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JavaTM 2 Platform Std. Ed. v1.3 |
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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object | +--javax.swing.text.AbstractDocument
An implementation of the document interface to serve as a basis for implementing various kinds of documents. At this level there is very little policy, so there is a corresponding increase in difficulty of use.
This class implements a locking mechanism for the document. It
allows multiple readers or one writer, and writers must wait until
all observers of the document have been notified of a previous
change before beginning another mutation to the document. The
read lock is aquired and released using the render
method. A write lock is aquired by the methods that mutate the
document, and are held for the duration of the method call.
Notification is done on the thread that produced the mutation,
and the thread has full read access to the document for the
duration of the notification, but other readers are kept out
until the notification has finished. The notification is a
beans event notification which does not allow any further
mutations until all listeners have been notified.
Any models subclassed from this class and used in conjunction
with a text component that has a look and feel implementation
that is derived from BasicTextUI may be safely updated
asynchronously, because all access to the View hierarchy
is serialized by BasicTextUI if the document is of type
AbstractDocument
. The locking assumes that an
independant thread will access the View hierarchy only from
the DocumentListener methods, and that there will be only
one event thread active at a time.
If concurrency support is desired, there are the following
additional implications. The code path for any DocumentListener
implementation and any UndoListener implementation must be threadsafe,
and not access the component lock if trying to be safe from deadlocks.
The repaint
and revalidate
methods
on JComponent are safe.
AbstractDocument models an implied break at the end of the document.
Among other things this allows you to position the caret after the last
character. As a result of this, getLength
returns one less
than the length of the Content. If you create your own Content, be
sure and initialize it to have an additional character. Refer to
StringContent and GapContent for examples of this. Another implication
of this is that Elements that model the implied end character will have
an endOffset == (getLength() + 1). For example, in DefaultStyledDocument
getParagraphElement(getLength()).getEndOffset() == getLength() + 1
.
Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. A future release of Swing will provide support for long term persistence.
Inner Class Summary | |
class |
AbstractDocument.AbstractElement
Implements the abstract part of an element. |
static interface |
AbstractDocument.AttributeContext
An interface that can be used to allow MutableAttributeSet implementations to use pluggable attribute compression techniques. |
class |
AbstractDocument.BranchElement
Implements a composite element that contains other elements. |
static interface |
AbstractDocument.Content
Interface to describe a sequence of character content that can be edited. |
class |
AbstractDocument.DefaultDocumentEvent
Stores document changes as the document is being modified. |
static class |
AbstractDocument.ElementEdit
An implementation of ElementChange that can be added to the document event. |
class |
AbstractDocument.LeafElement
Implements an element that directly represents content of some kind. |
Field Summary | |
protected static String |
BAD_LOCATION
Error message to indicate a bad location. |
static String |
BidiElementName
Name of elements used to hold a unidirectional run |
static String |
ContentElementName
Name of elements used to represent content |
static String |
ElementNameAttribute
Name of the attribute used to specify element names. |
protected EventListenerList |
listenerList
The event listener list for the document. |
static String |
ParagraphElementName
Name of elements used to represent paragraphs |
static String |
SectionElementName
Name of elements used to hold sections (lines/paragraphs). |
Fields inherited from interface javax.swing.text.Document |
StreamDescriptionProperty, TitleProperty |
Constructor Summary | |
protected |
AbstractDocument(AbstractDocument.Content data)
Constructs a new AbstractDocument, wrapped around some specified content storage mechanism. |
protected |
AbstractDocument(AbstractDocument.Content data,
AbstractDocument.AttributeContext context)
Constructs a new AbstractDocument, wrapped around some specified content storage mechanism. |
Method Summary | |
void |
addDocumentListener(DocumentListener listener)
Adds a document listener for notification of any changes. |
void |
addUndoableEditListener(UndoableEditListener listener)
Adds an undo listener for notification of any changes. |
protected Element |
createBranchElement(Element parent,
AttributeSet a)
Creates a document branch element, that can contain other elements. |
protected Element |
createLeafElement(Element parent,
AttributeSet a,
int p0,
int p1)
Creates a document leaf element. |
Position |
createPosition(int offs)
Returns a position that will track change as the document is altered. |
void |
dump(PrintStream out)
Gives a diagnostic dump. |
protected void |
fireChangedUpdate(DocumentEvent e)
