Class DocumentFilter
java.lang.Object
javax.swing.text.DocumentFilter
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.
 
 By default, text related document mutation methods such as
 insertString, replace and remove
 in AbstractDocument use DocumentFilter when
 available, and Element related mutation methods such as
 create, insert and removeElement in
 DefaultStyledDocument do not use DocumentFilter.
 If a method doesn't follow these defaults, this must be explicitly stated
 in the method documentation.
- Since:
- 1.4
- See Also:
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Nested Class SummaryNested ClassesModifier and TypeClassDescriptionstatic classUsed as a way to circumvent calling back into the Document to change it.
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidinsertString(DocumentFilter.FilterBypass fb, int offset, String string, AttributeSet attr) Invoked prior to insertion of text into the specified Document.voidremove(DocumentFilter.FilterBypass fb, int offset, int length) Invoked prior to removal of the specified region in the specified Document.voidreplace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs) Invoked prior to replacing a region of text in the specified Document.
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Constructor Details- 
DocumentFilterpublic DocumentFilter()Constructs aDocumentFilter.
 
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Method Details- 
removepublic void remove(DocumentFilter.FilterBypass fb, int offset, int length) throws BadLocationException 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 theFilterBypassas 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.
 
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insertStringpublic void insertString(DocumentFilter.FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException 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
 
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replacepublic void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException 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
 
 
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