- java.lang.Object
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- javax.swing.text.html.parser.Parser
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- 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   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
strictis 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.- See Also:
DTD,TagElement,SimpleAttributeSet
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Field Summary
Fields Modifier and Type Field Description protected DTDdtdThe dtd.protected booleanstrictThis flag determines whether or not the Parser will be strict in enforcing SGML compatibility.-
Fields declared in 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
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected voidendTag(boolean omitted)Handle an end tag.protected voiderror(String err)Invokes the error handler with the 1st, 2nd and 3rd error message argument "?".protected voiderror(String err, String arg1)Invokes the error handler with the 2nd and 3rd error message argument "?".protected voiderror(String err, String arg1, String arg2)Invokes the error handler with the 3rd error message argument "?".protected voiderror(String err, String arg1, String arg2, String arg3)Invokes the error handler.protected voidflushAttributes()Removes the current attributes.protected SimpleAttributeSetgetAttributes()Returns attributes for the current tag.protected intgetCurrentLine()protected intgetCurrentPos()Returns the current position.protected voidhandleComment(char[] text)Called when an HTML comment is encountered.protected voidhandleEmptyTag(TagElement tag)Called when an empty tag is encountered.protected voidhandleEndTag(TagElement tag)Called when an end tag is encountered.protected voidhandleEOFInComment()Called when the content terminates without closing the HTML comment.protected voidhandleError(int ln, String msg)An error has occurred.protected voidhandleStartTag(TagElement tag)Called when a start tag is encountered.protected voidhandleText(char[] text)Called when PCDATA is encountered.protected voidhandleTitle(char[] text)Called when an HTML title tag is encountered.protected TagElementmakeTag(Element elem)Makes a TagElement.protected TagElementmakeTag(Element elem, boolean fictional)Makes a TagElement.protected voidmarkFirstTime(Element elem)Marks the first time a tag has been seen in a documentvoidparse(Reader in)Parse an HTML stream, given a DTD.StringparseDTDMarkup()Parses the Document Type Declaration markup declaration.protected booleanparseMarkupDeclarations(StringBuffer strBuff)Parse markup declarations.protected voidstartTag(TagElement tag)Handle a start tag.
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Field Detail
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dtd
protected DTD dtd
The dtd.
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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.
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Constructor Detail
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Parser
public Parser(DTD dtd)
Creates parser with the specifieddtd.- Parameters:
dtd- the dtd.
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Method Detail
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getCurrentLine
protected int getCurrentLine()
- Returns:
- the line number of the line currently being parsed
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makeTag
protected TagElement makeTag(Element elem, boolean fictional)
Makes a TagElement.- Parameters:
elem- the element storing the tag definitionfictional- the value of the flag "fictional" to be set for the tag- Returns:
- the created
TagElement
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makeTag
protected TagElement makeTag(Element elem)
Makes a TagElement.- Parameters:
elem- the element storing the tag definition- Returns:
- the created
TagElement
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getAttributes
protected SimpleAttributeSet getAttributes()
Returns attributes for the current tag.- Returns:
SimpleAttributeSetcontaining the attributes
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flushAttributes
protected void flushAttributes()
Removes the current attributes.
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handleText
protected void handleText(char[] text)
Called when PCDATA is encountered.- Parameters:
text- the section text
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handleTitle
protected void handleTitle(char[] text)
Called when an HTML title tag is encountered.- Parameters:
text- the title text
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handleComment
protected void handleComment(char[] text)
Called when an HTML comment is encountered.- Parameters:
text- the comment being handled
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handleEOFInComment
protected void handleEOFInComment()
Called when the content terminates without closing the HTML comment.
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handleEmptyTag
protected void handleEmptyTag(TagElement tag) throws ChangedCharSetException
Called when an empty tag is encountered.- Parameters:
tag- the tag being handled- Throws:
ChangedCharSetException- if the document charset was changed
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handleStartTag
protected void handleStartTag(TagElement tag)
Called when a start tag is encountered.- Parameters:
tag- the tag being handled
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handleEndTag
protected void handleEndTag(TagElement tag)
Called when an end tag is encountered.- Parameters:
tag- the tag being handled
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handleError
protected void handleError(int ln, String msg)An error has occurred.- Parameters:
ln- the number of line containing the errormsg- the error message
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error
protected void error(String err, String arg1, String arg2, String arg3)
Invokes the error handler.- Parameters:
err- the error typearg1- the 1st error message argumentarg2- the 2nd error message argumentarg3- the 3rd error message argument
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error
protected void error(String err, String arg1, String arg2)
Invokes the error handler with the 3rd error message argument "?".- Parameters:
err- the error typearg1- the 1st error message argumentarg2- the 2nd error message argument
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error
protected void error(String err, String arg1)
Invokes the error handler with the 2nd and 3rd error message argument "?".- Parameters:
err- the error typearg1- the 1st error message argument
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error
protected void error(String err)
Invokes the error handler with the 1st, 2nd and 3rd error message argument "?".- Parameters:
err- the error type
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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.- Parameters:
tag- the tag- Throws:
ChangedCharSetException- if the document charset was changed
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endTag
protected void endTag(boolean omitted)
Handle an end tag. The end tag is popped from the tag stack.- Parameters:
omitted-trueif the tag is no actually present in the document, but is supposed by the parser
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markFirstTime
protected void markFirstTime(Element elem)
Marks the first time a tag has been seen in a document- Parameters:
elem- the element represented by the tag
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parseDTDMarkup
public String parseDTDMarkup() throws IOException
Parses the Document Type Declaration markup declaration. Currently ignores it.- Returns:
- the string representation of the markup declaration
- Throws:
IOException- if an I/O error occurs
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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.- Parameters:
strBuff- the markup declaration- Returns:
trueif this is a valid markup declaration; otherwisefalse- Throws:
IOException- if an I/O error occurs
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parse
public void parse(Reader in) throws IOException
Parse an HTML stream, given a DTD.- Parameters:
in- the reader to read the source from- Throws:
IOException- if an I/O error occurs
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getCurrentPos
protected int getCurrentPos()
Returns the current position.- Returns:
- the current position
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