Module java.desktop

Package javax.swing.text.html

Class HTMLDocument.HTMLReader

java.lang.Object

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