[cp-patches] FYI: Utilities fixes and additions

[Robert Schuster]

Hi,
this patch adds a helper method which I need for the TextAction instances in
DefaultEditorKit which I am currently rewriting (in other words the code is not
used yet).

More important are the small fixes to getWordStart and getPreviousWord. I found
out that the RI gives other return values and accepts a bigger range of input
offsets. The patch fixes that. Still these method have problems when numbers are
embedded into the text. I post a PR about this later.

2006-05-13  Robert Schuster  <[EMAIL PROTECTED]>

        * javax/swing/text/Utilities.java:
        (getNextWord): Fixed grammar in exception message.
        (getPreviousWord): Changed expression in first if-clause, added sub-
        expression to if-clause in while-loop.
        (getWordStart): Changed expression in if-clause.
        getNextVisualPositionFrom): Added package-private helper method.

cya
Robert

Index: javax/swing/text/Utilities.java
===================================================================
RCS file: /cvsroot/classpath/classpath/javax/swing/text/Utilities.java,v
retrieving revision 1.32
diff -u -r1.32 Utilities.java
--- javax/swing/text/Utilities.java	28 Apr 2006 09:44:08 -0000	1.32
+++ javax/swing/text/Utilities.java	13 May 2006 11:25:46 -0000
@@ -43,6 +43,9 @@
 import java.awt.Point;
 import java.text.BreakIterator;
 
+import javax.swing.SwingConstants;
+import javax.swing.text.Position.Bias;
+
 /**
  * A set of utilities to deal with text. This is used by several other classes
  * inside this package.
@@ -337,7 +340,7 @@
             // location or is not whitespace (meaning it is a number or
             // punctuation). The first case means that 'last' denotes the
             // beginning of a word while the second case means it is the start
-            // of some else.
+            // of something else.
             if (Character.isLetter(cp)
                 || !Character.isWhitespace(cp))
               return last;
@@ -346,7 +349,7 @@
         current = wb.next();
       }
     
-    throw new BadLocationException("no more word", offs);
+    throw new BadLocationException("no more words", offs);
   }
 
   /**
@@ -363,24 +366,36 @@
   public static final int getPreviousWord(JTextComponent c, int offs)
       throws BadLocationException
   {
-    if (offs < 0 || offs > (c.getText().length() - 1))
-      throw new BadLocationException("invalid offset specified", offs);
     String text = c.getText();
+    
+    if (offs <= 0 || offs > text.length())
+      throw new BadLocationException("invalid offset specified", offs);
+    
     BreakIterator wb = BreakIterator.getWordInstance();
     wb.setText(text);
     int last = wb.preceding(offs);
     int current = wb.previous();
+    int cp;
 
     while (current != BreakIterator.DONE)
       {
         for (int i = last; i < offs; i++)
           {
-            if (Character.isLetter(text.codePointAt(i)))
+            cp = text.codePointAt(i);
+            
+            // Return the last found bound if there is a letter at the current
+            // location or is not whitespace (meaning it is a number or
+            // punctuation). The first case means that 'last' denotes the
+            // beginning of a word while the second case means it is the start
+            // of some else.
+            if (Character.isLetter(cp)
+                || !Character.isWhitespace(cp))
               return last;
           }
         last = current;
         current = wb.previous();
       }
+    
     return 0;
   }
   
@@ -394,14 +409,17 @@
   public static final int getWordStart(JTextComponent c, int offs)
       throws BadLocationException
   {
-    if (offs < 0 || offs >= c.getText().length())
+    String text = c.getText();
+    
+    if (offs < 0 || offs > text.length())
       throw new BadLocationException("invalid offset specified", offs);
     
-    String text = c.getText();
     BreakIterator wb = BreakIterator.getWordInstance();
     wb.setText(text);
+
     if (wb.isBoundary(offs))
       return offs;
+
     return wb.preceding(offs);
   }
   
@@ -674,4 +692,38 @@
     else
       return offs+1;
     }
+  
+  /** This is an internal helper method which is used by the
+   * <code>javax.swing.text</code> package. It simply delegates the
+   * call to a method with the same name on the <code>NavigationFilter</code>
+   * of the provided <code>JTextComponent</code> (if it has one) or its UI.
+   * 
+   * If the underlying method throws a <code>BadLocationException</code> it
+   * will be swallowed and the initial offset is returned.
+   */
+  static int getNextVisualPositionFrom(JTextComponent t, int offset, int direction)
+  {
+    NavigationFilter nf = t.getNavigationFilter();
+    
+    try
+      {
+        return (nf != null) 
+          ? nf.getNextVisualPositionFrom(t,
+                                         offset,
+                                         Bias.Forward,
+                                         direction,
+                                         null)
+          : t.getUI().getNextVisualPositionFrom(t,
+                                                offset,
+                                                Bias.Forward,
+                                                direction,
+                                                null);
+      }
+    catch (BadLocationException ble)
+    {
+      return offset;
+    }
+    
+  }
+  
 }

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