001/* AttributeSet.java -- 
002   Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package javax.swing.text;
039
040import java.util.Enumeration;
041
042/**
043 * A set of attributes. An attribute has a key and a value. They typically
044 * describe features of a piece of text that make up its graphical
045 * representation.
046 *
047 * An <code>AttributeSet</code> may have a resolving parent,
048 * that is another <code>AttributeSet</code> that is searched for attribute
049 * keys that are not stored locally in this <code>AttributeSet</code>.
050 *
051 * @author original author unknown
052 * @author Roman Kennke (roman@kennke.org)
053 */
054public interface AttributeSet
055{ 
056  /**
057   * Used as keys to identify character-run attributes.
058   */
059  static interface CharacterAttribute
060  {
061    // This interface is a marker interface and has no methods.
062  }
063
064  /**
065   * Used as keys to identify color attributes.
066   */
067  static interface ColorAttribute
068  {
069    // This interface is a marker interface and has no methods.
070  }
071
072  /**
073   * Used as keys to identify font attributes.
074   */
075  static interface FontAttribute
076  {
077    // This interface is a marker interface and has no methods.
078  }
079
080  /**
081   * Used as keys to identify paragraph level attributes.
082   */
083  static interface ParagraphAttribute
084  {
085    // This interface is a marker interface and has no methods.
086  }
087
088  /**
089   * Key of the attribute that is used to describe the name of an
090   * <code>AttributeSet</code>.
091   */
092  Object NameAttribute = StyleConstants.NameAttribute;
093
094  /**
095   * Key of the attribute that is used to identify the resolving parent of
096   * an <code>AttributeSet</code>.
097   */
098  Object ResolveAttribute = StyleConstants.ResolveAttribute;
099
100  /**
101   * Returns <code>true</code> if this <code>AttributeSet</code> contains
102   * an attribute with the specified <code>name</code> and <code>value</code>,
103   * <code>false</code> otherwise.
104   *
105   * @param name the name of the requested attribute
106   * @param value the value of the requested attribute
107   *
108   * @return <code>true</code> if this <code>AttributeSet</code> contains
109   *         an attribute with the specified <code>name</code> and
110   *         <code>value</code>, <code>false</code> otherwise
111   */
112  boolean containsAttribute(Object name, Object value);
113
114  /**
115   * Returns <code>true</code> of this <code>AttributeSet</code> contains all
116   * of the specified <code>attributes</code>.
117   *
118   * @param attributes the requested attributes
119   *
120   * @return <code>true</code> of this <code>AttributeSet</code> contains all
121   *         of the specified <code>attributes</code>
122   */
123  boolean containsAttributes(AttributeSet attributes);
124
125  /**
126   * Creates and returns a copy of this <code>AttributeSet</code>.
127   *
128   * @return a copy of this <code>AttributeSet</code>
129   */
130  AttributeSet copyAttributes();
131
132  /**
133   * Returns the attribute with the specified <code>key</code> or
134   * <code>null</code> if no such attribute is defined in this
135   * <code>AttributeSet</code> and its resolving parents.
136   *
137   * @param key the key of the attribute that is looked up
138   *
139   * @return the attribute with the specified <code>key</code> or
140   *         <code>null</code> if no such attribute is defined in this
141   *         <code>AttributeSet</code> and its resolving parents
142   */
143  Object getAttribute(Object key);
144
145  /**
146   * Returns the number of attributes that are stored locally in this
147   * <code>AttributeSet</code>.
148   *
149   * @return the number of attributes that are stored locally in this
150   * <code>AttributeSet</code>
151   */
152  int getAttributeCount();
153
154  /**
155   * Returns the names of the attributes that are stored in this
156   * <code>AttributeSet</code>.
157   *
158   * @return the names of the attributes that are stored in this
159   *         <code>AttributeSet</code>
160   */
161  Enumeration<?> getAttributeNames();
162
163  /**
164   * Returns the resolving parent of this <code>AttributeSet</code>.
165   * If a key is not stored locally, then a {@link #getAttribute(Object)}
166   * request is resolved up in the resolving parent of this
167   * <code>AttributeSet</code>.
168   *
169   * @return the resolving parent of this <code>AttributeSet</code>
170   */
171  AttributeSet getResolveParent();
172
173  /**
174   * Returns <code>true</code> if an attribute with the specified name is
175   * defined locally in this <code>AttributeSet</code>, without resolving
176   * through the resolving parents.
177   *
178   * @return <code>true</code> if an attribute with the specified name is
179   *          defined locally in this <code>AttributeSet</code>
180   */
181  boolean isDefined(Object attrName);
182
183  /**
184   * Returns <code>true</code> if all of the attributes in <code>attr</code>
185   * are equal to the attributes in this <code>AttributeSet</code>,
186   * <code>false</code> otherwise.
187   *
188   * @param attr the attributes to be compared to <code>this</code>
189   *
190   * @return <code>true</code> if all of the attributes in <code>attr</code>
191   *         are equal to the attributes in this <code>AttributeSet</code>,
192   *         <code>false</code> otherwise
193   */
194  boolean isEqual(AttributeSet attr);     
195}