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
fireInsertUpdate(DocumentEvent e)
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
fireRemoveUpdate(DocumentEvent e)
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
fireUndoableEditUpdate(UndoableEditEvent e)
Notifies all listeners that have registered interest for notification on this event type. |
int |
getAsynchronousLoadPriority()
Get the asynchronous loading priority. |
protected AbstractDocument.AttributeContext |
getAttributeContext()
Fetches the context for managing attributes. |
Element |
getBidiRootElement()
Returns the root element of the bidirectional structure for this document. |
protected AbstractDocument.Content |
getContent()
Gets the content for the document. |
protected Thread |
getCurrentWriter()
Fetches the current writing thread if there is one. |
abstract Element |
getDefaultRootElement()
Returns the root element that views should be based upon unless some other mechanism for assigning views to element structures is provided. |
Dictionary |
getDocumentProperties()
Support for managing a set of properties. |
Position |
getEndPosition()
Returns a position that represents the end of the document. |
int |
getLength()
Returns the length of the data. |
EventListener[] |
getListeners(Class listenerType)
Return an array of all the listeners of the given type that were added to this model. |
abstract Element |
getParagraphElement(int pos)
Get the paragraph element containing the given position. |
Object |
getProperty(Object key)
A convenience method for looking up a property value. |
Element[] |
getRootElements()
Gets all root elements defined. |
Position |
getStartPosition()
Returns a position that represents the start of the document. |
String |
getText(int offset,
int length)
Gets a sequence of text from the document. |
void |
getText(int offset,
int length,
Segment txt)
Gets some text from the document potentially without making a copy. |
void |
insertString(int offs,
String str,
AttributeSet a)
Inserts some content into the document. |
protected void |
insertUpdate(AbstractDocument.DefaultDocumentEvent chng,
AttributeSet attr)
Updates document structure as a result of text insertion. |
protected void |
postRemoveUpdate(AbstractDocument.DefaultDocumentEvent chng)
Updates any document structure as a result of text removal. |
void |
putProperty(Object key,
Object value)
A convenience method for storing up a property value. |
void |
readLock()
Acquires a lock to begin reading some state from the document. |
void |
readUnlock()
Does a read unlock. |
void |
remove(int offs,
int len)
Removes some content from the document. |
void |
removeDocumentListener(DocumentListener listener)
Removes a document listener. |
void |
removeUndoableEditListener(UndoableEditListener listener)
Removes an undo listener. |
protected void |
removeUpdate(AbstractDocument.DefaultDocumentEvent chng)
Updates any document structure as a result of text removal. |
void |
render(Runnable r)
This allows the model to be safely rendered in the presence of currency, if the model supports being updated asynchronously. |
void |
setAsynchronousLoadPriority(int p)
Set the asynchronous loading priority. |
void |
setDocumentProperties(Dictionary x)
Replace the document properties dictionary for this document. |
protected void |
writeLock()
Acquires a lock to begin mutating the document this lock protects. |
protected void |
writeUnlock()
Releases the write lock held because the write operation is finished. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
protected EventListenerList listenerList
protected static final String BAD_LOCATION
public static final String ParagraphElementName
public static final String ContentElementName
public static final String SectionElementName
public static final String BidiElementName
public static final String ElementNameAttribute
Constructor Detail |
protected AbstractDocument(AbstractDocument.Content data)
data
- the contentprotected AbstractDocument(AbstractDocument.Content data, AbstractDocument.AttributeContext context)
data
- the contentcontext
- the attribute contextMethod Detail |
public Dictionary getDocumentProperties()
setDocumentProperties(java.util.Dictionary)
public void setDocumentProperties(Dictionary x)
x
- the new dictionarygetDocumentProperties()
protected void fireInsertUpdate(DocumentEvent e)
e
- the eventEventListenerList
protected void fireChangedUpdate(DocumentEvent e)
e
- the eventEventListenerList
protected void fireRemoveUpdate(DocumentEvent e)
e
- the eventEventListenerList
protected void fireUndoableEditUpdate(UndoableEditEvent e)
e
- the eventEventListenerList
public EventListener[] getListeners(Class listenerType)
public int getAsynchronousLoadPriority()
public void setAsynchronousLoadPriority(int p)
public void render(Runnable r)
This is implemented to aquire a read lock for the duration of the runnables execution. There may be multiple runnables executing at the same time, and all writers will be blocked while there are active rendering runnables. If the runnable throws an exception, its lock will be safely released. There is no protection against a runnable that never exits, which will effectively leave the document locked for it's lifetime.
If the given runnable attempts to make any mutations in this implementation, a deadlock will occur. There is no tracking of individual rendering threads to enable detecting this situation, but a subclass could incur the overhead of tracking them and throwing an error.
