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public class: HTMLEditorKit [javadoc | source]

All Implemented Interfaces:
    Accessible, Cloneable, Serializable

Direct Known Subclasses:
    MyHTMLEditorKit, BasicEditorKit

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.

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:
public static class  HTMLEditorKit.LinkController  Class to watch the associated component and fire hyperlink events on it when appropriate. 
abstract public static class  HTMLEditorKit.Parser  Interface to be supported by the parser. This enables providing a different parser while reusing some of the implementation provided by this editor kit. 
public static class  HTMLEditorKit.ParserCallback  The result of parsing drives these callback methods. The open and close actions should be balanced. The flush method will be the last method called, to give the receiver a chance to flush any pending data into the document.

Refer to DocumentParser, the default parser used, for further information on the contents of the AttributeSets, the positions, and other info. 

public static class  HTMLEditorKit.HTMLFactory  A factory to build views for HTML. The following table describes what this factory will build by default.
TagView created
abstract public static class  HTMLEditorKit.HTMLTextAction  An abstract Action providing some convenience methods that may be useful in inserting HTML into an existing document.

NOTE: None of the convenience methods obtain a lock on the document. If you have another thread modifying the text these methods may have inconsistent behavior, or return the wrong thing. 

public static class  HTMLEditorKit.InsertHTMLTextAction  InsertHTMLTextAction can be used to insert an arbitrary string of HTML into an existing HTML document. At least two HTML.Tags need to be supplied. The first Tag, parentTag, identifies the parent in the document to add the elements to. The second tag, addTag, identifies the first tag that should be added to the document as seen in the HTML string. One important thing to remember, is that the parser is going to generate all the appropriate tags, even if they aren't in the HTML string passed in.

For example, lets say you wanted to create an action to insert a table into the body. The parentTag would be HTML.Tag.BODY, addTag would be HTML.Tag.TABLE, and the string could be something like <table><tr><td></td></tr></table>.

There is also an option to supply an alternate parentTag and addTag. These will be checked for if there is no parentTag at offset. 

