Java™ Platform
Standard Ed. 6

javax.swing.text.html
Class HTMLEditorKit

java.lang.Object
  extended by javax.swing.text.EditorKit
      extended by javax.swing.text.DefaultEditorKit
          extended by javax.swing.text.StyledEditorKit
              extended by javax.swing.text.html.HTMLEditorKit
All Implemented Interfaces:
Serializable, Cloneable, Accessible

public class HTMLEditorKit
extends StyledEditorKit
implements Accessible

The Swing JEditorPane text component supports different kinds of content via a plug-in mechanism called an EditorKit. Because HTML is a very popular format of content, some support is provided by default. The default support is provided by this class, which supports HTML version 3.2 (with some extensions), and is migrating toward version 4.0. The <applet> tag is not supported, but some support is provided for the <object> tag.

There are several goals of the HTML EditorKit provided, that have an effect upon the way that HTML is modeled. These have influenced its design in a substantial way.

Support editing
It might seem fairly obvious that a plug-in for JEditorPane should provide editing support, but that fact has several design considerations. There are a substantial number of HTML documents that don't properly conform to an HTML specification. These must be normalized somewhat into a correct form if one is to edit them. Additionally, users don't like to be presented with an excessive amount of structure editing, so using traditional text editing gestures is preferred over using the HTML structure exactly as defined in the HTML document.

The modeling of HTML is provided by the class HTMLDocument. Its documention describes the details of how the HTML is modeled. The editing support leverages heavily off of the text package.

Extendable/Scalable
To maximize the usefulness of this kit, a great deal of effort has gone into making it extendable. These are some of the features.
  1. The parser is replacable. The default parser is the Hot Java parser which is DTD based. A different DTD can be used, or an entirely different parser can be used. To change the parser, reimplement the getParser method. The default parser is dynamically loaded when first asked for, so the class files will never be loaded if an alternative parser is used. The default parser is in a separate package called parser below this package.
  2. The parser drives the ParserCallback, which is provided by HTMLDocument. To change the callback, subclass HTMLDocument and reimplement the createDefaultDocument method to return document that produces a different reader. The reader controls how the document is structured. Although the Document provides HTML support by default, there is nothing preventing support of non-HTML tags that result in alternative element structures.
  3. The default view of the models are provided as a hierarchy of View implementations, so one can easily customize how a particular element is displayed or add capabilities for new kinds of elements by providing new View implementations. The default set of views are provided by the HTMLFactory class. This can be easily changed by subclassing or replacing the HTMLFactory and reimplementing the getViewFactory method to return the alternative factory.
  4. The View implementations work primarily off of CSS attributes, which are kept in the views. This makes it possible to have multiple views mapped over the same model that appear substantially different. This can be especially useful for printing. For most HTML attributes, the HTML attributes are converted to CSS attributes for display. This helps make the View implementations more general purpose

Asynchronous Loading
Larger documents involve a lot of parsing and take some time to load. By default, this kit produces documents that will be loaded asynchronously if loaded using JEditorPane.setPage. This is controlled by a property on the document. The method createDefaultDocument can be overriden to change this. The batching of work is done by the HTMLDocument.HTMLReader class. The actual work is done by the DefaultStyledDocument and AbstractDocument classes in the text package.

Customization from current LAF
HTML provides a well known set of features without exactly specifying the display characteristics. Swing has a theme mechanism for its look-and-feel implementations. It is desirable for the look-and-feel to feed display characteristics into the HTML views. An user with poor vision for example would want high contrast and larger than typical fonts.

The support for this is provided by the StyleSheet class. The presentation of the HTML can be heavily influenced by the setting of the StyleSheet property on the EditorKit.

Not lossy
An EditorKit has the ability to be read and save documents. It is generally the most pleasing to users if there is no loss of data between the two operation. The policy of the HTMLEditorKit will be to store things not recognized or not necessarily visible so they can be subsequently written out. The model of the HTML document should therefore contain all information discovered while reading the document. This is constrained in some ways by the need to support editing (i.e. incorrect documents sometimes must be normalized). The guiding principle is that information shouldn't be lost, but some might be synthesized to produce a more correct model or it might be rearranged.


Nested Class Summary
static class HTMLEditorKit.HTMLFactory
          A factory to build views for HTML.
static class HTMLEditorKit.HTMLTextAction
          An abstract Action providing some convenience methods that may be useful in inserting HTML into an existing document.
static class HTMLEditorKit.InsertHTMLTextAction
          InsertHTMLTextAction can be used to insert an arbitrary string of HTML into an existing HTML document.
static class HTMLEditorKit.LinkController
          Class to watch the associated component and fire hyperlink events on it when appropriate.
static class HTMLEditorKit.Parser
          Interface to be supported by the parser.
static class HTMLEditorKit.ParserCallback
          The result of parsing drives these callback methods.
 
