// HandlerBase.java: Simple base class for AElfred processors.
// NO WARRANTY! See README, and copyright below.
// $Id: HandlerBase.java,v 1.1.1.1 2001/09/02 05:39:36 spestov Exp $
package com.microstar.xml;
import com.microstar.xml.XmlHandler;
import com.microstar.xml.XmlException;
import java.io.Reader;
/**
* Convenience base class for AElfred handlers.
* <p>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
* <code>charData</code> method, using the defaults for the others:
* <pre>
* 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));
* }
* }
* </pre>
* <p>This class is optional, but if you use it, you must also
* include the <code>XmlException</code> class.
* <p>Do not extend this if you are using SAX; extend
* <code>org.xml.sax.HandlerBase</code> instead.
* @author Copyright (c) 1998 by Microstar Software Ltd.
* @author written by David Megginson <dmeggins@microstar.com>
* @version 1.1
* @see XmlHandler
* @see XmlException
* @see org.xml.sax.HandlerBase
*/
public class HandlerBase implements XmlHandler {
/**
* Handle the start of the document.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>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.
* <p>The default implementation throws <code>XmlException</code>.
* @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);
}
}