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PlainDocument (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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JavaTM 2 Platform
Std. Ed. v1.4.1
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javax.swing.text
Class PlainDocument

java.lang.Object
  |
  +--javax.swing.text.AbstractDocument
        |
        +--javax.swing.text.PlainDocument
All Implemented Interfaces:
Document, Serializable
public class PlainDocument
extends AbstractDocument

A plain document that maintains no character attributes. The default element structure for this document is a map of the lines in the text. The Element returned by getDefaultRootElement is a map of the lines, and each child element represents a line. This model does not maintain any character level attributes, but each line can be tagged with an arbitrary set of attributes. Line to offset, and offset to line translations can be quickly performed using the default root element. The structure information of the DocumentEvent's fired by edits will indicate the line structure changes.

The default content storage management is performed by a gapped buffer implementation (GapContent). It supports editing reasonably large documents with good efficiency when the edits are contiguous or clustered, as is typical.

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 XMLEncoder.

See Also:
Document, AbstractDocument

Nested Class Summary
 
Nested classes inherited from class javax.swing.text.AbstractDocument
AbstractDocument.AbstractElement, AbstractDocument.AttributeContext, AbstractDocument.BranchElement, AbstractDocument.Content, AbstractDocument.DefaultDocumentEvent, AbstractDocument.ElementEdit, AbstractDocument.LeafElement
 
Field Summary
static String lineLimitAttribute
          Name of the attribute that specifies the maximum length of a line, if there is a maximum length.
static String tabSizeAttribute
          Name of the attribute that specifies the tab size for tabs contained in the content.
 
Fields inherited from class javax.swing.text.AbstractDocument
BAD_LOCATION, BidiElementName, ContentElementName, ElementNameAttribute, listenerList, ParagraphElementName, SectionElementName
 
Fields inherited from interface javax.swing.text.Document
StreamDescriptionProperty, TitleProperty
 
Constructor Summary
PlainDocument()
          Constructs a plain text document.
PlainDocument(AbstractDocument.Content c)
          Constructs a plain text document.
 
Method Summary
protected  AbstractDocument.AbstractElement createDefaultRoot()
          Creates the root element to be used to represent the default document structure.
 Element getDefaultRootElement()
          Gets the default root element for the document model.
 Element getParagraphElement(int pos)
          Get the paragraph element containing the given position.
 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 removeUpdate(AbstractDocument.DefaultDocumentEvent chng)
          Updates any document structure as a result of text removal.
 
Methods inherited from class javax.swing.text.AbstractDocument
addDocumentListener, addUndoableEditListener, createBranchElement, createLeafElement, createPosition, dump, fireChangedUpdate, fireInsertUpdate, fireRemoveUpdate, fireUndoableEditUpdate, getAsynchronousLoadPriority, getAttributeContext, getBidiRootElement, getContent, getCurrentWriter, getDocumentFilter, getDocumentListeners, getDocumentProperties, getEndPosition, getLength, getListeners, getProperty, getRootElements, getStartPosition, getText, getText, getUndoableEditListeners, postRemoveUpdate, putProperty, readLock, readUnlock, remove, removeDocumentListener, removeUndoableEditListener, render, replace, setAsynchronousLoadPriority, setDocumentFilter, setDocumentProperties, writeLock, writeUnlock
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

tabSizeAttribute

public static final String tabSizeAttribute
Name of the attribute that specifies the tab size for tabs contained in the content. The type for the value is Integer.

See Also:
Constant Field Values

lineLimitAttribute

public static final String lineLimitAttribute
Name of the attribute that specifies the maximum length of a line, if there is a maximum length. The type for the value is Integer.

See Also:
Constant Field Values
Constructor Detail

PlainDocument

public PlainDocument()
Constructs a plain text document. A default model using GapContent is constructed and set.

PlainDocument

public PlainDocument(AbstractDocument.Content c)
Constructs a plain text document. A default root element is created, and the tab size set to 8.

Parameters:
c - the container for the content
Method Detail

insertString

public void insertString(int offs,
                         String str,
                         AttributeSet a)
                  throws BadLocationException
Inserts some content into the document. Inserting content causes a write lock to be held while the actual changes are taking place, followed by notification to the observers on the thread that grabbed the write lock.

This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information.

Specified by:
insertString in interface Document
Overrides:
insertString in class AbstractDocument
Parameters:
offs - the starting offset >= 0
str - the string to insert; does nothing with null/empty strings
a - the attributes for the inserted content
Throws:
BadLocationException - the given insert position is not a valid position within the document
See Also:
Document.insertString(int, java.lang.String, javax.swing.text.AttributeSet)

getDefaultRootElement

public Element getDefaultRootElement()
Gets the default root element for the document model.

Specified by:
getDefaultRootElement in interface Document
Specified by:
getDefaultRootElement in class AbstractDocument
Returns:
the root
See Also:
Document.getDefaultRootElement()

createDefaultRoot

protected AbstractDocument.AbstractElement createDefaultRoot()
Creates the root element to be used to represent the default document structure.

Returns:
the element base

getParagraphElement

public Element getParagraphElement(int pos)
Get the paragraph element containing the given position. Since this document only models lines, it returns the line instead.

Specified by:
getParagraphElement in class AbstractDocument
Parameters:
pos - the starting offset >= 0
Returns:
the element

insertUpdate

protected void insertUpdate(AbstractDocument.DefaultDocumentEvent chng,
                            AttributeSet attr)
Updates document structure as a result of text insertion. This will happen within a write lock. Since this document simply maps out lines, we refresh the line map.

Overrides:
insertUpdate in class AbstractDocument
Parameters:
chng - the change event describing the dit
attr - the set of attributes for the inserted text

removeUpdate

protected void removeUpdate(AbstractDocument.DefaultDocumentEvent chng)
Updates any document structure as a result of text removal. This will happen within a write lock. Since the structure represents a line map, this just checks to see if the removal spans lines. If it does, the two lines outside of the removal area are joined together.

Overrides:
removeUpdate in class AbstractDocument
Parameters:
chng - the change event describing the edit
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JavaTM 2 Platform
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.