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Commons JXPath example source code file (ExpressionContext.java)

This example Commons JXPath source code file (ExpressionContext.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons JXPath tags/keywords

expressioncontext, expressioncontext, jxpathcontext, jxpathcontext, list, list, pointer, pointer, util

The Commons JXPath ExpressionContext.java source code

/*
 * 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>
 * public class MyExtenstionFunctions {
 *    public static String objectType(ExpressionContext context){
 *       Object value = context.getContextNodePointer().getValue();
 *       if (value == null){
 *           return "null";
 *       }
 *       return value.getClass().getName();
 *    }
 * }
 * </pre>
 *
 * You can then register this extension function using a {@link ClassFunctions
 * ClassFunctions} object and call it like this:
 * <blockquote>
 *   "/descendent-or-self::node()[ns:objectType() = 'java.util.Date']"
 * </pre>
 * 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();
}

Other Commons JXPath examples (source code examples)

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