Commons JXPath example source code file (KeywordVariables.java)

This example Commons JXPath source code file (KeywordVariables.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

cannot, cannot, illegalargumentexception, keywordvariables, keywordvariables, object, object, string, unsupportedoperationexception, unsupportedoperationexception, variables

The Commons JXPath KeywordVariables.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.servlet;

import org.apache.commons.jxpath.Variables;

/**
 * Implementation of the Variables interface that provides access
 * to a single object using a reserved name (keyword).
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 652925 $ $Date: 2008-05-02 17:05:41 -0500 (Fri, 02 May 2008) $
 */
public class KeywordVariables implements Variables {
    private static final long serialVersionUID = 894145608741325442L;

    private String keyword;
    private Object object;

    /**
     * Create a new KeywordVariables.
     * @param keyword String
     * @param object value
     */
    public KeywordVariables(String keyword, Object object) {
        if (keyword == null) {
            throw new IllegalArgumentException("keyword cannot be null");
        }
        this.keyword = keyword;
        this.object = object;
    }

    public boolean isDeclaredVariable(String variable) {
        return variable.equals(keyword);
    }

    public Object getVariable(String variable) {
        return isDeclaredVariable(variable) ? object : null;
    }

    public void declareVariable(String variable, Object value) {
        throw new UnsupportedOperationException(
            "Cannot declare new keyword variables.");
    }

    public void undeclareVariable(String variable) {
        throw new UnsupportedOperationException(
            "Cannot undeclare keyword variables.");
    }
}