javax.swing.text
Interface Document

All Known Subinterfaces:

StyledDocument

All Known Implementing Classes:

AbstractDocument

public abstract interface Document

Container for text that supports editing and provides notification of changes (serves as the model in an MVC relationship). Support is provided to mark up the text with structure that tracks changes. The unit of structure is called an element. Views will typically be built from an element structure. Each element can have an arbitrary set of attributes associated with it. The interface itself is intended to be free of any policy for structure that is provided, as the nature of the document structure should be determined by the implementation.

Typically there will be only one document structure, but the interface supports building an arbitrary number of structural projections over the text data. The document can have multiple root elements to support multiple document structures. Some examples might be:

• Logical document structure.
• View projections.
• Lexical token streams.
• Parse trees.
• Conversions to formats other than the native format.
• Modification specifications.
• Annotations.

See Also:

DocumentEvent, DocumentListener, Element, Position, AttributeSet

Field Summary

static String	StreamDescriptionProperty The property name for the description of the stream used to initialize the document.
static String	TitleProperty The property name for the title of the document, if there is one.

Method Summary

void	addDocumentListener(DocumentListener listener) Registers the given observer to begin receiving notifications when changes are made to the document.
void	addUndoableEditListener(UndoableEditListener listener) Registers the given observer to begin receiving notifications when undoable edits are made to the document.
Position	createPosition(int offs) Returns a position that will track change as the document is altered.
Element	getDefaultRootElement() Returns the root element that views should be based upon, unless some other mechanism for assigning views to element structures is provided.
Position	getEndPosition() Returns a position that represents the end of the document.
int	getLength() Returns number of characters of content currently in the document.
Object	getProperty(Object key) Gets properties associated with the document.
Element[]	getRootElements() Returns all of the root elements that are defined.
Position	getStartPosition() Returns a position that represents the start of the document.
String	getText(int offset, int length) Fetches the text contained within the given portion of the document.
void	getText(int offset, int length, Segment txt) Fetches the text contained within the given portion of the document.
void	insertString(int offset, String str, AttributeSet a) Inserts a string of content.
void	putProperty(Object key, Object value) Puts a new property on the list.
void	remove(int offs, int len) Removes a portion of the content of the document.
void	removeDocumentListener(DocumentListener listener) Unregisters the given observer from the notification list so it will no longer receive change updates.
void	removeUndoableEditListener(UndoableEditListener listener) Unregisters the given observer from the notification list so it will no longer receive updates.
void	render(Runnable r) This allows the model to be safely rendered in the presence of currency, if the model supports being updated asynchronously.

Field Detail

StreamDescriptionProperty

public static final String StreamDescriptionProperty

The property name for the description of the stream used to initialize the document. This should be used if the document was initialized from a stream and anything is known about the stream.

TitleProperty

public static final String TitleProperty

The property name for the title of the document, if there is one.

Method Detail

getLength

public int getLength()

Returns number of characters of content currently in the document.

Returns:

number of characters >= 0

addDocumentListener

public void addDocumentListener(DocumentListener listener)

Registers the given observer to begin receiving notifications when changes are made to the document.

Parameters:

listener - the observer to register

See Also:

removeDocumentListener(javax.swing.event.DocumentListener)

removeDocumentListener

public void removeDocumentListener(DocumentListener listener)

Unregisters the given observer from the notification list so it will no longer receive change updates.

Parameters:

listener - the observer to register

See Also:

addDocumentListener(javax.swing.event.DocumentListener)

addUndoableEditListener

public void addUndoableEditListener(UndoableEditListener listener)

Registers the given observer to begin receiving notifications when undoable edits are made to the document.

Parameters:

listener - the observer to register

See Also:

UndoableEditEvent

removeUndoableEditListener

public void removeUndoableEditListener(UndoableEditListener listener)

Unregisters the given observer from the notification list so it will no longer receive updates.

Parameters:

listener - the observer to register

See Also:

UndoableEditEvent

getProperty

public Object getProperty(Object key)

Gets properties associated with the document. Allows one to store things like the document title, author, etc.

Parameters:

key - a non-null property

Returns:

the properties

putProperty

public void putProperty(Object key,
                        Object value)

Puts a new property on the list.

Parameters:

key - the non-null property key

value - the property value

remove

public void remove(int offs,
                   int len)
            throws BadLocationException

Removes a portion of the content of the document. This will cause notification to be sent to the observers of the document (unless an exception is thrown).

Parameters:

offs - the offset from the begining >= 0

len - 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.

See Also:

DocumentEvent, DocumentListener

insertString

public void insertString(int offset,
                         String str,
                         AttributeSet a)
                  throws BadLocationException

Inserts a string of content. This will cause the observers of the the document to be notified, unless an exception is thrown. A position marks a location in the document between items. If the attributes that have been defined exactly match the current attributes defined at the position, the element representing the content at that position will simply be expanded. If the attributes defined are different, a new content element will be created that matches the attributes. Does nothing with null or empty strings.

Parameters:

offset - the offset into the document to insert the content >= 0. All positions that track change at or after the given location will move.

str - the string to insert

a - 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

See Also:

DocumentEvent, DocumentListener

getText

public String getText(int offset,
                      int length)
               throws BadLocationException

Fetches the text contained within the given portion of the document.

Parameters:

offset - the offset into the document representing the desired start of the text >= 0

length - the length of the desired string >= 0

Returns:

the text, in a String of length >= 0

Throws:

BadLocationException - some portion of the given range was not a valid part of the document. The location in the exception is the first bad position encountered.

getText

public void getText(int offset,
                    int length,
                    Segment txt)
             throws BadLocationException

Fetches the text contained within the given portion of the document.

Parameters:

offset - the offset into the document representing the desired start of the text >= 0

length - the length of the desired string >= 0

txt - the Segment object to return the text in

Throws:

BadLocationException - Some portion of the given range was not a valid part of the document. The location in the exception is the first bad position encountered.

getStartPosition

public Position getStartPosition()

Returns a position that represents the start of the document. The position returned can be counted on to track change and stay located at the beginning of the document.

Returns:

the position

getEndPosition

public Position getEndPosition()

Returns a position that represents the end of the document. The position returned can be counted on to track change and stay located at the end of the document.

Returns:

the position

createPosition

public Position createPosition(int offs)
                        throws BadLocationException

Returns a position that will track change as the document is altered. If the relative position pos is null, the start of the document will be used.

Parameters:

offs - the offset from the start of the document >= 0

Returns:

the position

Throws:

BadLocationException - if the given position does not represent a valid location in the associated document

getRootElements

public Element[] getRootElements()

Returns all of the root elements that are defined.

Returns:

the root element

getDefaultRootElement

public Element getDefaultRootElement()

Returns the root element that views should be based upon, unless some other mechanism for assigning views to element structures is provided.

Returns:

the root element

render

public void render(Runnable r)

This allows the model to be safely rendered in the presence of currency, if the model supports being updated asynchronously. The given runnable will be executed in a way that allows it to safely read the model with no changes while the runnable is being executed. The runnable itself may not make any mutations.

Parameters:

r - a Runnable used to render the model