javax.swing.text.html.parser
Class Parser

java.lang.Object
  javax.swing.text.html.parser.Parser

All Implemented Interfaces:

DTDConstants

Direct Known Subclasses:

DocumentParser

public class Parser

extends Object

implements DTDConstants

A simple DTD-driven HTML parser. The parser reads an HTML file from an InputStream and calls various methods (which should be overridden in a subclass) when tags and data are encountered.

Unfortunately there are many badly implemented HTML parsers out there, and as a result there are many badly formatted HTML files. This parser attempts to parse most HTML files. This means that the implementation sometimes deviates from the SGML specification in favor of HTML.

The parser treats \r and \r\n as \n. Newlines after starttags and before end tags are ignored just as specified in the SGML/HTML specification.

The html spec does not specify how spaces are to be coalesced very well. Specifically, the following scenarios are not discussed (note that a space should be used here, but I am using &nbsp to force the space to be displayed):

'<b>blah <i> <strike> foo' which can be treated as: '<b>blah <i><strike>foo'

as well as: '<p><a href="xx"> <em>Using</em></a></p>' which appears to be treated as: '<p><a href="xx"><em>Using</em></a></p>'

If strict is false, when a tag that breaks flow, (TagElement.breaksFlows) or trailing whitespace is encountered, all whitespace will be ignored until a non whitespace character is encountered. This appears to give behavior closer to the popular browsers.

Author:

Arthur van Hoff, Sunita Mani

See Also:

DTD, TagElement, SimpleAttributeSet

Field Summary

private SimpleAttributeSet	attributes
private char[]	buf
private int	ch
private int	crCount Number of \r's encountered.
private int	crlfCount Number of \r\n's encountered.
private int	currentBlockStartPos The start position of the current block.
private int	currentPosition
protected DTD	dtd
private boolean	ignoreSpace The html spec does not specify how spaces are coalesced very well.
private Reader	in
private TagElement	last
private int	lastBlockStartPos Start position of the last block.
private TagElement	lastFormSent
private int	len
private int	lfCount Number of \n's encountered.
private int	ln
private int	pos
private Element	recent
private boolean	seenBody
private boolean	seenHead
private boolean	seenHtml
private boolean	skipTag
private boolean	space
private TagStack	stack
private char[]	str
protected boolean	strict This flag determines whether or not the Parser will be strict in enforcing SGML compatibility.
private int	strpos
private char[]	text
private int	textpos

Fields inherited from interface javax.swing.text.html.parser.DTDConstants

ANY, CDATA, CONREF, CURRENT, DEFAULT, EMPTY, ENDTAG, ENTITIES, ENTITY, FIXED, GENERAL, ID, IDREF, IDREFS, IMPLIED, MD, MODEL, MS, NAME, NAMES, NMTOKEN, NMTOKENS, NOTATION, NUMBER, NUMBERS, NUTOKEN, NUTOKENS, PARAMETER, PI, PUBLIC, RCDATA, REQUIRED, SDATA, STARTTAG, SYSTEM

Constructor Summary

Parser(DTD dtd)

