1 files changed, 48 insertions, 11 deletions

diff --git a/javax/swing/text/AbstractDocument.java b/javax/swing/text/AbstractDocument.java
index bb065044d..801a0cdb4 100644
--- a/javax/swing/text/AbstractDocument.java
+++ b/javax/swing/text/AbstractDocument.java
@@ -543,6 +543,10 @@ public abstract class AbstractDocument implements Document, Serializable
    * 
    * <p>If a {@link DocumentFilter} is installed in this document, the
    * corresponding method of the filter object is called.</p>
+   * 
+   * <p>The method has no effect when <code>text</code> is <code>null</code>
+   * or has a length of zero.</p>
+   * 
    *
    * @param offset the location at which the string should be inserted
    * @param text the content to be inserted
@@ -554,10 +558,14 @@ public abstract class AbstractDocument implements Document, Serializable
   public void insertString(int offset, String text, AttributeSet attributes)
     throws BadLocationException
   {
-    if (documentFilter != null)
-      documentFilter.insertString(getBypass(), offset, text, attributes);
-    else
+    // Bail out if we have a bogus insertion (Behavior observed in RI).
+    if (text == null || text.length() == 0)
+      return;
+    
+    if (documentFilter == null)
       insertStringImpl(offset, text, attributes);
+    else
+      documentFilter.insertString(getBypass(), offset, text, attributes);
   }
 
   void insertStringImpl(int offset, String text, AttributeSet attributes)
@@ -706,8 +714,14 @@ public abstract class AbstractDocument implements Document, Serializable
    * Removes a piece of content from this <code>Document</code>.
    * 
    * <p>If a {@link DocumentFilter} is installed in this document, the
-   * corresponding method of the filter object is called.</p>
-   *
+   * corresponding method of the filter object is called. The
+   * <code>DocumentFilter</code> is called even if <code>length</code>
+   * is zero. This is different from {@link #replace}.</p>
+   * 
+   * <p>Note: When <code>length</code> is zero or below the call is not
+   * forwarded to the underlying {@link AbstractDocument.Content} instance
+   * of this document and no exception is thrown.</p>
+   * 
    * @param offset the start offset of the fragment to be removed
    * @param length the length of the fragment to be removed
    *
@@ -717,14 +731,18 @@ public abstract class AbstractDocument implements Document, Serializable
    */
   public void remove(int offset, int length) throws BadLocationException
   {
-    if (documentFilter != null)
-      documentFilter.remove(getBypass(), offset, length);
-    else
+    if (documentFilter == null)
       removeImpl(offset, length);
+    else
+      documentFilter.remove(getBypass(), offset, length);
   }
   
   void removeImpl(int offset, int length) throws BadLocationException
   {
+    // Prevent some unneccessary method invocation (observed in the RI). 
+    if (length <= 0)
+      return;
+    
     DefaultDocumentEvent event =
       new DefaultDocumentEvent(offset, length,
 			       DocumentEvent.EventType.REMOVE);
@@ -752,6 +770,10 @@ public abstract class AbstractDocument implements Document, Serializable
    * 
    * <p>If a {@link DocumentFilter} is installed in this document, the
    * corresponding method of the filter object is called.</p>
+   * 
+   * <p>The method has no effect if <code>length</code> is zero (and
+   * only zero) and, at the same time, <code>text</code> is
+   * <code>null</code> or has zero length.</p>
    *
    * @param offset the start offset of the fragment to be removed
    * @param length the length of the fragment to be removed
@@ -768,10 +790,25 @@ public abstract class AbstractDocument implements Document, Serializable
                       AttributeSet attributes)
     throws BadLocationException
   {
-    if (documentFilter != null)
-      documentFilter.replace(getBypass(), offset, length, text, attributes);
+    // Bail out if we have a bogus replacement (Behavior observed in RI).
+    if (length == 0 
+        && (text == null || text.length() == 0))
+      return;
+    
+    if (documentFilter == null)
+      {
+        // It is important to call the methods which again do the checks
+        // of the arguments and the DocumentFilter because subclasses may
+        // have overridden these methods and provide crucial behavior
+        // which would be skipped if we call the non-checking variants.
+        // An example for this is PlainDocument where insertString can
+        // provide a filtering of newlines.
+        remove(offset, length);
+        insertString(offset, text, attributes);
+      }
     else
-      replaceImpl(offset, length, text, attributes);
+      documentFilter.replace(getBypass(), offset, length, text, attributes);
+    
   }
   
   void replaceImpl(int offset, int length, String text,