114         return map == null ? Collections.EMPTY_SET : map.keySet();
115     }
116 
117     /**
118      * Gets the value of an css property.
119      *
120      * @param property the attribute property
121      * @return the value
122      */
123     public final String   get(CSSProperty property) {
124         return map == null ? null : (String  ) map.get(property);
125     }
126 
127     /**
128      * Adds an attribute to the list.
129      *
130      * @param name  the attribute name
131      * @param value the attribute value
132      */
133     public String   put(CSSProperty name, String   value) {
134         if (map == null) {
135             map = new HashMap(8);
136         }
137 
138         if (value == null)
139             return remove(name);
140         return (String  ) map.put(name, value);
141     }
142 
143     /**
144      * Adds a set of attributes to the list.
145      *
146      * @param attributes the set of attributes to add
147      */
148     public boolean putAll(CSSAttributeSet attributes) {
149         if (map == null) {
150             map = new HashMap(8);
151         }
152 
153         boolean changed = false;
154         Iterator names = attributes.properties().iterator();
155         while (names.hasNext()) {
156             CSSProperty property = (CSSProperty) names.next();
157             changed = changed || (put(property, attributes.get(property)) != null);
158         }
159         return changed;
160     }
161 
162     /**
163      * Removes an attribute from the list.
164      *
165      * @param name the attribute name
166      */
167     public String   remove(CSSProperty name) {
168         return map == null ? null : (String  ) map.remove(name);
169     }
170 
171     // --- Object methods ---------------------------------
172 
173     /**
174      * Clones a set of attributes.
175      *
176      * @return the new set of attributes
177      */
178     public Object   clone() {
179         /*
180         try {
181             attr = (CSSPropertySet)super.clone();
182             attr.putAll(this);
183         } catch (CloneNotSupportedException cnse) {
184             attr = null;
185         }
186         */
187 
188         if (isEmpty()) {
189             return new CSSAttributeSet();
190         } else {
191             return new CSSAttributeSet((HashMap) ((HashMap) map).clone());
192         }
193     }
194 
195     /**
196      * Returns a hashcode for this set of attributes.
197      *
198      * @return a hashcode value for this set of attributes.
199      */
200     public int hashCode() {
201         return map == null ? 0 : map.hashCode();
202     }
203 
204     /**
205      * Compares two attribute sets.
206      *
207      * @param object the second attribute set
208      * @return true if the sets are equal, false otherwise
209      */
210     public boolean equals(Object   object) {
211         if (!(object instanceof CSSAttributeSet))
212             return false;
213         CSSAttributeSet other = (CSSAttributeSet) object;
214 
215         if (size() != other.size())
216             return false;
217 
218         Iterator names = other.properties().iterator();
219         while (names.hasNext()) {
220             CSSProperty property = (CSSProperty) names.next();
221             if (!other.get(property).equals(get(property)))
222                 return false;
223         }
224         return true;
225     }
226 
227     /**
228      * Write style definition to the device. If include is true, write those
229      * contained in the {@link java.util.List}. If include is false, write those not contained
230      * in the {@link java.util.List}.
231      * Basically this is a filter on the styles, so we can separate styles for
232      * one logical component onto multiple real html elements.  
233      */
234     public void writeFiltered(Device d, List l, boolean include) throws IOException   {
235         if (l == null) l = Collections.EMPTY_LIST;
236         if (map != null) {
237             Iterator names = map.entrySet().iterator();
238             while (names.hasNext()) {
239                 Map.Entry next = (Map.Entry) names.next();
240                 if ( !(l.contains(next.getKey()) ^ include) ) {
241                     d.print(next.getKey()).print(":")
242                             .print(next.getValue())
243                             .print("; ");
244                 }
245             }
246         }
247     }
248     
249     /**
250      * Write style definition to the device. Write only those not contained
251      * in the set.
252      */
253     public void writeExcluding(Device d, List l) throws IOException   {
254         writeFiltered(d, l, false);
255     }
256 
257     /**
258      * Write style definition to the device. Write only those  contained
259      * in the set.
260      */
261     public void writeIncluding(Device d, List l) throws IOException   {
262         writeFiltered(d, l, true);
263     }
264 
265     /**
266      * Write style definition to the device
267      */
268     public void write(Device d)
269             throws IOException   {
270         if (map != null) {
271             Iterator names = map.entrySet().iterator();
272             while (names.hasNext()) {
273                 Map.Entry next = (Map.Entry) names.next();
274                 d.print(next.getKey()).print(":")
275                         .print(next.getValue())
276                         .print("; ");
277             }
278         }
279     }
280 
281     /**
282      * Converts the attribute set to a String.
283      *
284      * @return the string
285      */
286     public String   toString() {
287         StringBuffer   b = new StringBuffer  ();
288 
289         if (map != null) {
290             Iterator names = map.entrySet().iterator();
291             while (names.hasNext()) {
292                 Map.Entry next = (Map.Entry) names.next();
293                 b.append(next.getKey());
294                 b.append(":");
295                 b.append(next.getValue());
296                 b.append("; ");
297             }
298         }
299         return b.toString();
300     }
301 }
302 
303 
304
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