uk.me.nxg.xoxa
Class SigningXMLReader

java.lang.Object
  org.xml.sax.helpers.XMLFilterImpl
      uk.me.nxg.xoxa.SigningXMLReader

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler, XMLFilter, XMLReader

public class SigningXMLReader
extends org.xml.sax.helpers.XMLFilterImpl

An XML reader which can sign and verify XML in passing. This is an implementation of the SAX XMLReader interface, and may be used as such.

Normally, you obtain a SAX reader using a SAXParserFactory; if you instead obtain a reader using the getXMLReader(File,String,String) method, then it can be used in the same way as any other parser, except that:

• If there is a <?signature ...?> processing instruction in the input XML, which has an attribute algorithm="http://ns.nxg.me.uk/xoxa/algo#openpgp", then the signature will be checked, and another <?signature ...?> PI generated, with information about the verification.
• If there is no such PI, then the input XML will be signed, and a new PI generated.
• If the PI is present, but the algorithm attribute is missing or has a different value from the above, then the class throws a XoxaException.

In each of the first two cases, further information can be retrieved about the parse using the information object returned by getGPGInformation(org.xml.sax.XMLReader).

Field Summary

static String

OPENPGP

Method Summary

void	characters(char[] ch, int start, int length)
void	endDocument()
void	endElement(String uri, String localName, String qName)
void	endPrefixMapping(String prefix)
GPGInformation	getGPGInformation() Retrieves extra information about the work done by the XMLReader.
static GPGInformation	getGPGInformation(XMLReader r) Retrieves extra information about the work done by the SigningXMLReader which is passed as argument.
static XMLReader	getXMLReader() Obtains a new XMLreader which can verify input XML.
static XMLReader	getXMLReader(File gpgHome, String identity, String passphrase) Obtains a new XMLReader which can either sign or verify input XML.
static XMLFilter	getXMLReader(File gpgHome, String identity, String passphrase, XMLReader xmlReader) Wraps an existing reader in a SigningXMLReader.
void	ignorableWhitespace(char[] ch, int start, int length)
void	parse(InputSource is)
void	processingInstruction(String target, String data)
void	setDocumentLocator(Locator locator)
void	skippedEntity(String name)
void	startDocument()
void	startElement(String uri, String localName, String qName, Attributes atts)
void	startPrefixMapping(String prefix, String uri)

Methods inherited from class org.xml.sax.helpers.XMLFilterImpl

error, fatalError, getContentHandler, getDTDHandler, getEntityResolver, getErrorHandler, getFeature, getParent, getProperty, notationDecl, parse, resolveEntity, setContentHandler, setDTDHandler, setEntityResolver, setErrorHandler, setFeature, setParent, setProperty, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

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

Field Detail

OPENPGP

public static final String OPENPGP

See Also:

Constant Field Values

Method Detail

getGPGInformation

public static GPGInformation getGPGInformation(XMLReader r)

Retrieves extra information about the work done by the SigningXMLReader which is passed as argument. If no GPG work has been done so far by the reader, or if the reader is not a SigningXMLReader, then returns null.

Parameters:

r - an XMLReader, typically a SigningXMLReader

Returns:

status information about the GPG work, or null if the argument is not a SigningXMLReader

getGPGInformation

public GPGInformation getGPGInformation()

Retrieves extra information about the work done by the XMLReader. If no GPG work has been done so far by the reader, then returns null.

Returns:

status information about the GPG work

getXMLReader

public static XMLReader getXMLReader()
                              throws SAXException

Obtains a new XMLreader which can verify input XML. This uses GPG information in the default location, or that pointed to by GNUPGHOME. Equivalent to getXMLReader(null, null, null)

Returns:

a new XMLReader instance

Throws:

SAXException - on XML errors

getXMLReader

public static XMLReader getXMLReader(File gpgHome,
                                     String identity,
                                     String passphrase)
                              throws SAXException

Obtains a new XMLReader which can either sign or verify input XML. If either the identity or the passphrase is null, then the reader can only verify signatures, and if no signature is present then it will not attempt to add one

The gpgHome parameter indicates the location of the GPG keys to be used -- it is equivalent to, and overrides, the environment variable GNUPGHOME. It may be null to use the default location.

Parameters:

gpgHome - the location of the GPG keys to be used, or null

identity - the GPG identity to use to sign keys, or null

passphrase - the passphrase for the key associated with the identity, or null

Returns:

a new XMLReader instance

Throws:

SAXException - if SAX does

getXMLReader

public static XMLFilter getXMLReader(File gpgHome,
                                     String identity,
                                     String passphrase,
                                     XMLReader xmlReader)
                              throws SAXException

Wraps an existing reader in a SigningXMLReader.

Parameters:

gpgHome - the location of the GPG keys to be used, or null

identity - the GPG identity to use to sign keys, or null

passphrase - the passphrase for the key associated with the identity, or null

xmlReader - a XMLReader instance

Returns:

a new XMLFilter

Throws:

SAXException - if SAX does

characters

public void characters(char[] ch,
                       int start,
                       int length)
                throws SAXException

Specified by:

characters in interface ContentHandler

Overrides:

characters in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)
                         throws SAXException

Specified by:

ignorableWhitespace in interface ContentHandler

Overrides:

ignorableWhitespace in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

processingInstruction

public void processingInstruction(String target,
                                  String data)
                           throws SAXException

Specified by:

processingInstruction in interface ContentHandler

Overrides:

processingInstruction in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

setDocumentLocator

public void setDocumentLocator(Locator locator)

Specified by:

setDocumentLocator in interface ContentHandler

Overrides:

setDocumentLocator in class org.xml.sax.helpers.XMLFilterImpl

skippedEntity

public void skippedEntity(String name)
                   throws SAXException

Specified by:

skippedEntity in interface ContentHandler

Overrides:

skippedEntity in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

startDocument

public void startDocument()
                   throws SAXException

Specified by:

startDocument in interface ContentHandler

Overrides:

startDocument in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

endDocument

public void endDocument()
                 throws SAXException

Specified by:

endDocument in interface ContentHandler

Overrides:

endDocument in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

startElement

public void startElement(String uri,
                         String localName,
                         String qName,
                         Attributes atts)
                  throws SAXException

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

endElement

public void endElement(String uri,
                       String localName,
                       String qName)
                throws SAXException

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

startPrefixMapping

public void startPrefixMapping(String prefix,
                               String uri)
                        throws SAXException

Specified by:

startPrefixMapping in interface ContentHandler

Overrides:

startPrefixMapping in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

endPrefixMapping

public void endPrefixMapping(String prefix)
                      throws SAXException

Specified by:

endPrefixMapping in interface ContentHandler

Overrides:

endPrefixMapping in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

parse

public void parse(InputSource is)
           throws SAXException,
                  IOException

Specified by:

parse in interface XMLReader

Overrides:

parse in class org.xml.sax.helpers.XMLFilterImpl

Throws:

SAXException

IOException