| /* BreakIterator.java -- Breaks text into elements |
| Copyright (C) 1998, 1999, 2001, 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.text; |
| |
| import java.util.Locale; |
| import java.util.MissingResourceException; |
| import java.util.ResourceBundle; |
| |
| /** |
| * This class iterates over text elements such as words, lines, sentences, |
| * and characters. It can only iterate over one of these text elements at |
| * a time. An instance of this class configured for the desired iteration |
| * type is created by calling one of the static factory methods, not |
| * by directly calling a constructor. |
| * |
| * The standard iterators created by the factory methods in this |
| * class will be valid upon creation. That is, their methods will |
| * not cause exceptions if called before you call setText(). |
| * |
| * @author Tom Tromey (tromey@cygnus.com) |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @date March 19, 1999 |
| */ |
| /* Written using "Java Class Libraries", 2nd edition, plus online |
| * API docs for JDK 1.2 beta from http://www.javasoft.com. |
| * Status: Believed complete and correct to 1.1. |
| */ |
| public abstract class BreakIterator implements Cloneable |
| { |
| /** |
| * This value is returned by the <code>next()</code> and |
| * <code>previous</code> in order to indicate that the end of the |
| * text has been reached. |
| */ |
| // The value was discovered by writing a test program. |
| public static final int DONE = -1; |
| |
| /** |
| * This method initializes a new instance of <code>BreakIterator</code>. |
| * This protected constructor is available to subclasses as a default |
| * no-arg superclass constructor. |
| */ |
| protected BreakIterator () |
| { |
| } |
| |
| /** |
| * Create a clone of this object. |
| */ |
| public Object clone () |
| { |
| try |
| { |
| return super.clone(); |
| } |
| catch (CloneNotSupportedException e) |
| { |
| return null; |
| } |
| } |
| |
| /** |
| * This method returns the index of the current text element boundary. |
| * |
| * @return The current text boundary. |
| */ |
| public abstract int current (); |
| |
| /** |
| * This method returns the first text element boundary in the text being |
| * iterated over. |
| * |
| * @return The first text boundary. |
| */ |
| public abstract int first (); |
| |
| /** |
| * This methdod returns the offset of the text element boundary following |
| * the specified offset. |
| * |
| * @param offset The text index from which to find the next text boundary. |
| * |
| * @param The next text boundary following the specified index. |
| */ |
| public abstract int following (int pos); |
| |
| /** |
| * This method returns a list of locales for which instances of |
| * <code>BreakIterator</code> are available. |
| * |
| * @return A list of available locales |
| */ |
| public static synchronized Locale[] getAvailableLocales () |
| { |
| Locale[] l = new Locale[1]; |
| l[0] = Locale.US; |
| return l; |
| } |
| |
| private static BreakIterator getInstance (String type, Locale loc) |
| { |
| String className; |
| try |
| { |
| ResourceBundle res |
| = ResourceBundle.getBundle("gnu.java.locale.LocaleInformation", |
| loc, ClassLoader.getSystemClassLoader()); |
| className = res.getString(type); |
| } |
| catch (MissingResourceException x) |
| { |
| return null; |
| } |
| try |
| { |
| Class k = Class.forName(className); |
| return (BreakIterator) k.newInstance(); |
| } |
| catch (ClassNotFoundException x1) |
| { |
| return null; |
| } |
| catch (InstantiationException x2) |
| { |
| return null; |
| } |
| catch (IllegalAccessException x3) |
| { |
| return null; |
| } |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over characters as defined in the default locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getCharacterInstance () |
| { |
| return getCharacterInstance (Locale.getDefault()); |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over characters as defined in the specified locale. If the |
| * desired locale is not available, the default locale is used. |
| * |
| * @param locale The desired locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getCharacterInstance (Locale loc) |
| { |
| BreakIterator r = getInstance ("CharacterIterator", loc); |
| if (r == null) |
| r = new gnu.java.text.CharacterBreakIterator (); |
| return r; |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over line breaks as defined in the default locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getLineInstance () |
