public class

DocumentFilter

extends Object
java.lang.Object
   ↳ javax.swing.text.DocumentFilter

Class Overview

DocumentFilter, as the name implies, is a filter for the Document mutation methods. When a Document containing a DocumentFilter is modified (either through insert or remove), it forwards the appropriate method invocation to the DocumentFilter. The default implementation allows the modification to occur. Subclasses can filter the modifications by conditionally invoking methods on the superclass, or invoking the necessary methods on the passed in FilterBypass. Subclasses should NOT call back into the Document for the modification instead call into the superclass or the FilterBypass.

When remove or insertString is invoked on the DocumentFilter, the DocumentFilter may callback into the FilterBypass multiple times, or for different regions, but it should not callback into the FilterBypass after returning from the remove or insertString method.

See Also

Summary

Nested Classes
class DocumentFilter.FilterBypass Used as a way to circumvent calling back into the Document to change it. 
Public Constructors
DocumentFilter()
Public Methods
void insertString(DocumentFilter.FilterBypass fb, int offset, String string, AttributeSet attr)
Invoked prior to insertion of text into the specified Document.
void remove(DocumentFilter.FilterBypass fb, int offset, int length)
Invoked prior to removal of the specified region in the specified Document.
void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
Invoked prior to replacing a region of text in the specified Document.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public DocumentFilter ()

Public Methods

public void insertString (DocumentFilter.FilterBypass fb, int offset, String string, AttributeSet attr)

Invoked prior to insertion of text into the specified Document. Subclasses that want to conditionally allow insertion should override this and only call supers implementation as necessary, or call directly into the FilterBypass.

Parameters
fb FilterBypass that can be used to mutate Document
offset the offset into the document to insert the content >= 0. All positions that track change at or after the given location will move.
string the string to insert
attr the attributes to associate with the inserted content. This may be null if there are no attributes.
Throws
BadLocationException the given insert position is not a valid position within the document

public void remove (DocumentFilter.FilterBypass fb, int offset, int length)

Invoked prior to removal of the specified region in the specified Document. Subclasses that want to conditionally allow removal should override this and only call supers implementation as necessary, or call directly into the FilterBypass as necessary.

Parameters
fb FilterBypass that can be used to mutate Document
offset the offset from the beginning >= 0
length the number of characters to remove >= 0
Throws
BadLocationException some portion of the removal range was not a valid part of the document. The location in the exception is the first bad position encountered.

public void replace (DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs)

Invoked prior to replacing a region of text in the specified Document. Subclasses that want to conditionally allow replace should override this and only call supers implementation as necessary, or call directly into the FilterBypass.

Parameters
fb FilterBypass that can be used to mutate Document
offset Location in Document
length Length of text to delete
text Text to insert, null indicates no text to insert
attrs AttributeSet indicating attributes of inserted text, null is legal.
Throws
BadLocationException the given insert position is not a valid position within the document