// SAX entity resolver. | |
// No warranty; no copyright -- use this as you will. | |
// $Id: EntityResolver.java,v 1.1 2000/10/02 02:43:17 sboag Exp $ | |
package org.xml.sax; | |
import java.io.IOException; | |
/** | |
* Basic interface for resolving entities. | |
* | |
* <blockquote> | |
* <em>This module, both source code and documentation, is in the | |
* Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> | |
* </blockquote> | |
* | |
* <p>If a SAX application needs to implement customized handling | |
* for external entities, it must implement this interface and | |
* register an instance with the SAX driver using the | |
* {@link org.xml.sax.XMLReader#setEntityResolver setEntityResolver} | |
* method.</p> | |
* | |
* <p>The XML reader will then allow the application to intercept any | |
* external entities (including the external DTD subset and external | |
* parameter entities, if any) before including them.</p> | |
* | |
* <p>Many SAX applications will not need to implement this interface, | |
* but it will be especially useful for applications that build | |
* XML documents from databases or other specialised input sources, | |
* or for applications that use URI types other than URLs.</p> | |
* | |
* <p>The following resolver would provide the application | |
* with a special character stream for the entity with the system | |
* identifier "http://www.myhost.com/today":</p> | |
* | |
* <pre> | |
* import org.xml.sax.EntityResolver; | |
* import org.xml.sax.InputSource; | |
* | |
* public class MyResolver implements EntityResolver { | |
* public InputSource resolveEntity (String publicId, String systemId) | |
* { | |
* if (systemId.equals("http://www.myhost.com/today")) { | |
* // return a special input source | |
* MyReader reader = new MyReader(); | |
* return new InputSource(reader); | |
* } else { | |
* // use the default behaviour | |
* return null; | |
* } | |
* } | |
* } | |
* </pre> | |
* | |
* <p>The application can also use this interface to redirect system | |
* identifiers to local URIs or to look up replacements in a catalog | |
* (possibly by using the public identifier).</p> | |
* | |
* @since SAX 1.0 | |
* @author David Megginson, | |
* <a href="mailto:sax@megginson.com">sax@megginson.com</a> | |
* @version 2.0 | |
* @see org.xml.sax.Parser#setEntityResolver | |
* @see org.xml.sax.InputSource | |
*/ | |
public interface EntityResolver { | |
/** | |
* Allow the application to resolve external entities. | |
* | |
* <p>The Parser will call this method before opening any external | |
* entity except the top-level document entity (including the | |
* external DTD subset, external entities referenced within the | |
* DTD, and external entities referenced within the document | |
* element): the application may request that the parser resolve | |
* the entity itself, that it use an alternative URI, or that it | |
* use an entirely different input source.</p> | |
* | |
* <p>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).</p> | |
* | |
* <p>If the system identifier is a URL, the SAX parser must | |
* resolve it fully before reporting it to the application.</p> | |
* | |
* @param publicId The public identifier of the external entity | |
* being referenced, or null if none was supplied. | |
* @param systemId The system identifier of the external entity | |
* being referenced. | |
* @return An InputSource object describing the new input source, | |
* or null to request that the parser open a regular | |
* URI connection to the system identifier. | |
* @exception org.xml.sax.SAXException Any SAX exception, possibly | |
* wrapping another exception. | |
* @exception java.io.IOException A Java-specific IO exception, | |
* possibly the result of creating a new InputStream | |
* or Reader for the InputSource. | |
* @see org.xml.sax.InputSource | |
*/ | |
public abstract InputSource resolveEntity (String publicId, | |
String systemId) | |
throws SAXException, IOException; | |
} | |
// end of EntityResolver.java |