Package com.microstar.xml

Class HandlerBase

java.lang.Object

com.microstar.xml.HandlerBase

All Implemented Interfaces:

XmlHandler

Direct Known Subclasses:

DocManager, MoMLParser, MultipageParser, PlotBoxMLParser, PtalonMLHandler

public class HandlerBase
extends java.lang.Object
implements XmlHandler

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.

Since:

Ptolemy II 0.2

Version:

1.1

Author:

Copyright (c) 1998 by Microstar Software Ltd., written by David Megginson <dmeggins@microstar.com>

See Also:

XmlHandler, XmlException

Constructor Summary

Constructors

Constructor	Description
HandlerBase()

Method Summary

Modifier and Type	Method	Description
void	attribute(java.lang.String aname, java.lang.String value, boolean isSpecified)	Handle an attribute assignment.
void	charData(char[] ch, int start, int length)	Handle character data.
void	doctypeDecl(java.lang.String name, java.lang.String publicId, java.lang.String systemId)	Handle a document type declaration.
void	endDocument()	Handle the end of the document.
void	endElement(java.lang.String elname)	Handle the end of an element.
void	endExternalEntity(java.lang.String systemId)	Handle the end of an external entity.
void	error(java.lang.String message, java.lang.String systemId, int line, int column)	Throw an exception for a fatal error.
void	ignorableWhitespace(char[] ch, int start, int length)	Handle ignorable whitespace.
void	processingInstruction(java.lang.String target, java.lang.String data)	Handle a processing instruction.
java.lang.Object	resolveEntity(java.lang.String publicId, java.lang.String systemId)	Resolve an external entity.
void	startDocument()	Handle the start of the document.
void	startElement(java.lang.String elname)	Handle the start of an element.
void	startExternalEntity(java.lang.String systemId)	Handle the start of an external entity.

Methods inherited from class java.lang.Object

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

Constructor Detail

HandlerBase

public HandlerBase()

Method Detail

startDocument

public void startDocument()
                   throws java.lang.Exception

Handle the start of the document.

The default implementation does nothing.

Specified by:

startDocument in interface XmlHandler

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.startDocument()

endDocument

public void endDocument()
                 throws java.lang.Exception

Handle the end of the document.

The default implementation does nothing.

Specified by:

endDocument in interface XmlHandler

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.endDocument()

resolveEntity

public java.lang.Object resolveEntity(java.lang.String publicId,
                                      java.lang.String systemId)
                               throws java.lang.Exception

Resolve an external entity.

The default implementation simply returns the supplied system identifier.

Specified by:

resolveEntity in interface XmlHandler

Parameters:

publicId - The public identifier, or null if none was supplied.

systemId - The system identifier.

Returns:

The replacement system identifier, or null to use the default.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.resolveEntity(java.lang.String, java.lang.String)

startExternalEntity

public void startExternalEntity(java.lang.String systemId)
                         throws java.lang.Exception

Handle the start of an external entity.

The default implementation does nothing.

Specified by:

startExternalEntity in interface XmlHandler

Parameters:

systemId - The URI of the external entity that is starting.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.startExternalEntity(java.lang.String)

endExternalEntity

public void endExternalEntity(java.lang.String systemId)
                       throws java.lang.Exception

Handle the end of an external entity.

The default implementation does nothing.

Specified by:

endExternalEntity in interface XmlHandler

Parameters:

systemId - The URI of the external entity that is ending.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.endExternalEntity(java.lang.String)

doctypeDecl

public void doctypeDecl(java.lang.String name,
                        java.lang.String publicId,
                        java.lang.String systemId)
                 throws java.lang.Exception

Handle a document type declaration.

The default implementation does nothing.

Specified by:

doctypeDecl in interface XmlHandler

Parameters:

name - The document type name.

publicId - The public identifier, or null if unspecified.

systemId - The system identifier, or null if unspecified.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.doctypeDecl(java.lang.String, java.lang.String, java.lang.String)

attribute

public void attribute(java.lang.String aname,
                      java.lang.String value,
                      boolean isSpecified)
               throws java.lang.Exception

Handle an attribute assignment.

The default implementation does nothing.

Specified by:

attribute in interface XmlHandler

Parameters:

aname - The name of the attribute.

value - The value of the attribute, or null if the attribute is #IMPLIED.

isSpecified - True if the value was specified, false if it was defaulted from the DTD.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.attribute(java.lang.String, java.lang.String, boolean)

startElement

public void startElement(java.lang.String elname)
                  throws java.lang.Exception

Handle the start of an element.

The default implementation does nothing.

Specified by:

startElement in interface XmlHandler

Parameters:

elname - The element type name.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.startElement(java.lang.String)

endElement

public void endElement(java.lang.String elname)
                throws java.lang.Exception

Handle the end of an element.

The default implementation does nothing.

Specified by:

endElement in interface XmlHandler

Parameters:

elname - The element type name.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.endElement(java.lang.String)

charData

public void charData(char[] ch,
                     int start,
                     int length)
              throws java.lang.Exception

Handle character data.

The default implementation does nothing.

Specified by:

charData in interface XmlHandler

Parameters:

ch - The character data.

start - The starting position in the array.

length - The number of characters available.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.charData(char[], int, int)

ignorableWhitespace

public void ignorableWhitespace(char[] ch,
                                int start,
                                int length)
                         throws java.lang.Exception

Handle ignorable whitespace.

The default implementation does nothing.

Specified by:

ignorableWhitespace in interface XmlHandler

Parameters:

ch - The literal whitespace characters.

start - The starting position in the array.

length - The number of whitespace characters available.

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.ignorableWhitespace(char[], int, int)

processingInstruction

public void processingInstruction(java.lang.String target,
                                  java.lang.String data)
                           throws java.lang.Exception

Handle a processing instruction.

The default implementation does nothing.

Specified by:

processingInstruction in interface XmlHandler

Parameters:

target - The target (the name at the start of the PI).

data - The data, if any (the rest of the PI).

Throws:

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.processingInstruction(java.lang.String, java.lang.String)

error

public void error(java.lang.String message,
                  java.lang.String systemId,
                  int line,
                  int column)
           throws XmlException,
                  java.lang.Exception

Throw an exception for a fatal error.

The default implementation throws XmlException.

Specified by:

error in interface XmlHandler

Parameters:

message - The error message.

systemId - The system identifier of the entity that contains the error.

line - The approximate line number of the error.

column - The approximate column number of the error.

Throws:

XmlException - A specific parsing error.

java.lang.Exception - Derived methods may throw exceptions.

See Also:

XmlHandler.error(java.lang.String, java.lang.String, int, int)