static class  HTMLEditorKit.InsertHRAction  InsertHRAction is special, at actionPerformed time it will determine the parent HTML.Tag based on the paragraph element at the selection start. 
static class  HTMLEditorKit.NavigateLinkAction   
static class  HTMLEditorKit.ActivateLinkAction   
static class  HTMLEditorKit.BeginAction   
Field Summary
public static final  String DEFAULT_CSS    Default Cascading Style Sheet file that sets up the tag views. 
 MutableAttributeSet input     
public static final  String BOLD_ACTION    The bold action identifier 
public static final  String ITALIC_ACTION    The italic action identifier 
public static final  String PARA_INDENT_LEFT    The paragraph left indent action identifier 
public static final  String PARA_INDENT_RIGHT    The paragraph right indent action identifier 
public static final  String FONT_CHANGE_BIGGER    The font size increase to next value action identifier 
public static final  String FONT_CHANGE_SMALLER    The font size decrease to next value action identifier 
public static final  String COLOR_ACTION    The Color choice action identifier The color is passed as an argument 
public static final  String LOGICAL_STYLE_ACTION    The logical style choice action identifier The logical style is passed in as an argument 
public static final  String IMG_ALIGN_TOP    Align images at the top. 
public static final  String IMG_ALIGN_MIDDLE    Align images in the middle. 
public static final  String IMG_ALIGN_BOTTOM    Align images at the bottom. 
public static final  String IMG_BORDER    Align images at the border. 
Fields inherited from javax.swing.text.StyledEditorKit:
currentRun,  currentParagraph,  inputAttributes
Fields inherited from javax.swing.text.DefaultEditorKit:
EndOfLineStringProperty,  insertContentAction,  insertBreakAction,  insertTabAction,  deletePrevCharAction,  deleteNextCharAction,  deleteNextWordAction,  deletePrevWordAction,  readOnlyAction,  writableAction,  cutAction,  copyAction,  pasteAction,  beepAction,  pageUpAction,  pageDownAction,  selectionPageUpAction,  selectionPageDownAction,  selectionPageLeftAction,  selectionPageRightAction,  forwardAction,  backwardAction,  selectionForwardAction,  selectionBackwardAction,  upAction,  downAction,  selectionUpAction,  selectionDownAction,  beginWordAction,  endWordAction,  selectionBeginWordAction,  selectionEndWordAction,  previousWordAction,  nextWordAction,  selectionPreviousWordAction,  selectionNextWordAction,  beginLineAction,  endLineAction,  selectionBeginLineAction,  selectionEndLineAction,  beginParagraphAction,  endParagraphAction,  selectionBeginParagraphAction,  selectionEndParagraphAction,  beginAction,  endAction,  selectionBeginAction,  selectionEndAction,  selectWordAction,  selectLineAction,  selectParagraphAction,  selectAllAction,  unselectAction,  toggleComponentOrientationAction,  defaultKeyTypedAction
 public HTMLEditorKit() 
Method from javax.swing.text.html.HTMLEditorKit Summary:
clone,   createDefaultDocument,   createInputAttributes,   deinstall,   getAccessibleContext,   getActions,   getContentType,   getDefaultCursor,   getInputAttributes,   getLinkCursor,   getParser,   getResourceAsStream,   getStyleSheet,   getViewFactory,   insertHTML,   install,   isAutoFormSubmission,   read,   setAutoFormSubmission,   setDefaultCursor,   setLinkCursor,   setStyleSheet,   write
Methods from javax.swing.text.StyledEditorKit:
clone,   createDefaultDocument,   createInputAttributes,   deinstall,   getActions,   getCharacterAttributeRun,   getInputAttributes,   getViewFactory,   install
Methods from javax.swing.text.DefaultEditorKit:
createCaret,   createDefaultDocument,   getActions,   getContentType,   getInputAttributes,   getViewFactory,   read,   read,   write,   write
Methods from javax.swing.text.EditorKit:
clone,   createCaret,   createDefaultDocument,   deinstall,   getActions,   getContentType,   getViewFactory,   install,   read,   read,   write,   write
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from javax.swing.text.html.HTMLEditorKit Detail:
 public Object clone() 
    Creates a copy of the editor kit.
 public 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. 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.

 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.
 public AccessibleContext getAccessibleContext() 
    returns the AccessibleContext associated with this editor kit
 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.
 public String getContentType() 
    Get the MIME type of the data that this kit represents support for. This kit supports the type text/html.
 public Cursor getDefaultCursor() 
    Returns the default cursor.
 public MutableAttributeSet getInputAttributes() 
    Gets the input attributes used for the styled editing actions.
 public Cursor getLinkCursor() 
    Returns the cursor to use over hyper links.
 protected 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.
 static InputStream getResourceAsStream(String name) 
    Fetch a resource relative to the HTMLEditorKit classfile. If this is called on 1.2 the loading will occur under the protection of a doPrivileged call to allow the HTMLEditorKit to function when used in an applet.
 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.
 public ViewFactory getViewFactory() 
    Fetch a factory that is suitable for producing views of any models that are produced by this kit.
 public  void insertHTML(HTMLDocument doc,
    int offset,
    String html,
    int popDepth,
    int pushDepth,
    Tag insertTag) throws BadLocationException, IOException 
    Inserts HTML into an existing document.
 public  void install(JEditorPane c) 
    Called when the kit is being installed into the a JEditorPane.
 public boolean isAutoFormSubmission() 
    Indicates whether an html form submission is processed automatically or only FormSubmitEvent is fired.
 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.
 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.
 public  void setDefaultCursor(Cursor cursor) 
    Sets the default cursor.
 public  void setLinkCursor(Cursor cursor) 
    Sets the cursor to use over links.
 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.
 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.