| // SAX entity resolver. |
| // http://www.saxproject.org |
| // No warranty; no copyright -- use this as you will. |
| // $Id: EntityResolver.java,v 1.10 2002/01/30 21:13:44 dbrownell 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> |
| * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> |
| * for further information. |
| * </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 |
| * @version 2.0.1 (sax2r2) |
| * @see org.xml.sax.XMLReader#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. 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).</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). 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. </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 |