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Jaxen is a universal Java XPath engine.
/*
* $Header$
* $Revision$
* $Date$
*
* ====================================================================
*
* Copyright 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the Jaxen Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS 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 COPYRIGHT OWNER
* OR 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
* @deprecated will be removed in Jaxen 2.0
*/
public class PatternParser
{
private static final boolean TRACE = false;
private static final boolean USE_HANDLER = false;
public static Pattern parse(String text) throws JaxenException, org.jaxen.saxpath.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,
new PredicateSet()) );
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() )
{
FilterExpr filter = new DefaultFilterExpr(new PredicateSet());
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 ) )
{
return ! step.getPredicates().isEmpty();
}
else
{
return true;
}
}
}