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public abstract class AbstractDocument extends Object implements Document, Serializable
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 acquired 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
independent 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. As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans
package.
Please see {@link java.beans.XMLEncoder}.
Nested Class Summary | |
---|---|
abstract class |
Implements the abstract part of an element. |
static interface |
An interface that can be used to allow MutableAttributeSet implementations to use pluggable attribute compression techniques. |
class |
Implements a composite element that contains other elements. |
static interface |
Interface to describe a sequence of character content that can be edited. |
class |
Stores document changes as the document is being modified. |
static class |
An implementation of ElementChange that can be added to the document event. |
class |
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). |
Constructor Summary | |
---|---|
protected |
Constructs a new AbstractDocument , wrapped around some
specified content storage mechanism.
|
protected |
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 |
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
Notifies all listeners that have registered interest for notification on this event type. |
protected void |
Notifies all listeners that have registered interest for notification on this event type. |
int |
Gets the asynchronous loading priority. |
protected AbstractDocument.AttributeContext |
Fetches the context for managing attributes. |
Element |
Returns the root element of the bidirectional structure for this document. |
protected AbstractDocument.Content |
Gets the content for the document. |
protected Thread |
Fetches the current writing thread if there is one. |
abstract Element |
Returns the root element that views should be based upon unless some other mechanism for assigning views to element structures is provided. |
DocumentFilter |
Returns the DocumentFilter that is responsible for
filtering of insertion/removal.
|
DocumentListener[] |
Returns an array of all the document listeners registered on this document. |
Dictionary |
Supports managing a set of properties. |
Position |
Returns a position that represents the end of the document. |
int |
Returns the length of the data. |
EventListener[] |
getListeners(Class listenerType) Returns an array of all the objects currently registered as FooListener s
upon this document.
|
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[] |
Gets all root elements defined. |
Position |
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 |
Fetches the text contained within the given portion of the document. |
UndoableEditListener[] |
Returns an array of all the undoable edit listeners registered on this document. |
void |
insertString(int offs, String str, AttributeSet a) Inserts some content into the document. |
protected void |
Updates document structure as a result of text insertion. |
protected void |
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 |
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 |
Removes an undo listener. |
protected void |
Updates any document structure as a result of text removal. |
void |
This allows the model to be safely rendered in the presence of currency, if the model supports being updated asynchronously. |
void |
replace(int offset, int length, String text, AttributeSet attrs) Deletes the region of text from offset to
offset + length , and replaces it with text .
|
void |
setAsynchronousLoadPriority(int p) Sets the asynchronous loading priority. |
void |
setDocumentFilter(DocumentFilter filter) Sets the DocumentFilter .
|
void |
Replaces the document properties dictionary for this document. |
protected void |
Acquires a lock to begin mutating the document this lock protects. |
protected void |
Releases a write lock previously obtained via writeLock .
|
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
protected static final String BAD_LOCATION
public static final String BidiElementName
public static final String ContentElementName
public static final String ElementNameAttribute
protected EventListenerList listenerList
public static final String ParagraphElementName
public static final String SectionElementName
Constructor Detail |
---|
protected AbstractDocument(AbstractDocument.Content data)
AbstractDocument
, wrapped around some
specified content storage mechanism.
data
- the contentprotected AbstractDocument(AbstractDocument.Content data, AbstractDocument.AttributeContext context)
AbstractDocument
, wrapped around some
specified content storage mechanism.
data
- the contentcontext
- the attribute contextMethod Detail |
---|
public void addDocumentListener(DocumentListener listener)
listener
- the DocumentListener
to addpublic void addUndoableEditListener(UndoableEditListener listener)
UndoableEdit
will cause the appropriate DocumentEvent to be fired to keep
the view(s) in sync with the model.
listener
- the UndoableEditListener
to addprotected Element createBranchElement(Element parent, AttributeSet a)
parent
- the parent elementa
- the attributesprotected 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 >= p0public synchronized Position createPosition(int offs) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
offs
- the position in the model >= 0BadLocationException
- if the given position does not
represent a valid location in the associated documentpublic void dump(PrintStream out)
out
- the output streamprotected void fireChangedUpdate(DocumentEvent e)
e
- the eventprotected void fireInsertUpdate(DocumentEvent e)
e
- the eventprotected void fireRemoveUpdate(DocumentEvent e)
e
- the eventprotected void fireUndoableEditUpdate(UndoableEditEvent e)
e
- the eventpublic int getAsynchronousLoadPriority()
-1
if the document should not be loaded asynchronouslyprotected final AbstractDocument.AttributeContext getAttributeContext()
public Element getBidiRootElement()
protected final AbstractDocument.Content getContent()
protected final synchronized Thread getCurrentWriter()
null
if there are no modifications in progresspublic abstract Element getDefaultRootElement()
public DocumentFilter getDocumentFilter()
DocumentFilter
that is responsible for
filtering of insertion/removal. A null
return value
implies no filtering is to occur.
public DocumentListener[] getDocumentListeners()
DocumentListener
s
or an empty array if no document listeners are
currently registeredpublic Dictionary getDocumentProperties()
documentProperties
dictionary
to annotate the document with document-wide properties.
null
Dictionary
public final Position getEndPosition()
public int getLength()
public EventListener[] getListeners(Class listenerType)
FooListener
s
upon this document.
