001    /* AccessibleHyperlink.java -- aids in accessibly navigating hypertext
002       Copyright (C) 2002, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.accessibility;
040    
041    /**
042     * This object encapsulates actions associated with navigating hypertext.
043     *
044     * @author Eric Blake (ebb9@email.byu.edu)
045     * @see Accessible
046     * @see AccessibleContext
047     * @see AccessibleText
048     * @see AccessibleContext#getAccessibleText()
049     * @since 1.2
050     * @status updated to 1.4
051     */
052    public abstract class AccessibleHyperlink implements AccessibleAction
053    {
054      /**
055       * The default constructor.
056       */
057      public AccessibleHyperlink()
058      {
059      }
060    
061      /**
062       * Returns whether the document the link references is still valid, as the
063       * association may have changed with a text edit.
064       *
065       * @return true if the link is valid with respect to the AccessibleHypertext
066       */
067      public abstract boolean isValid();
068    
069      /**
070       * Get the number possible actions for this object, starting from 0. In
071       * general, a hypertext link has only one action, except for an image map,
072       * so there isn't really a default action.
073       *
074       * @return the 0-based number of actions
075       */
076      public abstract int getAccessibleActionCount();
077    
078      /**
079       * Perform the specified action. Does nothing if out of bounds.
080       *
081       * @param i the action to perform, 0-based
082       * @return true if the action was performed
083       * @see #getAccessibleActionCount()
084       */
085      public abstract boolean doAccessibleAction(int i);
086    
087      /**
088       * Get the anchor text of the link, or null if the index is out of bounds.
089       * For example, <a href="http://www.gnu.org/">GNU Home Page</a>
090       * would return "GNU Home Page", while <a HREF="#top">
091       * <img src="top-hat.png" alt="top hat"></a> would return
092       * "top hat".
093       *
094       * @param i the link to retrieve, 0-based
095       * @return the link anchor text
096       * @see #getAccessibleActionCount()
097       */
098      public abstract String getAccessibleActionDescription(int i);
099    
100      /**
101       * Get the link location, or null if the index is out of bounds. For
102       * example, <a href="http://www.gnu.org/">GNU Home Page</a>
103       * would return a java.net.URL("http://www.gnu.org/").
104       *
105       * @param i the link to retrieve, 0-based
106       * @return the link location
107       * @see #getAccessibleActionCount()
108       */
109      public abstract Object getAccessibleActionObject(int i);
110    
111      /**
112       * Get the anchor appropriate for the link, or null if the index is out of
113       * bounds. For example, <a href="http://www.gnu.org/">GNU Home Page
114       * </a> would return "GNU Home Page", while <a HREF="#top">
115       * <img src="top-hat.png" alt="top hat"></a> would return
116       * an ImageIcon("top-hat.png", "top hat").
117       *
118       * @param i the link to retrieve, 0-based
119       * @return the link anchor object
120       * @see #getAccessibleActionCount()
121       */
122      public abstract Object getAccessibleActionAnchor(int i);
123    
124      /**
125       * Gets the character index where this link starts in the parent hypertext
126       * document.
127       *
128       * @return the starting index
129       */
130      public abstract int getStartIndex();
131    
132      /**
133       * Gets the character index where this link ends in the parent hypertext
134       * document.
135       *
136       * @return the ending index
137       */
138      public abstract int getEndIndex();
139    } // class AccessibleAction