edu.harvard.hul.ois.jhove.module

Class HtmlModule

java.lang.Object

edu.harvard.hul.ois.jhove.ModuleBase

edu.harvard.hul.ois.jhove.module.HtmlModule

All Implemented Interfaces:

Module

public class HtmlModule
extends ModuleBase

Module for identification and validation of HTML files. HTML is different from most of the other documents in that sloppy construction is practically assumed in the specification. This module attempt to report as many errors as possible and recover reasonably from errors. To do this, there is more heuristic behavior built into this module than into the more straightforward ones. XHTML is recognized by this module, but is handed off to the XML module for processing. If the XML module is missing (which it shouldn't be if you've installed the JHOVE application without modifications), this won't be able to deal with XHTML files. HTML should be placed ahead of XML in the module order. If the XML module sees an XHTML file first, it will recognize it as XHTML, but won't be able to report the complete properties. The HTML module uses code created with the JavaCC parser generator and lexical analyzer generator. There is apparently a bug in JavaCC which causes blank lines not to be counted in certain cases, causing lexical errors to be reported with incorrect line numbers.

Author:

Gary McGath

Field Summary

Fields

Modifier and Type	Field and Description
protected ChecksumInputStream	_cstream PRIVATE INSTANCE FIELDS.
protected String	_doctype
protected DataInputStream	_dstream
protected TextMDMetadata	_textMD
protected boolean	_withTextMD
static int	HTML_3_2
static int	HTML_4_0_FRAMESET
static int	HTML_4_0_STRICT
static int	HTML_4_0_TRANSITIONAL
static int	HTML_4_01_FRAMESET
static int	HTML_4_01_STRICT
static int	HTML_4_01_TRANSITIONAL
static int	XHTML_1_0_FRAMESET
static int	XHTML_1_0_STRICT
static int	XHTML_1_0_TRANSITIONAL
static int	XHTML_1_1

Fields inherited from class edu.harvard.hul.ois.jhove.ModuleBase

_app, _bigEndian, _checksumFinished, _countStream, _coverage, _crc32, _date, _defaultParams, _features, _format, _init, _isRandomAccess, _je, _logger, _md5, _mimeType, _name, _nByte, _note, _param, _release, _repInfoNote, _rights, _sha1, _signature, _specification, _validityNote, _vendor, _verbosity, _wellFormedNote

Fields inherited from interface edu.harvard.hul.ois.jhove.Module

MAXIMUM_VERBOSITY, MINIMUM_VERBOSITY

Constructor Summary

Constructors

Constructor and Description
HtmlModule() Instantiate an HtmlModule object.

Method Summary

Modifier and Type	Method and Description
protected int	checkDoctype(List elements)
void	checkSignatures(File file, InputStream stream, RepInfo info) Check if the digital object conforms to this Module's internal signature information.
protected static boolean	isXmlAvailable()
int	parse(InputStream stream, RepInfo info, int parseIndex) Parse the content of a purported HTML stream digital object and store the results in RepInfo.
protected int	seemsToBeXHTML(List elements)
protected String	stripQuotes(String str)

Methods inherited from class edu.harvard.hul.ois.jhove.ModuleBase

addIntegerProperty, addIntegerProperty, applyDefaultParams, calcRAChecksum, checkSignatures, getApp, getBase, getBufferedDataStream, getCoverage, getCRC32, getDate, getDefaultParams, getFeatures, getFormat, getMimeType, getName, getNByte, getNote, getRelease, getRepInfoNote, getRights, getSignature, getSpecification, getValidityNote, getVendor, getWellFormedNote, hasFeature, init, initFeatures, initParse, isBigEndian, isRandomAccess, param, parse, readByteBuf, readDouble, readDouble, readDouble, readFloat, readFloat, readSignedByte, readSignedByte, readSignedByte, readSignedInt, readSignedInt, readSignedInt, readSignedLong, readSignedRational, readSignedRational, readSignedShort, readSignedShort, readSignedShort, readUnsignedByte, readUnsignedByte, readUnsignedByte, readUnsignedInt, readUnsignedInt, readUnsignedInt, readUnsignedRational, readUnsignedRational, readUnsignedRational, readUnsignedShort, readUnsignedShort, readUnsignedShort, resetParams, setApp, setBase, setChecksums, setCRC32, setDefaultParams, setMD5, setNByte, setSHA1, setValidityNote, setVerbosity, show, skipBytes, skipBytes, vectorToPropArray

