Application: gvSIG desktop » Library: org.gvsig.tools

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package org.gvsig.tools.math;

import java.math.BigDecimal;

import java.math.BigInteger;

import java.math.MathContext;

import org.apache.commons.lang3.mutable.MutableInt;

/**

 *

 * @author fdiaz

 */

public class BigDecimalUtils {

    public static BigDecimal force(BigDecimal d, int s, int p) {

        boolean hasExpectedScale = s>=0;

        if (d.precision() == p && (!hasExpectedScale || d.scale() == s)) {

            return d;

        }

        if (hasExpectedScale && d.scale() > s) {

            throw new ArithmeticException("Overflow: can't force value '"

                    + d.toString() + "' ("

                    + d.precision() + "." + d.scale() + ") to ("

                    + p + "," + s + ")");

        }

        if(hasExpectedScale){

            if (d.precision() - d.scale() > p - s) {

                throw new ArithmeticException("Overflow: can't force value '"

                        + d.toString() + "' ("

                        + d.precision() + "." + d.scale() + ") to ("

                        + p + "," + s + ")");

            }

            BigInteger unscaledValue = d.unscaledValue().multiply(BigInteger.TEN.pow(s-d.scale()));

            BigDecimal x = new BigDecimal(

                    unscaledValue, 

                    s, 

                    new MathContext(p));

            return x;

        } else {

            if (d.precision() > p) {

                throw new ArithmeticException("Overflow: can't force value '"

                        + d.toString() + "' ("

                        + d.precision() + "." + d.scale() + ") to ("

                        + p + "," + s + ")");

            }

            return d;

        }

    }

    public static boolean isValid(BigDecimal d, int s, int p) {

        if(d == null){

            return true;

        }

        if (d.precision() == p && d.scale() == s) {

            return true;

        }

        if (d.scale() > s) {

            return false;

        }

        if (d.precision() - d.scale() > p - s) {

            return false;

        }

        return true;

    }

    public static BigDecimal fixIfCan(BigDecimal d, MutableInt s, MutableInt p) {

        if (d.precision() == p.intValue() && d.scale() == s.intValue()) {

            return d;

        }

        if (d.scale() > s.intValue()) {

            p.setValue( d.precision() + (d.scale() - s.intValue()) );

            s.setValue(d.scale());

            return d;

        }

        if (d.precision() - d.scale() > p.intValue() - s.intValue()) {

            p.setValue(Math.max(d.precision(), p.intValue()));

            s.setValue(d.scale());

            return d;

        }

        BigInteger unscaledValue = d.unscaledValue().multiply(BigInteger.TEN.pow(s.intValue()-d.scale()));

        BigDecimal x = new BigDecimal(

                unscaledValue, 

                s.intValue(), 

                new MathContext(p.intValue()));

        return x;

    }

}