Java™ Platform
Standard Ed. 6

javax.swing.text.html
Class HTMLDocument.HTMLReader

java.lang.Object
  extended by javax.swing.text.html.HTMLEditorKit.ParserCallback
      extended by javax.swing.text.html.HTMLDocument.HTMLReader
Enclosing class:
HTMLDocument

public class HTMLDocument.HTMLReader
extends HTMLEditorKit.ParserCallback

An HTML reader to load an HTML document with an HTML element structure. This is a set of callbacks from the parser, implemented to create a set of elements tagged with attributes. The parse builds up tokens (ElementSpec) that describe the element subtree desired, and burst it into the document under the protection of a write lock using the insert method on the document outer class.

The reader can be configured by registering actions (of type HTMLDocument.HTMLReader.TagAction) that describe how to handle the action. The idea behind the actions provided is that the most natural text editing operations can be provided if the element structure boils down to paragraphs with runs of some kind of style in them. Some things are more naturally specified structurally, so arbitrary structure should be allowed above the paragraphs, but will need to be edited with structural actions. The implication of this is that some of the HTML elements specified in the stream being parsed will be collapsed into attributes, and in some cases paragraphs will be synthesized. When HTML elements have been converted to attributes, the attribute key will be of type HTML.Tag, and the value will be of type AttributeSet so that no information is lost. This enables many of the existing actions to work so that the user can type input, hit the return key, backspace, delete, etc and have a reasonable result. Selections can be created, and attributes applied or removed, etc. With this in mind, the work done by the reader can be categorized into the following kinds of tasks:

Block
Build the structure like it's specified in the stream. This produces elements that contain other elements.
Paragraph
Like block except that it's expected that the element will be used with a paragraph view so a paragraph element won't need to be synthesized.
Character
Contribute the element as an attribute that will start and stop at arbitrary text locations. This will ultimately be mixed into a run of text, with all of the currently flattened HTML character elements.
Special
Produce an embedded graphical element.
Form
Produce an element that is like the embedded graphical element, except that it also has a component model associated with it.
Hidden
Create an element that is hidden from view when the document is being viewed read-only, and visible when the document is being edited. This is useful to keep the model from losing information, and used to store things like comments and unrecognized tags.

Currently, <APPLET>, <PARAM>, <MAP>, <AREA>, <LINK>, <SCRIPT> and <STYLE> are unsupported.

The assignment of the actions described is shown in the following table for the tags defined in HTML.Tag.

TagAction
HTML.Tag.A CharacterAction
HTML.Tag.ADDRESS CharacterAction
HTML.Tag.APPLET HiddenAction
HTML.Tag.AREA AreaAction
HTML.Tag.B CharacterAction
HTML.Tag.BASE BaseAction
HTML.Tag.BASEFONT CharacterAction
HTML.Tag.BIG CharacterAction
HTML.Tag.BLOCKQUOTEBlockAction
HTML.Tag.BODY BlockAction
HTML.Tag.BR SpecialAction
HTML.Tag.CAPTION BlockAction
HTML.Tag.CENTER BlockAction
HTML.Tag.CITE CharacterAction
HTML.Tag.CODE CharacterAction
HTML.Tag.DD BlockAction
HTML.Tag.DFN CharacterAction
HTML.Tag.DIR BlockAction
HTML.Tag.DIV BlockAction
HTML.Tag.DL BlockAction
HTML.Tag.DT ParagraphAction
HTML.Tag.EM CharacterAction
HTML.Tag.FONT CharacterAction
HTML.Tag.FORM As of 1.4 a BlockAction
HTML.Tag.FRAME SpecialAction
HTML.Tag.FRAMESET BlockAction
HTML.Tag.H1 ParagraphAction
HTML.Tag.H2 ParagraphAction
HTML.Tag.H3 ParagraphAction
HTML.Tag.H4 ParagraphAction
HTML.Tag.H5 ParagraphAction
HTML.Tag.H6 ParagraphAction
HTML.Tag.HEAD HeadAction
HTML.Tag.HR SpecialAction
HTML.Tag.HTML BlockAction
HTML.Tag.I CharacterAction
HTML.Tag.IMG SpecialAction
HTML.Tag.INPUT FormAction
HTML.Tag.ISINDEX IsndexAction
HTML.Tag.KBD CharacterAction
HTML.Tag.LI BlockAction
HTML.Tag.LINK LinkAction
HTML.Tag.MAP MapAction
HTML.Tag.MENU BlockAction
HTML.Tag.META MetaAction
HTML.Tag.NOFRAMES BlockAction
HTML.Tag.OBJECT SpecialAction
HTML.Tag.OL BlockAction
HTML.Tag.OPTION FormAction
HTML.Tag.P ParagraphAction
HTML.Tag.PARAM HiddenAction
HTML.Tag.PRE PreAction
HTML.Tag.SAMP CharacterAction
HTML.Tag.SCRIPT HiddenAction
HTML.Tag.SELECT FormAction
HTML.Tag.SMALL CharacterAction
HTML.Tag.STRIKE CharacterAction
HTML.Tag.S CharacterAction
HTML.Tag.STRONG CharacterAction
HTML.Tag.STYLE StyleAction
HTML.Tag.SUB CharacterAction
HTML.Tag.SUP CharacterAction
HTML.Tag.TABLE BlockAction
HTML.Tag.TD BlockAction
HTML.Tag.TEXTAREA FormAction
HTML.Tag.TH BlockAction
HTML.Tag.TITLE TitleAction
HTML.Tag.TR BlockAction
HTML.Tag.TT CharacterAction
HTML.Tag.U CharacterAction
HTML.Tag.UL BlockAction
HTML.Tag.VAR CharacterAction

