// HandlerBase.java: Simple base class for AElfred processors. // NO WARRANTY! See README, and copyright below. // $Id: HandlerBase.java 38798 2005-07-08 20:00:01Z cxh $ package com.microstar.xml; /** * Convenience base class for AElfred handlers. *
This base class implements the XmlHandler interface with
* (mostly empty) default handlers. You are not required to use this,
* but if you need to handle only a few events, you might find
* it convenient to extend this class rather than implementing
* the entire interface. This example overrides only the
* charData
method, using the defaults for the others:
*
* import com.microstar.xml.HandlerBase; * * public class MyHandler extends HandlerBase { * public void charData (char ch[], int start, int length) * { * System.out.println("Data: " + new String (ch, start, length)); * } * } **
This class is optional, but if you use it, you must also
* include the XmlException
class.
*
Do not extend this if you are using SAX; extend
* org.xml.sax.HandlerBase
instead.
* @author Copyright (c) 1998 by Microstar Software Ltd.
* @author written by David Megginson <dmeggins@microstar.com>
* @version 1.1
* @since Ptolemy II 0.2
* @see XmlHandler
* @see XmlException
*/
public class HandlerBase implements XmlHandler {
/**
* Handle the start of the document.
*
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#startDocument * @exception java.lang.Exception Derived methods may throw exceptions. */ public void startDocument() throws java.lang.Exception { } /** * Handle the end of the document. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#endDocument * @exception java.lang.Exception Derived methods may throw exceptions. */ public void endDocument() throws java.lang.Exception { } /** * Resolve an external entity. *
The default implementation simply returns the supplied * system identifier. * @see com.microstar.xml.XmlHandler#resolveEntity * @exception java.lang.Exception Derived methods may throw exceptions. */ public Object resolveEntity(String publicId, String systemId) throws java.lang.Exception { return null; } /** * Handle the start of an external entity. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#startExternalEntity * @exception java.lang.Exception Derived methods may throw exceptions. */ public void startExternalEntity(String systemId) throws java.lang.Exception { } /** * Handle the end of an external entity. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#endExternalEntity * @exception java.lang.Exception Derived methods may throw exceptions. */ public void endExternalEntity(String systemId) throws java.lang.Exception { } /** * Handle a document type declaration. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#doctypeDecl * @exception java.lang.Exception Derived methods may throw exceptions. */ public void doctypeDecl(String name, String publicId, String systemId) throws java.lang.Exception { } /** * Handle an attribute assignment. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#attribute * @exception java.lang.Exception Derived methods may throw exceptions. */ public void attribute(String aname, String value, boolean isSpecified) throws java.lang.Exception { } /** * Handle the start of an element. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#startElement * @exception java.lang.Exception Derived methods may throw exceptions. */ public void startElement(String elname) throws java.lang.Exception { } /** * Handle the end of an element. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#endElement * @exception java.lang.Exception Derived methods may throw exceptions. */ public void endElement(String elname) throws java.lang.Exception { } /** * Handle character data. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#charData * @exception java.lang.Exception Derived methods may throw exceptions. */ public void charData(char[] ch, int start, int length) throws java.lang.Exception { } /** * Handle ignorable whitespace. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#ignorableWhitespace * @exception java.lang.Exception Derived methods may throw exceptions. */ public void ignorableWhitespace(char[] ch, int start, int length) throws java.lang.Exception { } /** * Handle a processing instruction. *
The default implementation does nothing. * @see com.microstar.xml.XmlHandler#processingInstruction * @exception java.lang.Exception Derived methods may throw exceptions. */ public void processingInstruction(String target, String data) throws java.lang.Exception { } /** * Throw an exception for a fatal error. *
The default implementation throws XmlException
.
* @see com.microstar.xml.XmlHandler#error
* @exception com.microstar.xml.XmlException A specific parsing error.
* @exception java.lang.Exception Derived methods may throw exceptions.
*/
public void error(String message, String systemId, int line, int column)
throws XmlException, java.lang.Exception {
throw new XmlException(message, systemId, line, column);
}
}