org.dlese.dpc.xml
Class XMLConversionService

java.lang.Object
  org.dlese.dpc.xml.XMLConversionService

public final class XMLConversionService
extends Object

Manages the conversion of XML files from one format to another using XSL or Java classes. Caches the converted XML to disc and provides rapid access to the converted format. Conversions may be accomplished using XSL stylesheets or Java classes that implement one of either the XMLFormatConverter or XMLDocumentFormatConverter interfaces.

Version:

$Id: XMLConversionService.java,v 1.24 2007/02/23 21:20:00 jweather Exp $

Author:

John Weatherley

See Also:

XMLFormatConverter, XMLDocumentFormatConverter

Constructor Summary

XMLConversionService(File cacheDir, boolean filterDeclarations)
Constructor for the XMLConversionService.

Method Summary

void	addJavaConverterClass(String fromFormat, String toFormat, String className, ServletContext servletContext) Adds a concrete implementation of the XMLFormatConverter interface that can convert XML from one format to another.
boolean	addJavaConverterHelper(String paramVal, ServletContext servletContext) Adds an Java class XML converter by parsing a String of the form [ fromFormat | toFormat | className ].
boolean	addXslConverterHelper(String paramVal, File xslFilesDirecoryPath) Adds an XSL converter by parsing a String of the form [ fromFormat | toFormat | xslFileName ].
void	addXslStylesheet(String fromFormat, String toFormat, String xslFilePath) Adds a XSL stylesheet that can convert from one XML format to another.
boolean	canConvert(String fromFormat, String toFormat) Determines whether this XMLConversionService can perform the given converstion.
String	convertXml(String fromFormat, String toFormat, String originalXML) Converts XML from one format to another, without the use of a cache to store or save results.
ArrayList	getAvailableFormats(String fromFormat) Gets the metadata format conversions that are available for the given format, including the given format.
static String	getContentFromXML(String input) Gets the content from XML by stripping all XML tags.
StringBuffer	getConvertedXml(String fromFormat, String toFormat, File originalXMLFile) Converts XML from one format to another, saving and retrieving the converted content to and from a file cache.
StringBuffer	getConvertedXml(String fromFormat, String toFormat, File originalXMLFile, XMLDocReader luceneDoc) Converts XML from one format to another, saving and retrieving the converted content to and from a file cache.
static String	getDateStamp() Gets a datestamp of the current time formatted for display with logs and output.
static void	setDebug(boolean db) Sets the debug attribute of the SimpleLuceneIndex object
static StringBuffer	stripXmlDeclaration(BufferedReader rdr) Strips the XML declaration and DTD declaration from the given XML.
static XMLConversionService	xmlConversionServiceFactoryForServlets(ServletContext servletContext, File xslFilesDirecory, File xmlCachDirecory, boolean filterDeclarations) Factory for use in Servlets to create an XMLConversionService using configurations found in the Servlet context parameters.

Methods inherited from class java.lang.Object

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

Constructor Detail

XMLConversionService

public XMLConversionService(File cacheDir,
                            boolean filterDeclarations)
                     throws IOException

Constructor for the XMLConversionService.

Parameters:

cacheDir - The directory where converted files will be cached and stored for later retrieval by ID.

filterDeclarations - Set to true to filter out the XML and DTD declarations in the converted XML.

Throws:

IOException - If the directory is not valid or does not have read/write access.

Method Detail

getConvertedXml

public StringBuffer getConvertedXml(String fromFormat,
                                    String toFormat,
                                    File originalXMLFile)

Converts XML from one format to another, saving and retrieving the converted content to and from a file cache. Returns null if there are no known conversions available for the requested conversion, or if a processing error occurs. The cache file is automatically updated if the modification time of the input XML file is newer than the cache. Characters returned in the StringBuffer are encoded in UTF-8.

Parameters:

fromFormat - The XML format to convert from. Example: 'dlese_ims.'

toFormat - The format to convert to. Example: 'adn.'

originalXMLFile - The original XML file, in the 'from' format.

Returns:

Content converted to the 'to' format, or null if unable to process.

convertXml

public String convertXml(String fromFormat,
                         String toFormat,
                         String originalXML)

Converts XML from one format to another, without the use of a cache to store or save results. Returns null if there are no known conversions available for the requested conversion, or if a processing error occurs. Characters returned in the StringBuffer are encoded in UTF-8.

Parameters:

fromFormat - The XML format to convert from. Example: 'dlese_ims.'

toFormat - The format to convert to. Example: 'adn.'

originalXML - The original XML as a String, in the 'from' format. Should not be null.

Returns:

Content converted to the 'to' format, or null if unable to process.

getConvertedXml

public StringBuffer getConvertedXml(String fromFormat,
                                    String toFormat,
                                    File originalXMLFile,
                                    XMLDocReader luceneDoc)

Converts XML from one format to another, saving and retrieving the converted content to and from a file cache. Returns null if there are no known conversions available for the requested conversion, or if a processing error occurs. The cache file is automatically updated if the modification time of the input XML file is newer than the cache. Characters returned in the StringBuffer are encoded in UTF-8.