Nested classes/interfaces inherited from class javax.swing.text.StyledEditorKit
StyledEditorKit.AlignmentAction, StyledEditorKit.BoldAction, StyledEditorKit.FontFamilyAction, StyledEditorKit.FontSizeAction, StyledEditorKit.ForegroundAction, StyledEditorKit.ItalicAction, StyledEditorKit.StyledTextAction, StyledEditorKit.UnderlineAction
 
Nested classes/interfaces inherited from class javax.swing.text.DefaultEditorKit
DefaultEditorKit.BeepAction, DefaultEditorKit.CopyAction, DefaultEditorKit.CutAction, DefaultEditorKit.DefaultKeyTypedAction, DefaultEditorKit.InsertBreakAction, DefaultEditorKit.InsertContentAction, DefaultEditorKit.InsertTabAction, DefaultEditorKit.PasteAction
 
Field Summary
static String BOLD_ACTION
          The bold action identifier
static String COLOR_ACTION
          The Color choice action identifier The color is passed as an argument
static String DEFAULT_CSS
          Default Cascading Style Sheet file that sets up the tag views.
static String FONT_CHANGE_BIGGER
          The font size increase to next value action identifier
static String FONT_CHANGE_SMALLER
          The font size decrease to next value action identifier
static String IMG_ALIGN_BOTTOM
          Align images at the bottom.
static String IMG_ALIGN_MIDDLE
          Align images in the middle.
static String IMG_ALIGN_TOP
          Align images at the top.
static String IMG_BORDER
          Align images at the border.
static String ITALIC_ACTION
          The italic action identifier
static String LOGICAL_STYLE_ACTION
          The logical style choice action identifier The logical style is passed in as an argument
static String PARA_INDENT_LEFT
          The paragraph left indent action identifier
static String PARA_INDENT_RIGHT
          The paragraph right indent action identifier
 
Fields inherited from class javax.swing.text.DefaultEditorKit
backwardAction, beepAction, beginAction, beginLineAction, beginParagraphAction, beginWordAction, copyAction, cutAction, defaultKeyTypedAction, deleteNextCharAction, deleteNextWordAction, deletePrevCharAction, deletePrevWordAction, downAction, endAction, endLineAction, EndOfLineStringProperty, endParagraphAction, endWordAction, forwardAction, insertBreakAction, insertContentAction, insertTabAction, nextWordAction, pageDownAction, pageUpAction, pasteAction, previousWordAction, readOnlyAction, selectAllAction, selectionBackwardAction, selectionBeginAction, selectionBeginLineAction, selectionBeginParagraphAction, selectionBeginWordAction, selectionDownAction, selectionEndAction, selectionEndLineAction, selectionEndParagraphAction, selectionEndWordAction, selectionForwardAction, selectionNextWordAction, selectionPreviousWordAction, selectionUpAction, selectLineAction, selectParagraphAction, selectWordAction, upAction, writableAction
 
Constructor Summary
HTMLEditorKit()
          Constructs an HTMLEditorKit, creates a StyleContext, and loads the style sheet.
 
Method Summary
 Object clone()
          Creates a copy of the editor kit.
 Document createDefaultDocument()
          Create an uninitialized text storage model that is appropriate for this type of editor.
protected  void createInputAttributes(Element element, MutableAttributeSet set)
          Copies the key/values in elements AttributeSet into set.
 void deinstall(JEditorPane c)
          Called when the kit is being removed from the JEditorPane.
 AccessibleContext getAccessibleContext()
          returns the AccessibleContext associated with this editor kit
 Action[] getActions()
          Fetches the command list for the editor.
 String getContentType()
          Get the MIME type of the data that this kit represents support for.
 Cursor getDefaultCursor()
          Returns the default cursor.
 MutableAttributeSet getInputAttributes()
          Gets the input attributes used for the styled editing actions.
 Cursor getLinkCursor()
          Returns the cursor to use over hyper links.
protected  HTMLEditorKit.Parser getParser()
          Fetch the parser to use for reading HTML streams.
 StyleSheet getStyleSheet()
          Get the set of styles currently being used to render the HTML elements.
 ViewFactory getViewFactory()
          Fetch a factory that is suitable for producing views of any models that are produced by this kit.
 void insertHTML(HTMLDocument doc, int offset, String html, int popDepth, int pushDepth, HTML.Tag insertTag)
          Inserts HTML into an existing document.
 void install(JEditorPane c)
          Called when the kit is being installed into the a JEditorPane.
 boolean isAutoFormSubmission()
          Indicates whether an html form submission is processed automatically or only FormSubmitEvent is fired.
 void read(Reader in, Document doc, int pos)
          Inserts content from the given stream.
 void setAutoFormSubmission(boolean isAuto)
          Specifies if an html form submission is processed automatically or only FormSubmitEvent is fired.
 void setDefaultCursor(Cursor cursor)
          Sets the default cursor.
 void setLinkCursor(Cursor cursor)
          Sets the cursor to use over links.
 void setStyleSheet(StyleSheet s)
          Set the set of styles to be used to render the various HTML elements.
 void write(Writer out, Document doc, int pos, int len)
          Write content from a document to the given stream in a format appropriate for this kind of content handler.
 
