/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.jxpath;
import java.util.List;
/**
* If an extenstion function has an argument of type ExpressionContext,
* it can gain access to the current node of an XPath expression context.
* <p>
* Example:
* <blockquote><pre>
* public class MyExtenstionFunctions {
* public static String objectType(ExpressionContext context){
* Object value = context.getContextNodePointer().getValue();
* if (value == null){
* return "null";
* }
* return value.getClass().getName();
* }
* }
* </pre></blockquote>
*
* You can then register this extension function using a {@link ClassFunctions
* ClassFunctions} object and call it like this:
* <blockquote><pre>
* "/descendent-or-self::node()[ns:objectType() = 'java.util.Date']"
* </pre></blockquote>
* This expression will find all nodes of the graph that are dates.
*/
public interface ExpressionContext {
/**
* Get the JXPathContext in which this function is being evaluated.
*
* @return A list representing the current context nodes.
*/
JXPathContext getJXPathContext();
/**
* Get the current context node.
*
* @return The current context node pointer.
*/
Pointer getContextNodePointer();
/**
* Get the current context node list. Each element of the list is
* a Pointer.
*
* @return A list representing the current context nodes.
*/
List getContextNodeList();
/**
* Returns the current context position.
* @return int
*/
int getPosition();
}
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