Method Summary

(package private) void	addString(int c) Add a char to the string buffer.
protected void	endTag(boolean omitted) Handle an end tag.
protected void	error(String err)
protected void	error(String err, String arg1)
protected void	error(String err, String arg1, String arg2)
protected void	error(String err, String arg1, String arg2, String arg3) Invoke the error handler.
(package private) void	errorContext() Error context.
protected void	flushAttributes()
protected SimpleAttributeSet	getAttributes()
(package private) int	getBlockStartPosition() Returns the start position of the current block.
(package private) char[]	getChars(int pos)
(package private) char[]	getChars(int pos, int endPos)
protected int	getCurrentLine()
protected int	getCurrentPos()
(package private) String	getEndOfLineString() Returns the end of line string.
(package private) String	getString(int pos) Get the string that's been accumulated.
protected void	handleComment(char[] text) Called when an HTML comment is encountered.
protected void	handleEmptyTag(TagElement tag) Called when an empty tag is encountered.
protected void	handleEndTag(TagElement tag) Called when an end tag is encountered.
protected void	handleEOFInComment()
protected void	handleError(int ln, String msg) An error has occurred.
protected void	handleStartTag(TagElement tag) Called when a start tag is encountered.
protected void	handleText(char[] text) Called when PCDATA is encountered.
(package private) void	handleText(TagElement tag) Output text.
protected void	handleTitle(char[] text) Called when an HTML title tag is encountered.
(package private) boolean	ignoreElement(Element elem)
(package private) boolean	legalElementContext(Element elem) Create a legal content for an element.
(package private) void	legalTagContext(TagElement tag) Create a legal context for a tag.
protected TagElement	makeTag(Element elem)
protected TagElement	makeTag(Element elem, boolean fictional) Makes a TagElement.
protected void	markFirstTime(Element elem) Marks the first time a tag has been seen in a document
void	parse(Reader in) Parse an HTML stream, given a DTD.
(package private) void	parseAttributeSpecificationList(Element elem) Parse attribute specification List. [31] 327:17
(package private) String	parseAttributeValue(boolean lower) Parse attribute value. [33] 331:1
(package private) void	parseComment() Parse a comment. [92] 391:7
(package private) void	parseContent() Parse Content. [24] 320:1
String	parseDTDMarkup() Parses th Document Declaration Type markup declaration.
private char[]	parseEntityReference() Parse an entity reference. [59] 350:17
(package private) boolean	parseIdentifier(boolean lower) Parse identifier.
(package private) void	parseInvalidTag() Parse an invalid tag.
(package private) void	parseLiteral(boolean replace) Parse literal content. [46] 343:1 and [47] 344:1
protected boolean	parseMarkupDeclarations(StringBuffer strBuff) Parse markup declarations.
(package private) void	parseTag() Parse a start or end tag.
private int	readCh()
(package private) void	resetStrBuffer()
(package private) void	skipSpace() Skip space
protected void	startTag(TagElement tag) Handle a start tag.
(package private) int	strIndexOf(char target)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

text

private char[] text

textpos

private int textpos

last

private TagElement last

space

private boolean space

str

private char[] str

strpos

private int strpos

dtd

protected DTD dtd

ch

private int ch

ln

private int ln

in

private Reader in

recent

private Element recent

stack

private TagStack stack

skipTag

private boolean skipTag

lastFormSent

private TagElement lastFormSent

attributes

private SimpleAttributeSet attributes

seenHtml

private boolean seenHtml

seenHead

private boolean seenHead

seenBody

private boolean seenBody

ignoreSpace

private boolean ignoreSpace

The html spec does not specify how spaces are coalesced very well. If strict == false, ignoreSpace is used to try and mimic the behavior of the popular browsers.

The problematic scenarios are: '<b>blah <i> <strike> foo' which can be treated as: '<b>blah <i><strike>foo' as well as: '<p><a href="xx"> <em>Using</em></a></p>' which appears to be treated as: '<p><a href="xx"><em>Using</em></a></p>'

When a tag that breaks flow, or trailing whitespace is encountered ignoreSpace is set to true. From then on, all whitespace will be ignored. ignoreSpace will be set back to false the first time a non whitespace character is encountered. This appears to give behavior closer to the popular browsers.

strict

protected boolean strict

This flag determines whether or not the Parser will be strict in enforcing SGML compatibility. If false, it will be lenient with certain common classes of erroneous HTML constructs. Strict or not, in either case an error will be recorded.

crlfCount

private int crlfCount

Number of \r\n's encountered.

crCount

private int crCount

Number of \r's encountered. A \r\n will not increment this.

lfCount

private int lfCount

Number of \n's encountered. A \r\n will not increment this.

currentBlockStartPos

private int currentBlockStartPos

The start position of the current block. Block is overloaded here, it really means the current start position for the current comment, tag, text. Use getBlockStartPosition to access this.

lastBlockStartPos

private int lastBlockStartPos

Start position of the last block.

buf

private char[] buf

pos

private int pos

len

private int len

currentPosition

private int currentPosition

Constructor Detail

Parser

public Parser(DTD dtd)

Method Detail

getCurrentLine

protected int getCurrentLine()

Returns:

the line number of the line currently being parsed

getBlockStartPosition

int getBlockStartPosition()

Returns the start position of the current block. Block is overloaded here, it really means the current start position for the current comment tag, text, block.... This is provided for subclassers that wish to know the start of the current block when called with one of the handleXXX methods.

makeTag

protected TagElement makeTag(Element elem,
                             boolean fictional)

Makes a TagElement.

makeTag

protected TagElement makeTag(Element elem)

getAttributes

protected SimpleAttributeSet getAttributes()

flushAttributes

protected void flushAttributes()

handleText

protected void handleText(char[] text)

Called when PCDATA is encountered.

handleTitle

protected void handleTitle(char[] text)

Called when an HTML title tag is encountered.

handleComment

protected void handleComment(char[] text)

Called when an HTML comment is encountered.

handleEOFInComment

protected void handleEOFInComment()

handleEmptyTag

protected void handleEmptyTag(TagElement tag)
                       throws ChangedCharSetException

Called when an empty tag is encountered.