Methods inherited from class javax.swing.text.StyledEditorKit
getCharacterAttributeRun
 
Methods inherited from class javax.swing.text.DefaultEditorKit
createCaret, read, write
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

DEFAULT_CSS

public static final String DEFAULT_CSS
Default Cascading Style Sheet file that sets up the tag views.

See Also:
Constant Field Values

BOLD_ACTION

public static final String BOLD_ACTION
The bold action identifier

See Also:
Constant Field Values

ITALIC_ACTION

public static final String ITALIC_ACTION
The italic action identifier

See Also:
Constant Field Values

PARA_INDENT_LEFT

public static final String PARA_INDENT_LEFT
The paragraph left indent action identifier

See Also:
Constant Field Values

PARA_INDENT_RIGHT

public static final String PARA_INDENT_RIGHT
The paragraph right indent action identifier

See Also:
Constant Field Values

FONT_CHANGE_BIGGER

public static final String FONT_CHANGE_BIGGER
The font size increase to next value action identifier

See Also:
Constant Field Values

FONT_CHANGE_SMALLER

public static final String FONT_CHANGE_SMALLER
The font size decrease to next value action identifier

See Also:
Constant Field Values

COLOR_ACTION

public static final String COLOR_ACTION
The Color choice action identifier The color is passed as an argument

See Also:
Constant Field Values

LOGICAL_STYLE_ACTION

public static final String LOGICAL_STYLE_ACTION
The logical style choice action identifier The logical style is passed in as an argument

See Also:
Constant Field Values

IMG_ALIGN_TOP

public static final String IMG_ALIGN_TOP
Align images at the top.

See Also:
Constant Field Values

IMG_ALIGN_MIDDLE

public static final String IMG_ALIGN_MIDDLE
Align images in the middle.

See Also:
Constant Field Values

IMG_ALIGN_BOTTOM

public static final String IMG_ALIGN_BOTTOM
Align images at the bottom.

See Also:
Constant Field Values

IMG_BORDER

public static final String IMG_BORDER
Align images at the border.

See Also:
Constant Field Values
Constructor Detail

HTMLEditorKit

public HTMLEditorKit()
Constructs an HTMLEditorKit, creates a StyleContext, and loads the style sheet.

Method Detail

getContentType

public String getContentType()
Get the MIME type of the data that this kit represents support for. This kit supports the type text/html.

Overrides:
getContentType in class DefaultEditorKit
Returns:
the type

getViewFactory

public ViewFactory getViewFactory()
Fetch a factory that is suitable for producing views of any models that are produced by this kit.

Overrides:
getViewFactory in class StyledEditorKit
Returns:
the factory

createDefaultDocument

public Document createDefaultDocument()
Create an uninitialized text storage model that is appropriate for this type of editor.

Overrides:
createDefaultDocument in class StyledEditorKit
Returns:
the model

read

public void read(Reader in,
                 Document doc,
                 int pos)
          throws IOException,
                 BadLocationException
Inserts content from the given stream. If doc is an instance of HTMLDocument, this will read HTML 3.2 text. Inserting HTML into a non-empty document must be inside the body Element, if you do not insert into the body an exception will be thrown. When inserting into a non-empty document all tags outside of the body (head, title) will be dropped.

Overrides:
read in class DefaultEditorKit
Parameters:
in - the stream to read from
doc - the destination for the insertion
pos - the location in the document to place the content
Throws:
IOException - on any I/O error
BadLocationException - if pos represents an invalid location within the document
RuntimeException - (will eventually be a BadLocationException) if pos is invalid

insertHTML

public void insertHTML(HTMLDocument doc,
                       int offset,
                       String html,
                       int popDepth,
                       int pushDepth,
                       HTML.Tag insertTag)
                throws BadLocationException,
                       IOException
Inserts HTML into an existing document.