| { |
| return getLineInstance (Locale.getDefault()); |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over line breaks as defined in the specified locale. If the |
| * desired locale is not available, the default locale is used. |
| * |
| * @param locale The desired locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getLineInstance (Locale loc) |
| { |
| BreakIterator r = getInstance ("LineIterator", loc); |
| if (r == null) |
| r = new gnu.java.text.LineBreakIterator (); |
| return r; |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over sentences as defined in the default locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getSentenceInstance () |
| { |
| return getSentenceInstance (Locale.getDefault()); |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over sentences as defined in the specified locale. If the |
| * desired locale is not available, the default locale is used. |
| * |
| * @param locale The desired locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getSentenceInstance (Locale loc) |
| { |
| BreakIterator r = getInstance ("SentenceIterator", loc); |
| if (r == null) |
| r = new gnu.java.text.SentenceBreakIterator (); |
| return r; |
| } |
| |
| /** |
| * This method returns the text this object is iterating over as a |
| * <code>CharacterIterator</code>. |
| * |
| * @param The text being iterated over. |
| */ |
| public abstract CharacterIterator getText (); |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over words as defined in the default locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getWordInstance () |
| { |
| return getWordInstance (Locale.getDefault()); |
| } |
| |
| /** |
| * This method returns an instance of <code>BreakIterator</code> that will |
| * iterate over words as defined in the specified locale. If the |
| * desired locale is not available, the default locale is used. |
| * |
| * @param locale The desired locale. |
| * |
| * @return A <code>BreakIterator</code> instance for the default locale. |
| */ |
| public static BreakIterator getWordInstance (Locale loc) |
| { |
| BreakIterator r = getInstance ("WordIterator", loc); |
| if (r == null) |
| r = new gnu.java.text.WordBreakIterator (); |
| return r; |
| } |
| |
| /** |
| * This method tests whether or not the specified position is a text |
| * element boundary. |
| * |
| * @param offset The text position to test. |
| * |
| * @return <code>true</code> if the position is a boundary, |
| * <code>false</code> otherwise. |
| */ |
| public boolean isBoundary (int pos) |
| { |
| if (pos == 0) |
| return true; |
| return following (pos - 1) == pos; |
| } |
| |
| /** |
| * This method returns the last text element boundary in the text being |
| * iterated over. |
| * |
| * @return The last text boundary. |
| */ |
| public abstract int last (); |
| |
| /** |
| * This method returns the text element boundary following the current |
| * text position. |
| * |
| * @return The next text boundary. |
| */ |
| public abstract int next (); |
| |
| /** |
| * This method returns the n'th text element boundary following the current |
| * text position. |
| * |
| * @param n The number of text element boundaries to skip. |
| * |
| * @return The next text boundary. |
| */ |
| public abstract int next (int n); |
| |
| /** |
| * This methdod returns the offset of the text element boundary preceding |
| * the specified offset. |
| * |
| * @param offset The text index from which to find the preceding |
| * text boundary. |
| * |
| * @returns The next text boundary preceding the specified index. |
| */ |
| public int preceding (int pos) |
| { |
| if (following (pos) == DONE) |
| last (); |
| while (previous () >= pos) |
| ; |
| return current (); |
| } |
| |
| /** |
| * This method returns the text element boundary preceding the current |
| * text position. |
| * |
| * @return The previous text boundary. |
| */ |
| public abstract int previous (); |
| |
| /** |
| * This method sets the text string to iterate over. |
| * |
| * @param str The <code>String</code> to iterate over. |
| */ |
| public void setText (String newText) |
| { |
| setText (new StringCharacterIterator (newText)); |
| } |
| |
| /** |
| * This method sets the text to iterate over from the specified |
| * <code>CharacterIterator</code>. |
| * |
| * @param ci The desired <code>CharacterIterator</code>. |
| */ |
| public abstract void setText (CharacterIterator newText); |
| } |