| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 1999-2003 The Apache Software Foundation. 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 following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * 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 APACHE SOFTWARE FOUNDATION OR |
| * ITS 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 Apache Software Foundation and was |
| * originally based on software copyright (c) 1999, Lotus |
| * Development Corporation., http://www.lotus.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xpath.operations; |
| |
| import javax.xml.transform.TransformerException; |
| import org.apache.xml.dtm.DTM; |
| import org.apache.xml.dtm.DTMIterator; |
| import org.apache.xml.dtm.DTMManager; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.objects.XNodeSet; |
| import org.apache.xpath.objects.XObject; |
| |
| |
| /** |
| * This is a "smart" variable reference that is used in situations where |
| * an absolute path is optimized into a variable reference, but may |
| * be used in some situations where the document context may have changed. |
| * For instance, in select="document(doc/@href)//name[//salary > 7250]", the |
| * root in the predicate will be different for each node in the set. While |
| * this is easy to detect statically in this case, in other cases static |
| * detection would be very hard or impossible. So, this class does a dynamic check |
| * to make sure the document context of the referenced variable is the same as |
| * the current document context, and, if it is not, execute the referenced variable's |
| * expression with the current context instead. |
| */ |
| public class VariableSafeAbsRef extends Variable |
| { |
| |
| /** |
| * Dereference the variable, and return the reference value. Note that lazy |
| * evaluation will occur. If a variable within scope is not found, a warning |
| * will be sent to the error listener, and an empty nodeset will be returned. |
| * |
| * |
| * @param xctxt The runtime execution context. |
| * |
| * @return The evaluated variable, or an empty nodeset if not found. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public XObject execute(XPathContext xctxt, boolean destructiveOK) |
| throws javax.xml.transform.TransformerException |
| { |
| XNodeSet xns = (XNodeSet)super.execute(xctxt, destructiveOK); |
| DTMManager dtmMgr = xctxt.getDTMManager(); |
| int context = xctxt.getContextNode(); |
| if(dtmMgr.getDTM(xns.getRoot()).getDocument() != |
| dtmMgr.getDTM(context).getDocument()) |
| { |
| Expression expr = (Expression)xns.getContainedIter(); |
| xns = (XNodeSet)expr.asIterator(xctxt, context); |
| } |
| return xns; |
| } |
| |
| } |
| |