/*
* Copyright 1998-2009 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
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* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
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* software or in any product that includes this software. The names UCAR
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*
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package thredds.catalog2.xml.parser.stax;
import thredds.catalog2.builder.ThreddsBuilder;
import thredds.catalog2.builder.ThreddsBuilderFactory;
import thredds.catalog2.xml.parser.ThreddsXmlParserException;
import thredds.catalog2.xml.parser.ThreddsXmlParserIssue;
import javax.xml.stream.events.XMLEvent;
import javax.xml.stream.events.StartElement;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLEventReader;
import javax.xml.namespace.QName;
/**
* _more_
*
* @author edavis
* @since 4.0
*/
abstract class AbstractElementParser
{
org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger( getClass() );
final QName elementName;
final XMLEventReader reader;
final ThreddsBuilderFactory builderFactory;
AbstractElementParser( QName elementName, XMLEventReader reader,
ThreddsBuilderFactory builderFactory )
{
if ( elementName == null || reader == null || builderFactory == null )
throw new IllegalArgumentException( "Element name, XMLEventReader, and/or BuilderFactory may not be null.");
this.elementName = elementName;
this.reader = reader;
this.builderFactory = builderFactory;
}
boolean isSelfElement( XMLEvent event ) {
return StaxThreddsXmlParserUtils.isEventStartOrEndElementWithMatchingName( event, this.elementName );
}
abstract void parseStartElement()
throws ThreddsXmlParserException;
abstract void handleChildStartElement()
throws ThreddsXmlParserException;
abstract void postProcessingAfterEndElement()
throws ThreddsXmlParserException;
abstract ThreddsBuilder getSelfBuilder();
final ThreddsBuilder parse()
throws ThreddsXmlParserException
{
try
{
this.parseStartElement();
while ( this.reader.hasNext() )
{
XMLEvent event = this.reader.peek();
if ( event.isStartElement() )
{
this.handleChildStartElement();
}
else if ( event.isEndElement() )
{
if ( this.isSelfElement( event.asEndElement() ) )
{
this.reader.next();
break;
}
else
{
if ( this instanceof ThreddsMetadataElementParser )
{
if ( log.isDebugEnabled())
{
String msg = "End element probably parent of ThreddsMetadata [" + event.asEndElement().getName() + "].";
ThreddsXmlParserIssue issue = StaxThreddsXmlParserUtils
.createIssueForUnexpectedEvent( msg, ThreddsXmlParserIssue.Severity.WARNING,
this.reader, event );
// ToDo Figure out a better way to deal with this situation.
log.debug( "parse(): " + issue.getMessage() );
}
break;
}
else
{
String msg = "Unrecognized end element [" + event.asEndElement().getName() + "].";
ThreddsXmlParserIssue issue = StaxThreddsXmlParserUtils
.createIssueForUnexpectedEvent( msg, ThreddsXmlParserIssue.Severity.FATAL,
this.reader, event );
log.error( this.getClass().getName() + ".parse(): " + issue.getMessage() );
// ToDo Gather issues (and "this.reader.next(); continue;") rather than throw exception.
throw new ThreddsXmlParserException( issue );
}
}
}
else
{
log.debug( this.getClass().getName() + ".parse(): Unhandled event [" + event.getLocation() + "--" + event + "]." );
this.reader.next();
continue;
}
}
this.postProcessingAfterEndElement();
return this.getSelfBuilder();
}
catch ( XMLStreamException e )
{
log.error( "parse(): Failed to parse " + this.elementName + " element: " + e.getMessage(), e );
throw new ThreddsXmlParserException( "Failed to parse " + this.elementName + " element: " + e.getMessage(), e );
}
}
StartElement getNextEventIfStartElementIsMine()
throws ThreddsXmlParserException
{
if ( ! this.reader.hasNext() )
throw new ThreddsXmlParserException( "XMLEventReader has no further events." );
StartElement startElement = null;
try
{
XMLEvent event = this.reader.peek();
if ( ! event.isStartElement() )
throw new ThreddsXmlParserException( "Next event must be StartElement." );
if ( ! event.asStartElement().getName().equals( this.elementName ) )
throw new ThreddsXmlParserException( "Start element must be an '" + this.elementName.getLocalPart() + "' element." );
startElement = this.reader.nextEvent().asStartElement();
}
catch ( XMLStreamException e )
{
throw new ThreddsXmlParserException( "Problem reading from XMLEventReader." );
}
return startElement;
}
StartElement peekAtNextEventIfStartElement()
throws ThreddsXmlParserException
{
if ( ! this.reader.hasNext() )
throw new ThreddsXmlParserException( "XMLEventReader has no further events." );
StartElement startElement = null;
while ( this.reader.hasNext() )
{
XMLEvent event = null;
try
{
event = this.reader.peek();
}
catch (XMLStreamException e)
{
String msg = "Problem reading from XMLEventReader.";
ThreddsXmlParserIssue issue = StaxThreddsXmlParserUtils
.createIssueForException( msg, this.reader, e);
log.error("peekAtNextEventIfStartElement(): " + issue.getMessage());
// ToDo Gather issues rather than throw exception.
throw new ThreddsXmlParserException(issue);
}
if (event.isStartElement())
{
startElement = event.asStartElement();
break;
}
else if( event.isCharacters() && event.asCharacters().isWhiteSpace())
{
// Skip any whitespace characters.
this.reader.next();
}
else
{
String msg = "Expecting StartElement for next event [" + event.getClass().getName() + "]";
ThreddsXmlParserIssue issue = StaxThreddsXmlParserUtils
.createIssueForUnexpectedEvent( msg, ThreddsXmlParserIssue.Severity.FATAL, this.reader,event );
log.error( "peekAtNextEventIfStartElement(): " + issue.getMessage());
// ToDo Gather issues rather than throw exception.
throw new ThreddsXmlParserException( issue );
}
}
return startElement;
}
}