Class DocumentFilter
- java.lang.Object
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- javax.swing.text.DocumentFilter
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public class DocumentFilter extends Object
DocumentFilter, as the name implies, is a filter for theDocumentmutation methods. When aDocumentcontaining aDocumentFilteris modified (either throughinsertorremove), it forwards the appropriate method invocation to theDocumentFilter. 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 inFilterBypass. Subclasses should NOT call back into the Document for the modification instead call into the superclass or theFilterBypass.When
removeorinsertStringis invoked on theDocumentFilter, theDocumentFiltermay callback into theFilterBypassmultiple times, or for different regions, but it should not callback into theFilterBypassafter returning from theremoveorinsertStringmethod.By default, text related document mutation methods such as
insertString,replaceandremoveinAbstractDocumentuseDocumentFilterwhen available, andElementrelated mutation methods such ascreate,insertandremoveElementinDefaultStyledDocumentdo not useDocumentFilter. 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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Document,AbstractDocument,DefaultStyledDocument
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Nested Class Summary
Nested Classes Modifier and Type Class and Description static classDocumentFilter.FilterBypassUsed as a way to circumvent calling back into the Document to change it.
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Constructor Summary
Constructors Constructor and Description DocumentFilter()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description voidinsertString(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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Method Detail
remove
public 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:
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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:
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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.
insertString
public 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:
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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:
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BadLocationException- the given insert position is not a valid position within the document
replace
public 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:
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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:
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BadLocationException- the given insert position is not a valid position within the document
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