286N/A * reserved comment block 286N/A * DO NOT REMOVE OR ALTER! 286N/A * Copyright 1999-2004 The Apache Software Foundation. 286N/A * Licensed under the Apache License, Version 2.0 (the "License"); 286N/A * you may not use this file except in compliance with the License. 286N/A * You may obtain a copy of the License at 286N/A * Unless required by applicable law or agreed to in writing, software 286N/A * distributed under the License is distributed on an "AS IS" BASIS, 286N/A * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 286N/A * See the License for the specific language governing permissions and 286N/A * limitations under the License. 286N/A * This is a "smart" variable reference that is used in situations where 286N/A * an absolute path is optimized into a variable reference, but may 286N/A * be used in some situations where the document context may have changed. 286N/A * For instance, in select="document(doc/@href)//name[//salary > 7250]", the 286N/A * root in the predicate will be different for each node in the set. While 286N/A * this is easy to detect statically in this case, in other cases static 286N/A * detection would be very hard or impossible. So, this class does a dynamic check 286N/A * to make sure the document context of the referenced variable is the same as 286N/A * the current document context, and, if it is not, execute the referenced variable's 286N/A * expression with the current context instead. 286N/A * Dereference the variable, and return the reference value. Note that lazy 286N/A * evaluation will occur. If a variable within scope is not found, a warning 286N/A * will be sent to the error listener, and an empty nodeset will be returned. 286N/A * @param xctxt The runtime execution context. 286N/A * @return The evaluated variable, or an empty nodeset if not found. 286N/A * @throws javax.xml.transform.TransformerException