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A collection of software for aggregatting and processing environmental data such as from NOAA GOES satellites.
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/*
* $Id$
*
* $Source$
*
* $State$
*
* $Log$
* Revision 1.1 2008/04/04 18:21:10 cvs
* Added legacy code to repository
*
* Revision 1.9 2004/08/30 14:50:40 mjmaloney
* Javadocs
*
* Revision 1.8 2004/01/29 16:27:56 mjmaloney
* XmlHierarchyParser can now set file-name by a delegation Locator.
*
* Revision 1.7 2004/01/27 15:28:48 mjmaloney
* dev
*
* Revision 1.6 2002/07/07 14:24:29 chris
* Cosmetic changes only: I added considerable javadoc comments describing
* this class.
*
* Revision 1.5 2001/04/23 17:33:19 mike
* dev
*
* Revision 1.4 2001/04/11 22:44:20 mike
* Added StringBufferErrorHandler.
*
* Revision 1.3 2001/01/08 15:38:45 mike
* dev
*
* Revision 1.2 2000/12/29 02:50:07 mike
* dev
*
* Revision 1.1 2000/12/21 21:30:11 mike
* Created
*
*
*/
package ilex.xml;
import org.xml.sax.*;
import java.util.Stack;
import java.util.EmptyStackException;
import ilex.xml.XmlObjectParser;
/**
* XmlHierarchyParser parses an XML document by using a hierarchy of object
* parsers.
*
* Each layer of the object hierarchy is handled by an XmlObjectParser,
* whose job it is to map XML tags to internal variables and lower-level
* objects.
*
*
* Typically, parsing an XML file will be handled by one of these objects,
* which contains a Stack of XmlObjectParsers. At any instant, this stack
* corresponds to the particular point in the XML element hierarchy.that
* parsing is currently being done. The SAX event methods are delegated
* by this object to the top-most XmlObjectParser on the stack,
* corresponding to the deepest-level element currently being parsed.
*
*
* This object never handles any SAX event methods itself. If the
* stack is empty, that's considered an error.
*
*
* See the
* ilex.test.XmlParserTester
* program for more information.
*
*/
public class XmlHierarchyParser implements ContentHandler
{
private Locator locator;
private Stack objectParsers;
private ErrorHandler errorHandler;
private String filename;
/**
* Constructor. The caller must ensure that errorHandler is not null.
* @param errorHandler the error handler
*/
public XmlHierarchyParser( ErrorHandler errorHandler )
{
objectParsers = new Stack();
this.errorHandler = errorHandler;
this.filename = "";
}
/**
* Set the error handler. The argument eh must not be null.
* @param eh the error handler
*/
public void setErrorHandler( ErrorHandler eh )
{
this.errorHandler = eh;
}
/**
* Pushes a new element parser onto the stack.
* @param parser the new parser
*/
public void pushObjectParser( XmlObjectParser parser )
{
objectParsers.push(parser);
}
/**
* Pops the top parser off the stack.
* @return the popped parser.
* @throws SAXException if stack is empty
*/
public XmlObjectParser popObjectParser( ) throws SAXException
{
try
{
XmlObjectParser p = (XmlObjectParser)objectParsers.pop();
return p;
}
catch(EmptyStackException ex)
{
throw new SAXException("Attempt to pop an empty parser stack");
}
}
//==================================================================
// Methods that override the SAX ContentHandler interface:
//==================================================================
/**
* @param locator
*/
public void setDocumentLocator( Locator locator )
{
this.locator = new MyLocator(locator, filename);
}
/**
* @throws SAXException
*/
public void startDocument( ) throws SAXException
{
}
/**
* @throws SAXException
*/
public void endDocument( ) throws SAXException
{
}
/**
* @param prefix
* @param uri
* @throws SAXException
*/
public void startPrefixMapping( String prefix, String uri ) throws SAXException
{
}
/**
* @param prefix
* @throws SAXException
*/
public void endPrefixMapping( String prefix ) throws SAXException
{
}
/**
* Called when SAX sees an element start tag.
