1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 /* 19 * $Id: ExpressionContext.java 468637 2006-10-28 06:51:02Z minchau $ 20 */ 21 package org.apache.xalan.extensions; 22 23 import javax.xml.transform.ErrorListener; 24 25 import org.apache.xpath.objects.XObject; 26 import org.w3c.dom.Node; 27 import org.w3c.dom.traversal.NodeIterator; 28 29 /** 30 * An object that implements this interface can supply 31 * information about the current XPath expression context. 32 */ 33 public interface ExpressionContext 34 { 35 36 /** 37 * Get the current context node. 38 * @return The current context node. 39 */ getContextNode()40 public Node getContextNode(); 41 42 /** 43 * Get the current context node list. 44 * @return An iterator for the current context list, as 45 * defined in XSLT. 46 */ getContextNodes()47 public NodeIterator getContextNodes(); 48 49 /** 50 * Get the error listener. 51 * @return The registered error listener. 52 */ getErrorListener()53 public ErrorListener getErrorListener(); 54 55 /** 56 * Get the value of a node as a number. 57 * @param n Node to be converted to a number. May be null. 58 * @return value of n as a number. 59 */ toNumber(Node n)60 public double toNumber(Node n); 61 62 /** 63 * Get the value of a node as a string. 64 * @param n Node to be converted to a string. May be null. 65 * @return value of n as a string, or an empty string if n is null. 66 */ toString(Node n)67 public String toString(Node n); 68 69 /** 70 * Get a variable based on it's qualified name. 71 * 72 * @param qname The qualified name of the variable. 73 * 74 * @return The evaluated value of the variable. 75 * 76 * @throws javax.xml.transform.TransformerException 77 */ getVariableOrParam(org.apache.xml.utils.QName qname)78 public XObject getVariableOrParam(org.apache.xml.utils.QName qname) 79 throws javax.xml.transform.TransformerException; 80 81 /** 82 * Get the XPathContext that owns this ExpressionContext. 83 * 84 * Note: exslt:function requires the XPathContext to access 85 * the variable stack and TransformerImpl. 86 * 87 * @return The current XPathContext. 88 * @throws javax.xml.transform.TransformerException 89 */ getXPathContext()90 public org.apache.xpath.XPathContext getXPathContext() 91 throws javax.xml.transform.TransformerException; 92 93 } 94