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XML Pull parser library developed by Extreme Computing Lab, Indian University
/*
* $Header: /l/extreme/cvs/codes/xpp5/xis5/infoset_xpath_jaxen/org/xmlpull/infoset/xpath/jaxen/pattern/PatternParser.java,v 1.1 2005/05/16 23:59:26 aslom Exp $
* $Revision: 1.1 $
* $Date: 2005/05/16 23:59:26 $
*
* ====================================================================
*
* Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions, and the disclaimer that follows
* these conditions in the documentation and/or other materials
* provided with the distribution.
*
* 3. The name "Jaxen" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [email protected].
*
* 4. Products derived from this software may not be called "Jaxen", nor
* may "Jaxen" appear in their name, without prior written permission
* from the Jaxen Project Management ([email protected]).
*
* In addition, we request (but do not require) that you include in the
* end-user documentation provided with the redistribution and/or in the
* software itself an acknowledgement equivalent to the following:
* "This product includes software developed by the
* Jaxen Project (http://www.jaxen.org/)."
* Alternatively, the acknowledgment may be graphical using the logos
* available at http://www.jaxen.org/
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* ====================================================================
* This software consists of voluntary contributions made by many
* individuals on behalf of the Jaxen Project and was originally
* created by bob mcwhirter and
* James Strachan . For more information on the
* Jaxen Project, please see PatternParser is a helper class for parsing
* XSLT patterns
*
* @author James Strachan
*/
public class PatternParser
{
private static final boolean TRACE = false;
private static final boolean USE_HANDLER = false;
public static Pattern parse(String text) throws JaxenException, SAXPathException
{
if ( USE_HANDLER )
{
XPathReader reader = XPathReaderFactory.createReader();
PatternHandler handler = new PatternHandler();
handler.setXPathFactory( new DefaultXPathFactory() );
reader.setXPathHandler( handler );
reader.parse( text );
return handler.getPattern();
}
else
{
XPathReader reader = XPathReaderFactory.createReader();
JaxenHandler handler = new JaxenHandler();
handler.setXPathFactory( new DefaultXPathFactory() );
reader.setXPathHandler( handler );
reader.parse( text );
Pattern pattern = convertExpr( handler.getXPathExpr().getRootExpr() );
return pattern.simplify();
}
}
protected static Pattern convertExpr(Expr expr) throws JaxenException
{
if ( TRACE )
{
System.out.println( "Converting: " + expr + " into a pattern." );
}
if ( expr instanceof LocationPath )
{
return convertExpr( (LocationPath) expr );
}
else if ( expr instanceof FilterExpr )
{
LocationPathPattern answer = new LocationPathPattern();
answer.addFilter( (FilterExpr) expr );
return answer;
}
else if ( expr instanceof UnionExpr )
{
UnionExpr unionExpr = (UnionExpr) expr;
Pattern lhs = convertExpr( unionExpr.getLHS() );
Pattern rhs = convertExpr( unionExpr.getRHS() );
return new UnionPattern( lhs, rhs );
}
else
{
LocationPathPattern answer = new LocationPathPattern();
answer.addFilter( new DefaultFilterExpr( expr ) );
return answer;
}
}
protected static LocationPathPattern convertExpr(LocationPath locationPath) throws JaxenException
{
LocationPathPattern answer = new LocationPathPattern();
//answer.setAbsolute( locationPath.isAbsolute() );
List steps = locationPath.getSteps();
// go through steps backwards
LocationPathPattern path = answer;
boolean first = true;
for ( ListIterator iter = steps.listIterator( steps.size() ); iter.hasPrevious(); )
{
Step step = (Step) iter.previous();
if ( first )
{
first = false;
path = convertStep( path, step );
}
else
{
if ( navigationStep( step ) )
{
LocationPathPattern parent = new LocationPathPattern();
int axis = step.getAxis();
if ( axis == Axis.DESCENDANT || axis == Axis.DESCENDANT_OR_SELF )
{
path.setAncestorPattern( parent );
}
else
{
path.setParentPattern( parent );
}
path = parent;
}
path = convertStep( path, step );
}
}
if ( locationPath.isAbsolute() )
{
LocationPathPattern parent = new LocationPathPattern( NodeTypeTest.DOCUMENT_TEST );
path.setParentPattern( parent );
}
return answer;
}
protected static LocationPathPattern convertStep(LocationPathPattern path, Step step) throws JaxenException
{
if ( step instanceof DefaultAllNodeStep )
{
int axis = step.getAxis();
if ( axis == Axis.ATTRIBUTE )
{
path.setNodeTest( NodeTypeTest.ATTRIBUTE_TEST );
}
else
{
path.setNodeTest( NodeTypeTest.ELEMENT_TEST );
}
}
else if ( step instanceof DefaultCommentNodeStep )
{
path.setNodeTest( NodeTypeTest.COMMENT_TEST );
}
else if ( step instanceof DefaultProcessingInstructionNodeStep )
{
path.setNodeTest( NodeTypeTest.PROCESSING_INSTRUCTION_TEST );
}
else if ( step instanceof DefaultTextNodeStep )
{
path.setNodeTest( TextNodeTest.SINGLETON );
}
else if ( step instanceof DefaultCommentNodeStep )
{
path.setNodeTest( NodeTypeTest.COMMENT_TEST );
}
else if ( step instanceof DefaultNameStep )
{
DefaultNameStep nameStep = (DefaultNameStep) step;
String localName = nameStep.getLocalName();
String prefix = nameStep.getPrefix();
int axis = nameStep.getAxis();
short nodeType = Pattern.ELEMENT_NODE;
if ( axis == Axis.ATTRIBUTE )
{
nodeType = Pattern.ATTRIBUTE_NODE;
}
if ( nameStep.isMatchesAnyName() )
{
if ( prefix.length() == 0 || prefix.equals( "*" ) )
{
if ( axis == Axis.ATTRIBUTE )
{
path.setNodeTest( NodeTypeTest.ATTRIBUTE_TEST );
}
else
{
path.setNodeTest( NodeTypeTest.ELEMENT_TEST );
}
}
else
{
path.setNodeTest( new NamespaceTest( prefix, nodeType ) );
}
}
else
{
path.setNodeTest( new NameTest( localName, nodeType ) );
// XXXX: should support namespace in the test too
}
return convertDefaultStep(path, nameStep);
}
else if ( step instanceof DefaultStep )
{
return convertDefaultStep(path, (DefaultStep) step);
}
else
{
throw new JaxenException( "Cannot convert: " + step + " to a Pattern" );
}
return path;
}
protected static LocationPathPattern convertDefaultStep(LocationPathPattern path, DefaultStep step) throws JaxenException
{
List predicates = step.getPredicates();
if ( ! predicates.isEmpty() )
{
DefaultFilterExpr filter = new DefaultFilterExpr();
for ( Iterator iter = predicates.iterator(); iter.hasNext(); )
{
filter.addPredicate( (Predicate) iter.next() );
}
path.addFilter( filter );
}
return path;
}
protected static boolean navigationStep( Step step )
{
if ( step instanceof DefaultNameStep )
{
return true;
}
else
if ( step.getClass().equals( DefaultStep.class ) )
{
DefaultStep defaultStep = (DefaultStep) step;
return ! step.getPredicates().isEmpty();
}
else
{
return true;
}
}
}