Parameters:
doc - the document to insert into
offset - the offset to insert HTML at
popDepth - the number of ElementSpec.EndTagTypes to generate before inserting
pushDepth - the number of ElementSpec.StartTagTypes with a direction of ElementSpec.JoinNextDirection that should be generated before inserting, but after the end tags have been generated
insertTag - the first tag to start inserting into document
Throws:
RuntimeException - (will eventually be a BadLocationException) if pos is invalid
BadLocationException
IOException

write

public void write(Writer out,
                  Document doc,
                  int pos,
                  int len)
           throws IOException,
                  BadLocationException
Write content from a document to the given stream in a format appropriate for this kind of content handler.

Overrides:
write in class DefaultEditorKit
Parameters:
out - the stream to write to
doc - the source for the write
pos - the location in the document to fetch the content
len - the amount to write out
Throws:
IOException - on any I/O error
BadLocationException - if pos represents an invalid location within the document

install

public void install(JEditorPane c)
Called when the kit is being installed into the a JEditorPane.

Overrides:
install in class StyledEditorKit
Parameters:
c - the JEditorPane

deinstall

public void deinstall(JEditorPane c)
Called when the kit is being removed from the JEditorPane. This is used to unregister any listeners that were attached.

Overrides:
deinstall in class StyledEditorKit
Parameters:
c - the JEditorPane

setStyleSheet

public void setStyleSheet(StyleSheet s)
Set the set of styles to be used to render the various HTML elements. These styles are specified in terms of CSS specifications. Each document produced by the kit will have a copy of the sheet which it can add the document specific styles to. By default, the StyleSheet specified is shared by all HTMLEditorKit instances. This should be reimplemented to provide a finer granularity if desired.


getStyleSheet

public StyleSheet getStyleSheet()
Get the set of styles currently being used to render the HTML elements. By default the resource specified by DEFAULT_CSS gets loaded, and is shared by all HTMLEditorKit instances.


getActions

public Action[] getActions()
Fetches the command list for the editor. This is the list of commands supported by the superclass augmented by the collection of commands defined locally for style operations.

Overrides:
getActions in class StyledEditorKit
Returns:
the command list

createInputAttributes

protected void createInputAttributes(Element element,
                                     MutableAttributeSet set)
Copies the key/values in elements AttributeSet into set. This does not copy component, icon, or element names attributes. Subclasses may wish to refine what is and what isn't copied here. But be sure to first remove all the attributes that are in set.

This is called anytime the caret moves over a different location.

Overrides:
createInputAttributes in class StyledEditorKit

getInputAttributes

public MutableAttributeSet getInputAttributes()
Gets the input attributes used for the styled editing actions.

Overrides:
getInputAttributes in class StyledEditorKit
Returns:
the attribute set

setDefaultCursor

public void setDefaultCursor(Cursor cursor)
Sets the default cursor.

Since:
1.3

getDefaultCursor

public Cursor getDefaultCursor()
Returns the default cursor.

Since:
1.3

setLinkCursor

public void setLinkCursor(Cursor cursor)
Sets the cursor to use over links.

Since:
1.3

getLinkCursor

public Cursor getLinkCursor()
Returns the cursor to use over hyper links.

Since:
1.3

isAutoFormSubmission

public boolean isAutoFormSubmission()
Indicates whether an html form submission is processed automatically or only FormSubmitEvent is fired.

Returns:
true if html form submission is processed automatically, false otherwise.
Since:
1.5
See Also:
setAutoFormSubmission(boolean)

setAutoFormSubmission

public void setAutoFormSubmission(boolean isAuto)
Specifies if an html form submission is processed automatically or only FormSubmitEvent is fired. By default it is set to true.

Since:
1.5
See Also:
isAutoFormSubmission, FormSubmitEvent

clone

public Object clone()
Creates a copy of the editor kit.

Overrides:
clone in class StyledEditorKit
Returns:
the copy
See Also:
Cloneable

getParser

protected HTMLEditorKit.Parser getParser()
Fetch the parser to use for reading HTML streams. This can be reimplemented to provide a different parser. The default implementation is loaded dynamically to avoid the overhead of loading the default parser if it's not used. The default parser is the HotJava parser using an HTML 3.2 DTD.


getAccessibleContext

public AccessibleContext getAccessibleContext()
returns the AccessibleContext associated with this editor kit

Specified by:
getAccessibleContext in interface Accessible
Returns:
the AccessibleContext associated with this editor kit
Since:
1.4

Java™ Platform
Standard Ed. 6

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