Once </html> is encountered, the Actions are no longer notified.


Nested Class Summary
 class HTMLDocument.HTMLReader.BlockAction
           
 class HTMLDocument.HTMLReader.CharacterAction
           
 class HTMLDocument.HTMLReader.FormAction
          Action to support forms by building all of the elements used to represent form controls.
 class HTMLDocument.HTMLReader.HiddenAction
           
 class HTMLDocument.HTMLReader.IsindexAction
           
 class HTMLDocument.HTMLReader.ParagraphAction
           
 class HTMLDocument.HTMLReader.PreAction
           
 class HTMLDocument.HTMLReader.SpecialAction
           
 class HTMLDocument.HTMLReader.TagAction
          An action to be performed in response to parsing a tag.
 
Field Summary
protected  MutableAttributeSet charAttr
           
protected  Vector<DefaultStyledDocument.ElementSpec> parseBuffer
           
 
Fields inherited from class javax.swing.text.html.HTMLEditorKit.ParserCallback
IMPLIED
 
Constructor Summary
HTMLDocument.HTMLReader(int offset)
           
HTMLDocument.HTMLReader(int offset, int popDepth, int pushDepth, HTML.Tag insertTag)
           
 
Method Summary
protected  void addContent(char[] data, int offs, int length)
          Adds some text with the current character attributes.
protected  void addContent(char[] data, int offs, int length, boolean generateImpliedPIfNecessary)
          Adds some text with the current character attributes.
protected  void addSpecialElement(HTML.Tag t, MutableAttributeSet a)
          Adds content that is basically specified entirely in the attribute set.
protected  void blockClose(HTML.Tag t)
          Adds an instruction to the parse buffer to close out a block element of the given type.
protected  void blockOpen(HTML.Tag t, MutableAttributeSet attr)
          Adds an instruction to the parse buffer to create a block element with the given attributes.
 void flush()
          The last method called on the reader.
 void handleComment(char[] data, int pos)
           
 void handleEndOfLineString(String eol)
          This is invoked after the stream has been parsed, but before flush.
 void handleEndTag(HTML.Tag t, int pos)
          Callback from the parser.
 void handleSimpleTag(HTML.Tag t, MutableAttributeSet a, int pos)
          Callback from the parser.
 void handleStartTag(HTML.Tag t, MutableAttributeSet a, int pos)
          Callback from the parser.
 void handleText(char[] data, int pos)
          Called by the parser to indicate a block of text was encountered.
protected  void popCharacterStyle()
          Pops a previously pushed character style off the stack to return to a previous style.
protected  void preContent(char[] data)
          Adds the given content that was encountered in a PRE element.
protected  void pushCharacterStyle()
          Pushes the current character style on a stack in preparation for forming a new nested character style.
protected  void registerTag(HTML.Tag t, HTMLDocument.HTMLReader.TagAction a)
          Registers a handler for the given tag.
protected  void textAreaContent(char[] data)
          Adds the given content to the textarea document.
 
