Source for gnu.javax.swing.text.html.CombinedAttributes

   1: /* CombinedAttributes.java -- A two combined sets of attributes
   2:    Copyright (C) 2006 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.javax.swing.text.html;
  40: 
  41: import java.io.Serializable;
  42: import java.util.Enumeration;
  43: 
  44: import javax.swing.text.AttributeSet;
  45: import javax.swing.text.SimpleAttributeSet;
  46: 
  47: /**
  48:  * Contains the two combined attribute sets what are searched subsequently.
  49:  * This is used to combine style sheet attributes with the HTML view attributes.
  50:  * The parent cannot be used as the view may have its own attribute hierarchy.
  51:  *
  52:  * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
  53:  */
  54: public class CombinedAttributes implements AttributeSet, Serializable
  55: {
  56:   /**
  57:    * Returns the elements from both enumerations.
  58:    */
  59:   class CombinedEnumeration implements Enumeration
  60:   {
  61:     /**
  62:      * Create a combined enumeration that enumerates over two enumerations.
  63:      *
  64:      * @param first the first enumeration to enumerate
  65:      * @param second the second enumeration to enumerate
  66:      */
  67:     CombinedEnumeration(Enumeration first, Enumeration second)
  68:     {
  69:       a = first;
  70:       b = second;
  71:     }
  72: 
  73:     /**
  74:      * The first enumeration (elements returned first)
  75:      */
  76:     final Enumeration a;
  77: 
  78:     /**
  79:      * The second enumeration (elements returned later)
  80:      */
  81:     final Enumeration b;
  82: 
  83:     /** @inheritDoc */
  84:     public boolean hasMoreElements()
  85:     {
  86:       return a.hasMoreElements() || b.hasMoreElements();
  87:     }
  88: 
  89:     /** @inheritDoc */
  90:     public Object nextElement()
  91:     {
  92:       return a.hasMoreElements() ? a.nextElement():b.nextElement();
  93:     }
  94:   }
  95: 
  96: 
  97:   /**
  98:    * The first attribute set.
  99:    */
 100:   final AttributeSet a;
 101: 
 102:   /**
 103:    * The second attribute set.
 104:    */
 105:   final AttributeSet b;
 106: 
 107:   /**
 108:    * Create the CombinedAttributes what search in the two sets. If any of the
 109:    * two passed sets is null, another set is returned. Otherwise, the combined
 110:    * attribute set is returned.
 111:    *
 112:    * @param primary the first set (searched first)
 113:    * @param secondary the second set (searched later).
 114:    */
 115:   public static AttributeSet combine(AttributeSet primary,
 116:                                      AttributeSet secondary)
 117:   {
 118:     if (primary == null)
 119:       return secondary;
 120:     else if (secondary == null)
 121:       return primary;
 122:     else
 123:       return new CombinedAttributes(primary, secondary);
 124:   }
 125: 
 126:   /**
 127:    * Create the CombinedAttributes what search in the two sets.
 128:    *
 129:    * @param primary the first set (searched first)
 130:    * @param secondary the second set (searched later).
 131:    */
 132:   private CombinedAttributes(AttributeSet primary, AttributeSet secondary)
 133:   {
 134:     a = primary;
 135:     b = secondary;
 136:   }
 137: 
 138:   /** @inheritDoc */
 139:   public boolean containsAttribute(Object name, Object value)
 140:   {
 141:     return a.containsAttribute(name, value) || b.containsAttribute(name, value);
 142:   }
 143: 
 144:   /** @inheritDoc */
 145:   public boolean containsAttributes(AttributeSet attributes)
 146:   {
 147:     Enumeration names = attributes.getAttributeNames();
 148:     Object name;
 149:     while (names.hasMoreElements())
 150:       {
 151:         name = names.nextElement();
 152:         if (!containsAttribute(name, attributes.getAttribute(name)))
 153:           return false;
 154:       }
 155:     return true;
 156:   }
 157: 
 158:   /** @inheritDoc */
 159:   public AttributeSet copyAttributes()
 160:   {
 161:     SimpleAttributeSet copy = new SimpleAttributeSet();
 162:     copy.addAttributes(a);
 163:     copy.addAttributes(b);
 164:     return copy;
 165:   }
 166: 
 167:   /** @inheritDoc */
 168:   public Object getAttribute(Object key)
 169:   {
 170:     Object value = a.getAttribute(key);
 171:     if (value == null)
 172:       value = b.getAttribute(key);
 173: 
 174:     return value;
 175:   }
 176: 
 177:   /** @inheritDoc */
 178:   public int getAttributeCount()
 179:   {
 180:     return a.getAttributeCount()+b.getAttributeCount();
 181:   }
 182: 
 183:   /** @inheritDoc */
 184:   public Enumeration getAttributeNames()
 185:   {
 186:     return new CombinedEnumeration(a.getAttributeNames(), b.getAttributeNames());
 187:   }
 188: 
 189:   /**
 190:    * There is no one.
 191:    *
 192:    * @return null, always.
 193:    */
 194:   public AttributeSet getResolveParent()
 195:   {
 196:     return null;
 197:   }
 198: 
 199:   /** @inheritDoc */
 200:   public boolean isDefined(Object attrName)
 201:   {
 202:     return a.isDefined(attrName) || b.isDefined(attrName);
 203:   }
 204: 
 205:   /** @inheritDoc */
 206:   public boolean isEqual(AttributeSet attr)
 207:   {
 208:     if (attr.getAttributeCount() == getAttributeCount())
 209:       return containsAttributes(attr);
 210:     else
 211:       return false;
 212:   }
 213: }