javax.swing.text.html.HTMLEditorKit.ParserCallback

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.

HTML tags and assigned actions
Tag	Action
`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.BLOCKQUOTE`	BlockAction
`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

Nested Classes

Modifier and Type

Class

Description

class

HTMLDocument.HTMLReader.BlockAction

Action assigned by default to handle the Block task of the reader.

class

HTMLDocument.HTMLReader.CharacterAction

Action assigned by default to handle the Character task of the reader.

class

HTMLDocument.HTMLReader.FormAction

Action to support forms by building all of the elements used to represent form controls.

class

HTMLDocument.HTMLReader.HiddenAction

Action assigned by default to handle the Hidden task of the reader.

class

HTMLDocument.HTMLReader.IsindexAction

Action assigned by default to handle the Isindex task of the reader.

class

HTMLDocument.HTMLReader.ParagraphAction

Action assigned by default to handle the Paragraph task of the reader.

class

HTMLDocument.HTMLReader.PreAction

Action assigned by default to handle the Pre block task of the reader.

class

HTMLDocument.HTMLReader.SpecialAction

Action assigned by default to handle the Special task of the reader.

class

HTMLDocument.HTMLReader.TagAction

An action to be performed in response to parsing a tag.
Field Summary

Fields

Modifier and Type

Field

Description

protected MutableAttributeSet

charAttr

Current character attribute set.

protected Vector<DefaultStyledDocument.ElementSpec>

parseBuffer

Buffer to keep building elements.

Fields declared in class javax.swing.text.html.HTMLEditorKit.ParserCallback
IMPLIED
Constructor Summary

Constructors

Constructor

Description

HTMLReader(int offset)

Constructs an HTMLReader using default pop and push depth and no tag to insert.

HTMLReader(int offset, int popDepth, int pushDepth, HTML.Tag insertTag)

Constructs an HTMLReader.
Method Summary

Modifier and Type

Method

Description

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

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 declared in class javax.swing.text.html.HTMLEditorKit.ParserCallback
handleComment, handleError

Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details
- parseBuffer
  
  protected Vector<DefaultStyledDocument.ElementSpec> parseBuffer
  
  Buffer to keep building elements.
- charAttr
  
  protected MutableAttributeSet charAttr
  
  Current character attribute set.
Constructor Details
- HTMLReader
  
  public HTMLReader(int offset)
  
  Constructs an HTMLReader using default pop and push depth and no tag to insert.
  
  Parameters:
  
  offset - the starting offset
- HTMLReader
  
  public HTMLReader(int offset, int popDepth, int pushDepth, HTML.Tag insertTag)
  
  Constructs an HTMLReader.
  
  Parameters:
  
  offset - the starting offset
  
  popDepth - how many parents to ascend before insert new element
  
  pushDepth - how many parents to descend (relative to popDepth) before inserting
  
  insertTag - a tag to insert (may be null)
Method Details
- 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 - if the given position does not represent a valid location in the associated document.
- 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
  
  Parameters:
  
  data - a data
  
  pos - a position
- 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
  
  Parameters:
  
  t - an HTML tag
  
  a - a set of attributes
  
  pos - a position
- 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
  
  Parameters:
  
  t - an HTML tag
  
  pos - a position
- 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
  
  Parameters:
  
  t - an HTML tag
  
  a - a set of attributes
  
  pos - a position
- 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
  
  Parameters:
  
  eol - value of eol
  
  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.
  
  Parameters:
  
  t - an HTML tag
  
  a - tag action handler
- 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.
  
  Parameters:
  
  data - the given content
- 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.
  
  Parameters:
  
  data - the given content
- 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.
  
  Parameters:
  
  t - an HTML tag
  
  attr - the attribute set
- blockClose
  
  protected void blockClose(HTML.Tag t)
  
  Adds an instruction to the parse buffer to close out a block element of the given type.
  
  Parameters:
  
  t - the HTML tag
- 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.
  
  Parameters:
  
  t - an HTML tag
  
  a - the attribute set

Class HTMLDocument.HTMLReader

Nested Class Summary

Field Summary

Fields declared in class javax.swing.text.html.HTMLEditorKit.ParserCallback

Constructor Summary

Method Summary

Methods declared in class javax.swing.text.html.HTMLEditorKit.ParserCallback

Methods declared in class java.lang.Object

Field Details

parseBuffer

charAttr

Constructor Details

HTMLReader

HTMLReader

Method Details

flush

handleText

handleStartTag

handleEndTag

handleSimpleTag

handleEndOfLineString

registerTag

pushCharacterStyle

popCharacterStyle

textAreaContent

preContent

blockOpen

blockClose

addContent

addContent

addSpecialElement