ASTNotNode.java :  » Library » Apache-commons-jexl-1.1 » org » apache » commons » jexl » parser » Java Open Source

/*
 * Copyright 2002-2006 The Apache Software Foundation.
 *
 * Licensed 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.jexl.parser;

import org.apache.commons.jexl.JexlContext;
import org.apache.commons.jexl.util.Coercion;

/**
 * Not : 'not' or '!'.
 * 
 * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
 * @version $Id: ASTNotNode.java 398270 2006-04-30 03:02:58Z dion $
 */

public class ASTNotNode extends SimpleNode {
    /**
     * Create the node given an id.
     * 
     * @param id node id.
     */
    public ASTNotNode(int id) {
        super(id);
    }

    /**
     * Create a node with the given parser and id.
     * 
     * @param p a parser.
     * @param id node id.
     */
    public ASTNotNode(Parser p, int id) {
        super(p, id);
    }

    /** {@inheritDoc} */
    public Object jjtAccept(ParserVisitor visitor, Object data) {
        return visitor.visit(this, data);
    }

    /** {@inheritDoc} */
    public Object value(JexlContext jc) throws Exception {
        Object val = ((SimpleNode) jjtGetChild(0)).value(jc);

        /*
         * coercion rules
         */

        Boolean b = Coercion.coerceBoolean(val);

        if (b != null) {
            return b.booleanValue() ? Boolean.FALSE : Boolean.TRUE;
        }

        throw new Exception("expression not boolean valued");
    }

}