Methods inherited from class java.lang.Object

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

Field Detail

_cstream

protected ChecksumInputStream _cstream

PRIVATE INSTANCE FIELDS.

_dstream

protected DataInputStream _dstream

_doctype

protected String _doctype

HTML_3_2

public static final int HTML_3_2

See Also:

Constant Field Values

HTML_4_0_STRICT

public static final int HTML_4_0_STRICT

See Also:

Constant Field Values

HTML_4_0_FRAMESET

public static final int HTML_4_0_FRAMESET

See Also:

Constant Field Values

HTML_4_0_TRANSITIONAL

public static final int HTML_4_0_TRANSITIONAL

See Also:

Constant Field Values

HTML_4_01_STRICT

public static final int HTML_4_01_STRICT

See Also:

Constant Field Values

HTML_4_01_FRAMESET

public static final int HTML_4_01_FRAMESET

See Also:

Constant Field Values

HTML_4_01_TRANSITIONAL

public static final int HTML_4_01_TRANSITIONAL

See Also:

Constant Field Values

XHTML_1_0_STRICT

public static final int XHTML_1_0_STRICT

See Also:

Constant Field Values

XHTML_1_0_TRANSITIONAL

public static final int XHTML_1_0_TRANSITIONAL

See Also:

Constant Field Values

XHTML_1_0_FRAMESET

public static final int XHTML_1_0_FRAMESET

See Also:

Constant Field Values

XHTML_1_1

public static final int XHTML_1_1

See Also:

Constant Field Values

_withTextMD

protected boolean _withTextMD

_textMD

protected TextMDMetadata _textMD

Constructor Detail

HtmlModule

public HtmlModule()

Instantiate an HtmlModule object.

Method Detail

parse

public int parse(InputStream stream,
                 RepInfo info,
                 int parseIndex)
          throws IOException

Parse the content of a purported HTML stream digital object and store the results in RepInfo.

Specified by:

parse in interface Module

Overrides:

parse in class ModuleBase

Parameters:

stream - An InputStream, positioned at its beginning, which is generated from the object to be parsed. If multiple calls to parse are made on the basis of a nonzero value being returned, a new InputStream must be provided each time.

info - A fresh (on the first call) RepInfo object which will be modified to reflect the results of the parsing If multiple calls to parse are made on the basis of a nonzero value being returned, the same RepInfo object should be passed with each call.

parseIndex - Must be 0 in first call to parse. If parse returns a nonzero value, it must be called again with parseIndex equal to that return value.

Throws:

IOException

checkSignatures

public void checkSignatures(File file,
                            InputStream stream,
                            RepInfo info)
                     throws IOException

Check if the digital object conforms to this Module's internal signature information. HTML is one of the most ill-defined of any open formats, so checking a "signature" really means using some heuristics. The only required tag is TITLE, but that could occur well into the file. So we look for any of three strings -- taking into account case-independence and white space -- within the first sigBytes bytes, and call that a signature check.

Specified by:

checkSignatures in interface Module

Overrides:

checkSignatures in class ModuleBase

Parameters:

file - A File object for the object being parsed

stream - An InputStream, positioned at its beginning, which is generated from the object to be parsed

info - A fresh RepInfo object which will be modified to reflect the results of the test

Throws:

IOException

checkDoctype

protected int checkDoctype(List elements)

seemsToBeXHTML

protected int seemsToBeXHTML(List elements)

stripQuotes

protected String stripQuotes(String str)

isXmlAvailable

protected static boolean isXmlAvailable()