Methods inherited from class javax.swing.text.html.HTMLEditorKit.ParserCallback
handleError
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

parseBuffer

protected Vector<DefaultStyledDocument.ElementSpec> parseBuffer

charAttr

protected MutableAttributeSet charAttr
Constructor Detail

HTMLDocument.HTMLReader

public HTMLDocument.HTMLReader(int offset)

HTMLDocument.HTMLReader

public HTMLDocument.HTMLReader(int offset,
                               int popDepth,
                               int pushDepth,
                               HTML.Tag insertTag)
Method Detail

flush

public void flush()
           throws BadLocationException
The last method called on the reader. It allows any pending changes to be flushed into the document. Since this is currently loading synchronously, the entire set of changes are pushed in at this point.

Overrides:
flush in class HTMLEditorKit.ParserCallback
Throws:
BadLocationException

handleText

public void handleText(char[] data,
                       int pos)
Called by the parser to indicate a block of text was encountered.

Overrides:
handleText in class HTMLEditorKit.ParserCallback

handleStartTag

public void handleStartTag(HTML.Tag t,
                           MutableAttributeSet a,
                           int pos)
Callback from the parser. Route to the appropriate handler for the tag.

Overrides:
handleStartTag in class HTMLEditorKit.ParserCallback

handleComment

public void handleComment(char[] data,
                          int pos)
Overrides:
handleComment in class HTMLEditorKit.ParserCallback

handleEndTag

public void handleEndTag(HTML.Tag t,
                         int pos)
Callback from the parser. Route to the appropriate handler for the tag.

Overrides:
handleEndTag in class HTMLEditorKit.ParserCallback

handleSimpleTag

public void handleSimpleTag(HTML.Tag t,
                            MutableAttributeSet a,
                            int pos)
Callback from the parser. Route to the appropriate handler for the tag.

Overrides:
handleSimpleTag in class HTMLEditorKit.ParserCallback

handleEndOfLineString

public void handleEndOfLineString(String eol)
This is invoked after the stream has been parsed, but before flush. eol will be one of \n, \r or \r\n, which ever is encountered the most in parsing the stream.

Overrides:
handleEndOfLineString in class HTMLEditorKit.ParserCallback
Since:
1.3

registerTag

protected void registerTag(HTML.Tag t,
                           HTMLDocument.HTMLReader.TagAction a)
Registers a handler for the given tag. By default all of the well-known tags will have been registered. This can be used to change the handling of a particular tag or to add support for custom tags.


pushCharacterStyle

protected void pushCharacterStyle()
Pushes the current character style on a stack in preparation for forming a new nested character style.


popCharacterStyle

protected void popCharacterStyle()
Pops a previously pushed character style off the stack to return to a previous style.


textAreaContent

protected void textAreaContent(char[] data)
Adds the given content to the textarea document. This method gets called when we are in a textarea context. Therefore all text that is seen belongs to the text area and is hence added to the TextAreaDocument associated with the text area.


preContent

protected void preContent(char[] data)
Adds the given content that was encountered in a PRE element. This synthesizes lines to hold the runs of text, and makes calls to addContent to actually add the text.


blockOpen

protected void blockOpen(HTML.Tag t,
                         MutableAttributeSet attr)
Adds an instruction to the parse buffer to create a block element with the given attributes.


blockClose

protected void blockClose(HTML.Tag t)
Adds an instruction to the parse buffer to close out a block element of the given type.


addContent

protected void addContent(char[] data,
                          int offs,
                          int length)
Adds some text with the current character attributes.

Parameters:
data - the content to add
offs - the initial offset
length - the length

addContent

protected void addContent(char[] data,
                          int offs,
                          int length,
                          boolean generateImpliedPIfNecessary)
Adds some text with the current character attributes.

Parameters:
data - the content to add
offs - the initial offset
length - the length
generateImpliedPIfNecessary - whether to generate implied paragraphs

addSpecialElement

protected void addSpecialElement(HTML.Tag t,
                                 MutableAttributeSet a)
Adds content that is basically specified entirely in the attribute set.


Java™ Platform
Standard Ed. 6

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