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.
render
in interface Document
r
- the renderer to execute.public int getLength()
getLength
in interface Document
Document.getLength()
public void addDocumentListener(DocumentListener listener)
addDocumentListener
in interface Document
listener
- the listenerDocument.addDocumentListener(javax.swing.event.DocumentListener)
public void removeDocumentListener(DocumentListener listener)
removeDocumentListener
in interface Document
listener
- the listenerDocument.removeDocumentListener(javax.swing.event.DocumentListener)
public void addUndoableEditListener(UndoableEditListener listener)
addUndoableEditListener
in interface Document
listener
- the listenerDocument.addUndoableEditListener(javax.swing.event.UndoableEditListener)
public void removeUndoableEditListener(UndoableEditListener listener)
removeUndoableEditListener
in interface Document
listener
- the listenerDocument.removeDocumentListener(javax.swing.event.DocumentListener)
public final Object getProperty(Object key)
getDocumentProperties().get(key);
getProperty
in interface Document
key
- the non-null property keygetDocumentProperties()
public final void putProperty(Object key, Object value)
getDocumentProperties().put(key, value);If value is null this method will remove the property
putProperty
in interface Document
key
- the non-null keyvalue
- the valuegetDocumentProperties()
public void remove(int offs, int len) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.
remove
in interface Document
offs
- the starting offset >= 0len
- the number of characters to remove >= 0BadLocationException
- the given remove position is not a valid
position within the documentDocument.remove(int, int)
public void insertString(int offs, String str, AttributeSet a) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.
insertString
in interface Document
offs
- the starting offset >= 0str
- the string to insert; does nothing with null/empty stringsa
- the attributes for the inserted contentBadLocationException
- the given insert position is not a valid
position within the documentDocument.insertString(int, java.lang.String, javax.swing.text.AttributeSet)
public String getText(int offset, int length) throws BadLocationException
getText
in interface Document
offset
- the starting offset >= 0length
- the number of characters to retrieve >= 0BadLocationException
- the range given includes a position
that is not a valid position within the documentDocument.getText(int, int)
public void getText(int offset, int length, Segment txt) throws BadLocationException
Segment
should never be mutated.
This kind of access to the characters of the document
is provided to help make the rendering potentially more
efficient. The caller should make no assumptions about
the lifetime of the returned character array, which
should be copied if needed beyond the use for rendering.getText
in interface Document
offset
- the starting offset >= 0length
- the number of characters to retrieve >= 0txt
- the Segment object to retrieve the text intoBadLocationException
- the range given includes a position
that is not a valid position within the documentpublic Position createPosition(int offs) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.
createPosition
in interface Document
offs
- the position in the model >= 0BadLocationException
- if the given position does not
represent a valid location in the associated documentDocument.createPosition(int)
public final Position getStartPosition()
getStartPosition
in interface Document
public final Position getEndPosition()
getEndPosition
in interface Document
public Element[] getRootElements()
getRootElements
in interface Document
public abstract Element getDefaultRootElement()
getDefaultRootElement
in interface Document
Document.getDefaultRootElement()
public Element getBidiRootElement()
public abstract Element getParagraphElement(int pos)
pos
- the starting offset >= 0protected final AbstractDocument.AttributeContext getAttributeContext()
protected void insertUpdate(AbstractDocument.DefaultDocumentEvent chng, AttributeSet attr)
chng
- a description of the changeattr
- the attributes for the changeprotected void removeUpdate(AbstractDocument.DefaultDocumentEvent chng)
chng
- a description of the changeprotected void postRemoveUpdate(AbstractDocument.DefaultDocumentEvent chng)
chng
- a description of the changepublic void dump(PrintStream out)
out
- the output streamprotected final AbstractDocument.Content getContent()
protected Element createLeafElement(Element parent, AttributeSet a, int p0, int p1)
parent
- the parent elementa
- the attributes for the elementp0
- the beginning of the range >= 0p1
- the end of the range >= p0protected Element createBranchElement(Element parent, AttributeSet a)
parent
- the parent elementa
- the attributesprotected final Thread getCurrentWriter()
protected final void writeLock()
IllegalStateException
- thrown on illegal lock
attempt. If the document is implemented properly, this can
only happen if a document listener attempts to mutate the
document. This situation violates the bean event model
where order of delivery is not guaranteed and all listeners
should be notified before further mutations are allowed.protected final void writeUnlock()
public final void readLock()
readUnlock
.readUnlock()
public final void readUnlock()
readLock();
try {
// do something
} finally {
readUnlock();
}
readLock()
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JavaTM 2 Platform Std. Ed. v1.3 |
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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
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