* Delegate to the top parser on the stack.
* @param namespaceURI passed to top parser
* @param localName passed to top parser
* @param qName passed to top parser
* @param atts passed to top parser
* @throws SAXException if thrown from top parser
*/
public void startElement( String namespaceURI, String localName, String qName, Attributes atts ) throws SAXException
{
try
{
// Delegate this to the Object Parser on the top of the stack.
XmlObjectParser parser = (XmlObjectParser)objectParsers.peek();
parser.startElement(this, namespaceURI, localName, qName, atts);
}
catch(EmptyStackException ex)
{
throw new SAXException(
"Elements found after top level element ended.");
}
catch(SAXException ex)
{
// Add location information to application exceptions.
errorHandler.error(new SAXParseException(ex.getMessage(), locator));
}
}
/**
* Called when SAX sees an end tag.
* Delegate this info to the top parser on the stack.
* @param namespaceURI passed to top parser
* @param localName passed to top parser
* @param qName passed to top parser
* @throws SAXException
*/
public void endElement( String namespaceURI, String localName, String qName ) throws SAXException
{
try
{
// Delegate this to the Object Parser on the top of the stack.
XmlObjectParser parser = (XmlObjectParser)objectParsers.peek();
parser.endElement(this, namespaceURI, localName, qName);
}
catch(EmptyStackException ex)
{
throw new SAXException(
"End-Element found after top level element ended.");
}
catch(SAXException ex)
{
// Add location information to application exceptions.
errorHandler.error(new SAXParseException(ex.getMessage(), locator));
}
}
/**
* Delegate this info to the top parser on the stack.
* @param ch the characters
* @param start the start
* @param length the length.
* @throws SAXException if thrown from top parser
*/
public void characters( char[] ch, int start, int length ) throws SAXException
{
try
{
// Delegate this to the Object Parser on the top of the stack.
XmlObjectParser parser = (XmlObjectParser)objectParsers.peek();
parser.characters(ch, start, length);
}
catch(EmptyStackException ex)
{
throw new SAXException(
"Characters found after top level element ended.");
}
catch(SAXException ex)
{
// Add location information to application exceptions.
errorHandler.error(new SAXParseException(ex.getMessage(), locator));
}
}
/**
* Delegate this info to the top parser on the stack.
* @param ch the whitespace characters
* @param start the start
* @param length the length.
* @throws SAXException if thrown from top parser
*/
public void ignorableWhitespace( char[] ch, int start, int length ) throws SAXException
{
try
{
// Delegate this to the Object Parser on the top of the stack.
XmlObjectParser parser = (XmlObjectParser)objectParsers.peek();
parser.ignorableWhitespace(ch, start, length);
}
catch(EmptyStackException ex)
{
throw new SAXException(
"Whitespace found after top level element ended.");
}
catch(SAXException ex)
{
// Add location information to application exceptions.
errorHandler.error(new SAXParseException(ex.getMessage(), locator));
}
}
/**
* Does nothing.
* @param target ignored
* @param data ignored
*/
public void processingInstruction( String target, String data ) throws SAXException
{
}
/**
* Does nothing.
* @param name ignored.
*/
public void skippedEntity( String name ) throws SAXException
{
}
/**
* Sets the file name
* @param fn the file name
*/
public void setFileName( String fn )
{
this.filename = fn;
}
class MyLocator implements Locator
{
private Locator loc;
String filename;
/**
* @param loc
* @param fn
*/
public MyLocator( Locator loc, String fn )
{
this.loc = loc;
this.filename = fn;
}
/**
* @return
*/
public int getColumnNumber( )
{
return loc.getColumnNumber();
}
/**
* @return
*/
public int getLineNumber( )
{
return loc.getLineNumber();
}
/**
* @return
*/
public String getPublicId( )
{
return filename;
}
/**
* @return
*/
public String getSystemId( )
{
return loc.getSystemId();
}
}
}