net.sf.saxon.lib

Class StandardEntityResolver

java.lang.Object

net.sf.saxon.lib.StandardEntityResolver

All Implemented Interfaces:

EntityResolver

public class StandardEntityResolver
extends Object
implements EntityResolver

This class is an EntityResolver used to resolve references to common DTDs and entity files, using local copies provided with the Saxon product. It has become necessary to do this because W3C is no longer serving these files from its server. Ideally the job of caching these files would belong to the XML parser, but because many of the parsers were issued years ago, they cannot be relied on to do it.

Field Summary

Fields

Modifier and Type	Field and Description
Configuration	config

Constructor Summary

Constructors

Constructor and Description
StandardEntityResolver()

Method Summary

Methods

Modifier and Type	Method and Description
static InputSource	fetch(String filename, Configuration config) Get the source from a given file.
static StandardEntityResolver	getInstance() Get a general-purpose instance of this class.
protected InputSource	getResource(String resourceName, Configuration config) Get a resource from the classpath.
static void	register(String publicId, String systemId, String fileName) Register a DTD or other entity to be resolved by this entity resolver
InputSource	resolveEntity(String publicId, String systemId) Allow the application to resolve external entities.
void	setConfiguration(Configuration config) Set configuration details.

Methods inherited from class java.lang.Object

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

Field Detail

config

public Configuration config

Constructor Detail

StandardEntityResolver

public StandardEntityResolver()

Method Detail

getInstance

public static StandardEntityResolver getInstance()

Get a general-purpose instance of this class. This should be treated as immutable, since it is shared with other users. That is, it should not be associated with any configuration.

Returns:

the singleton, general-purpose instance of this class

register

public static void register(String publicId,
            String systemId,
            String fileName)

Register a DTD or other entity to be resolved by this entity resolver

Parameters:

publicId - the public identifier of the DTD or entity

systemId - the system identifier of the DTD or entity

fileName - the fileName of the Saxon local copy of the resource, relative to the data directory in the JAR file

setConfiguration

public void setConfiguration(Configuration config)

Set configuration details. This is used to control tracing of accesses to files

Parameters:

config - the Saxon configuration

resolveEntity

public InputSource resolveEntity(String publicId,
                        String systemId)
                          throws SAXException,
                                 IOException

Allow the application to resolve external entities.

The parser will call this method before opening any external entity except the top-level document entity. Such entities include the external DTD subset and external parameter entities referenced within the DTD (in either case, only if the parser reads external parameter entities), and external general entities referenced within the document element (if the parser reads external general entities). The application may request that the parser locate the entity itself, that it use an alternative URI, or that it use data provided by the application (as a character or byte input stream).

Application writers can use this method to redirect external system identifiers to secure and/or local URIs, to look up public identifiers in a catalogue, or to read an entity from a database or other input source (including, for example, a dialog box). Neither XML nor SAX specifies a preferred policy for using public or system IDs to resolve resources. However, SAX specifies how to interpret any InputSource returned by this method, and that if none is returned, then the system ID will be dereferenced as a URL.

If the system identifier is a URL, the SAX parser must resolve it fully before reporting it to the application.

Specified by:

resolveEntity in interface EntityResolver

Parameters:

publicId - The public identifier of the external entity being referenced, or null if none was supplied.

systemId - The system identifier of the external entity being referenced.

Returns:

An InputSource object describing the new input source, or null to request that the parser open a regular URI connection to the system identifier.

Throws:

SAXException - Any SAX exception, possibly wrapping another exception.

IOException - A Java-specific IO exception, possibly the result of creating a new InputStream or Reader for the InputSource.

See Also:

InputSource

fetch

public static InputSource fetch(String filename,
                Configuration config)

Get the source from a given file.

Parameters:

filename - the name of the file

config - the Saxon Configuration

Returns:

an InputSource representing the contents of the file.

getResource

protected InputSource getResource(String resourceName,
                      Configuration config)

Get a resource from the classpath. This method is called if the URI uses the (Spring-defined) "classpath" URI scheme. It attempts to locate the resource on the classpath and returns an InputSource containing the relevant InputStream. If the inputstream cannot be located, it returns null. A subclass that does not want classpath URIs to be resolved in this way should override this method to return null unconditionally.

Parameters:

resourceName - the resource to be fetched from the classpath

config - the Saxon Configuration object

Returns:

an InputSource representing the named resource (fetched from the classpath) or null if no resource is available.