UnaryOperExpression.java

/*
* JBoss, Home of Professional Open Source
* Copyright 2008-10 Red Hat and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
* @authors Andrew Dinn
*/
package org.jboss.byteman.rule.expression;

import org.jboss.byteman.rule.exception.TypeException;
import org.jboss.byteman.rule.type.Type;
import org.jboss.byteman.rule.Rule;
import org.jboss.byteman.rule.grammar.ParseNode;

/**
 * unary operators includes boolean NOT and arithmetic TWIDDLE
 * n.b. unary MINUS is not currently supported except as part of number
 * parsing
 */
public abstract class UnaryOperExpression extends OperExpression
{
    public UnaryOperExpression(Rule rule, int oper, Type type, ParseNode token, Expression operand)
    {
        super(rule, oper, type, token);
        this.operand = operand;
    }

    /**
     * verify that variables mentioned in this expression are actually available in the supplied
     * bindings list and infer/validate the type of this expression or its subexpressions
     * where possible
     *
     * @throws TypeException if any variable is missing or has the wrong type
     */
    public void bind() throws TypeException {
        // we just need to ensure that the operand can find its bindings
        operand.bind();
    }

    /**
     * return the operand with the given index or null if the index is out of range
     * @param index the operand index
     * @return the operand with the given index
     */
    public Expression getOperand(int index)
    {
        if (index != 0) {
            return null;
        }

        return operand;
    }

    private Expression operand;
}