/*
 * Copyright 1999-2004 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.
 */

/* $Id$ */

package org.apache.fop.fo.expr;

import org.apache.fop.datatypes.Numeric;
import org.apache.fop.fo.properties.Property;

/**
 * Class modelling the abs Number Function. See Sec. 5.10.1 of the XSL-FO spec.
 */
public class AbsFunction extends FunctionBase {

    /**
     * @return 1 (the number of arguments required for the abs function)
     */
    public int nbArgs() {
        return 1;
    }

    /**
     * @param args array of arguments to be evaluated, the first of which
     * should be a numeric value
     * @param propInfo the PropertyInfo object to be evaluated
     * @return the absolute value of the input
     * @throws PropertyException for non-numeric input
     */
    public Property eval(Property[] args,
                         PropertyInfo propInfo) throws PropertyException {
        Numeric num = args[0].getNumeric();
        if (num == null) {
            throw new PropertyException("Non numeric operand to abs function");
        }
        // TODO: What if it has relative components (percent, table-col units)?
        return (Property) NumericOp.abs(num);
    }

}