Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.numeric;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class AbsFunction extends AbstractFunction {

    public AbsFunction() {

        super("Numeric", "ABS",Range.is(1),

            "Returns the absolute value of a double value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned. Special cases:\n" +

            "- If the argument is positive zero or negative zero, the result is positive zero.\n" +

            "- If the argument is infinite, the result is positive infinity.\n" +

            "- If the argument is NaN, the result is NaN.\n" +

            "In other words, the result is the same as the value of the expression:\n" +

            "Double.longBitsToDouble((Double.doubleToLongBits(a)<<1)>>>1)",

            "ABS({{a}})",

            new String[]{

                "a - the argument whose absolute value is to be determined"

            },

            "Double",

            true

        );

    }

    @Override

    public boolean allowConstantFolding() {

        return true;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) {

        Object op1 = args[0];

        if( op1 instanceof Double ) {

            double value = Math.abs(((Number) op1).doubleValue());

            return value;

        }

        if( op1 instanceof Float ) {

            float value = Math.abs(((Number) op1).floatValue());

            return value;

        }

        if( op1 instanceof Long ) {

            long value = Math.abs(((Number) op1).longValue());

            return value;

        }

        if( op1 instanceof Integer ) {

            int value = Math.abs(((Number) op1).intValue());

            return value;

        }

        throw new IllegalArgumentException("Types not allowed in '"+name()+"' function.");

    }

}