Throws:

ChangedCharSetException

handleStartTag

protected void handleStartTag(TagElement tag)

Called when a start tag is encountered.

handleEndTag

protected void handleEndTag(TagElement tag)

Called when an end tag is encountered.

handleError

protected void handleError(int ln,
                           String msg)

An error has occurred.

handleText

void handleText(TagElement tag)

Output text.

error

protected void error(String err,
                     String arg1,
                     String arg2,
                     String arg3)

Invoke the error handler.

error

protected void error(String err,
                     String arg1,
                     String arg2)

error

protected void error(String err,
                     String arg1)

error

protected void error(String err)

startTag

protected void startTag(TagElement tag)
                 throws ChangedCharSetException

Handle a start tag. The new tag is pushed onto the tag stack. The attribute list is checked for required attributes.

Throws:

ChangedCharSetException

endTag

protected void endTag(boolean omitted)

Handle an end tag. The end tag is popped from the tag stack.

ignoreElement

boolean ignoreElement(Element elem)

markFirstTime

protected void markFirstTime(Element elem)

Marks the first time a tag has been seen in a document

legalElementContext

boolean legalElementContext(Element elem)
                      throws ChangedCharSetException

Create a legal content for an element.

Throws:

ChangedCharSetException

legalTagContext

void legalTagContext(TagElement tag)
               throws ChangedCharSetException

Create a legal context for a tag.

Throws:

ChangedCharSetException

errorContext

void errorContext()
            throws ChangedCharSetException

Error context. Something went wrong, make sure we are in the document's body context

Throws:

ChangedCharSetException

addString

void addString(int c)

Add a char to the string buffer.

getString

String getString(int pos)

Get the string that's been accumulated.

getChars

char[] getChars(int pos)

getChars

char[] getChars(int pos,
                int endPos)

resetStrBuffer

void resetStrBuffer()

strIndexOf

int strIndexOf(char target)

skipSpace

void skipSpace()
         throws IOException

Skip space. [5] 297:5

Throws:

IOException

parseIdentifier

boolean parseIdentifier(boolean lower)
                  throws IOException

Parse identifier. Uppercase characters are folded to lowercase when lower is true. Returns falsed if no identifier is found. [55] 346:17

Throws:

IOException

parseEntityReference

private char[] parseEntityReference()
                             throws IOException

Parse an entity reference. [59] 350:17

Throws:

IOException

parseComment

void parseComment()
            throws IOException

Parse a comment. [92] 391:7

Throws:

IOException

parseLiteral

void parseLiteral(boolean replace)
            throws IOException

Parse literal content. [46] 343:1 and [47] 344:1

Throws:

IOException

parseAttributeValue

String parseAttributeValue(boolean lower)
                     throws IOException

Parse attribute value. [33] 331:1

Throws:

IOException

parseAttributeSpecificationList

void parseAttributeSpecificationList(Element elem)
                               throws IOException

Parse attribute specification List. [31] 327:17

Throws:

IOException

parseDTDMarkup

public String parseDTDMarkup()
                      throws IOException

Parses th Document Declaration Type markup declaration. Currently ignores it.

Throws:

IOException

parseMarkupDeclarations

protected boolean parseMarkupDeclarations(StringBuffer strBuff)
                                   throws IOException

Parse markup declarations. Currently only handles the Document Type Declaration markup. Returns true if it is a markup declaration false otherwise.

Throws:

IOException

parseInvalidTag

void parseInvalidTag()
               throws IOException

Parse an invalid tag.

Throws:

IOException

parseTag

void parseTag()
        throws IOException

Parse a start or end tag.

Throws:

IOException

parseContent

void parseContent()
            throws IOException

Parse Content. [24] 320:1

Throws:

IOException

getEndOfLineString

String getEndOfLineString()

Returns the end of line string. This will return the end of line string that has been encountered the most, one of \r, \n or \r\n.

parse

public void parse(Reader in)
           throws IOException

Parse an HTML stream, given a DTD.

Throws:

IOException

readCh

private final int readCh()
                  throws IOException

Throws:

IOException

getCurrentPos

protected int getCurrentPos()