FooListener
s are registered using the
addFooListener
method.
You can specify the listenerType
argument
with a class literal, such as
FooListener.class
.
For example, you can query a
document d
for its document listeners with the following code:
DocumentListener[] mls = (DocumentListener[])(d.getListeners(DocumentListener.class));If no such listeners exist, this method returns an empty array.
listenerType
- the type of listeners requested; this parameter
should specify an interface that descends from
java.util.EventListener
FooListener
s on this component,
or an empty array if no such
listeners have been addedpublic abstract Element getParagraphElement(int pos)
pos
- the starting offset >= 0public final Object getProperty(Object key)
getDocumentProperties().get(key);
key
- the non-null
property keynull
public Element[] getRootElements()
public final Position getStartPosition()
public String getText(int offset, int length) throws BadLocationException
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 documentpublic void getText(int offset, int length, Segment txt) throws BadLocationException
If the partialReturn property on the txt parameter is false, the data returned in the Segment will be the entire length requested and may or may not be a copy depending upon how the data was stored. If the partialReturn property is true, only the amount of text that can be returned without creating a copy is returned. Using partial returns will give better performance for situations where large parts of the document are being scanned. The following is an example of using the partial return to access the entire document:
int nleft = doc.getDocumentLength(); Segment text = new Segment(); int offs = 0; text.setPartialReturn(true); while (nleft > 0) { doc.getText(offs, nleft, text); // do something with text nleft -= text.count; offs += text.count; }
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 UndoableEditListener[] getUndoableEditListeners()
UndoableEditListener
s
or an empty array if no undoable edit listeners are
currently registeredpublic void insertString(int offs, String str, AttributeSet a) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
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 documentprotected void insertUpdate(AbstractDocument.DefaultDocumentEvent chng, AttributeSet attr)
chng
- a description of the changeattr
- the attributes for the changeprotected void postRemoveUpdate(AbstractDocument.DefaultDocumentEvent chng)
chng
- a description of the changepublic final void putProperty(Object key, Object value)
getDocumentProperties().put(key, value);If
value
is null
this method will
remove the property.
key
- the non-null
keyvalue
- the property valuepublic final synchronized void readLock()
readUnlock
.
public final synchronized void readUnlock()
readLock();
try {
// do something
} finally {
readUnlock();
}
public void remove(int offs, int len) throws BadLocationException
This method is thread safe, although most Swing methods are not. Please see How to Use Threads for more information.
offs
- the starting offset >= 0len
- the number of characters to remove >= 0BadLocationException
- the given remove position is not a valid
position within the documentpublic void removeDocumentListener(DocumentListener listener)
listener
- the DocumentListener
to removepublic void removeUndoableEditListener(UndoableEditListener listener)
listener
- the UndoableEditListener
to removeprotected void removeUpdate(AbstractDocument.DefaultDocumentEvent chng)
chng
- a description of the changepublic 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 How to Use Threads for more information.
r
- the renderer to executepublic void replace(int offset, int length, String text, AttributeSet attrs) throws BadLocationException
offset
to
offset + length
, and replaces it with text
.
It is up to the implementation as to how this is implemented, some
implementations may treat this as two distinct operations: a remove
followed by an insert, others may treat the replace as one atomic
operation.
offset
- index of child elementlength
- length of text to delete, may be 0 indicating don't
delete anythingtext
- text to insert, null
indicates no text to insertattrs
- AttributeSet indicating attributes of inserted text,
null
is legal, and typically treated as an empty attributeset,
but exact interpretation is left to the subclassBadLocationException
- the given position is not a valid
position within the documentpublic void setAsynchronousLoadPriority(int p)
p
- the new asynchronous loading priority; a value
less than zero indicates that the document should not be
loaded asynchronouslypublic void setDocumentFilter(DocumentFilter filter)
DocumentFilter
. The DocumentFilter
is passed insert
and remove
to conditionally
allow inserting/deleting of the text. A null
value
indicates that no filtering will occur.
filter
- the DocumentFilter
used to constrain textpublic void setDocumentProperties(Dictionary x)
x
- the new dictionaryprotected final synchronized void writeLock()
writeLock
,
as long as it doesn't attempt to gain additional writeLock
s
from within document notification. Attempting to gain a
writeLock
from within a DocumentListener notification will
result in an IllegalStateException
. The ability
to obtain more than one writeLock
per thread allows
subclasses to gain a writeLock, perform a number of operations, then
release the lock.
Calls to writeLock
must be balanced with calls to writeUnlock
, else the
Document
will be left in a locked state so that no
reading or writing can be done.
protected final synchronized void writeUnlock()
writeLock
.
After decrementing the lock count if there are no oustanding locks
this will allow a new writer, or readers.
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