Parameters:

fromFormat - The XML format to convert from. Example: 'dlese_ims.'

toFormat - The format to convert to. Example: 'adn.'

originalXMLFile - The original XML file, in the 'from' format. Should not be null.

luceneDoc - A Lucene Document that holds content that may be used by the conversion class, or null.

Returns:

Content converted to the 'to' format, or null if unable to process.

canConvert

public boolean canConvert(String fromFormat,
                          String toFormat)

Determines whether this XMLConversionService can perform the given converstion. Returns true of the toFormat is the same as the fromFormat.

Parameters:

fromFormat - The format to convert from.

toFormat - The format to convert to.

Returns:

True if this XMLConversionService can perform the conversion.

getAvailableFormats

public ArrayList getAvailableFormats(String fromFormat)

Gets the metadata format conversions that are available for the given format, including the given format.

Parameters:

fromFormat - The format to convert from.

Returns:

The availableFormats.

addXslStylesheet

public void addXslStylesheet(String fromFormat,
                             String toFormat,
                             String xslFilePath)

Adds a XSL stylesheet that can convert from one XML format to another.

Parameters:

fromFormat - The XML format from which the stylesheet will convert.

toFormat - The XML format to which the stylesheet will convert.

xslFilePath - The absolute path to the stylesheet.

addJavaConverterClass

public void addJavaConverterClass(String fromFormat,
                                  String toFormat,
                                  String className,
                                  ServletContext servletContext)

Adds a concrete implementation of the XMLFormatConverter interface that can convert XML from one format to another. The class must be available in the classpath for Tomcat or the running JVM that is using this broker.

Parameters:

fromFormat - The XML format from which the class will convert.

toFormat - The XML format to which the class will convert.

className - The fully-qualified class that will perform the conversion.

servletContext - The feature to be added to the JavaConverterClass attribute

addXslConverterHelper

public boolean addXslConverterHelper(String paramVal,
                                     File xslFilesDirecoryPath)

Adds an XSL converter by parsing a String of the form [ fromFormat | toFormat | xslFileName ]. Useful for using initParameters to configure XML format converters.

Parameters:

paramVal - A String of the form [ fromFormat | toFormat | xslFileName ].

xslFilesDirecoryPath - The full path to the directory where the xsl file exists.

Returns:

False if the number of values parsed in paramVal is incorrect, otherwise true.

addJavaConverterHelper

public boolean addJavaConverterHelper(String paramVal,
                                      ServletContext servletContext)

Adds an Java class XML converter by parsing a String of the form [ fromFormat | toFormat | className ]. Useful for using initParameters to configure XML format converters.

Parameters:

paramVal - A String of the form [ fromFormat | toFormat | xslFileName ].

servletContext - The ServletContext that will be available to the class when it executes.

Returns:

False if the number of values parsed in paramVal is incorrect, otherwise true.

xmlConversionServiceFactoryForServlets

public static XMLConversionService xmlConversionServiceFactoryForServlets(ServletContext servletContext,
                                                                          File xslFilesDirecory,
                                                                          File xmlCachDirecory,
                                                                          boolean filterDeclarations)
                                                                   throws Exception

Factory for use in Servlets to create an XMLConversionService using configurations found in the Servlet context parameters. This method also places the path to the XSL files directory in the servlet context under 'xslFilesDirecoryPath', for use by the JavaXmlConverters.

To configure a format converter that uses an XSL style sheet or Java class, the context param-name must begin with the either 'xslconverter' or 'javaconverter' and must be unique. The param-value must be of the form 'xslfile.xsl|[from format]\[to format]' or '[fully qualified Java class]|[from format]\[to format]'.

Parameters:

servletContext - The ServletContext

xslFilesDirecory - The base directory where the XSL files are located

xmlCachDirecory - The directory where the service will cache the converted XML files

filterDeclarations - Set to true to filter out the XML and DTD declarations in the converted XML

Returns:

The XMLConversionService

Throws:

Exception - If error

stripXmlDeclaration

public static final StringBuffer stripXmlDeclaration(BufferedReader rdr)
                                              throws IOException

Strips the XML declaration and DTD declaration from the given XML. The resulting content is sutable for insertion inside an existing XML element.

Parameters:

rdr - A BufferedReader containing XML.

Returns:

Content with the XML and DTD declarations stipped out.

Throws:

IOException - If error

getContentFromXML

public static final String getContentFromXML(String input)

Gets the content from XML by stripping all XML tags. The input XML should be valid prior to calling this method.

Parameters:

input - A valid XML string.

Returns:

The contentFromXML.

getDateStamp

public static final String getDateStamp()

Gets a datestamp of the current time formatted for display with logs and output.

Returns:

A datestamp for display purposes.

setDebug

public static final void setDebug(boolean db)

Sets the debug attribute of the SimpleLuceneIndex object

Parameters:

db - The new debug value