01: package org.codehaus.groovy.runtime.typehandling;
02:
03: import java.math.BigDecimal;
04:
05: /**
06: * BigDecimal NumberMath operations
07: *
08: * @author Steve Goetze
09: */
10: public class BigDecimalMath extends NumberMath {
11:
12: //This is an arbitrary value, picked as a reasonable choice for a rounding point
13: //for typical user math.
14: public static final int MAX_DIVISION_SCALE = 10;
15:
16: protected static BigDecimalMath instance = new BigDecimalMath();
17:
18: private BigDecimalMath() {
19: }
20:
21: protected Number absImpl(Number number) {
22: return toBigDecimal(number).abs();
23: }
24:
25: protected Number addImpl(Number left, Number right) {
26: return toBigDecimal(left).add(toBigDecimal(right));
27: }
28:
29: protected Number subtractImpl(Number left, Number right) {
30: return toBigDecimal(left).subtract(toBigDecimal(right));
31: }
32:
33: protected Number multiplyImpl(Number left, Number right) {
34: return toBigDecimal(left).multiply(toBigDecimal(right));
35: }
36:
37: protected Number divideImpl(Number left, Number right) {
38: //Hack until Java 1.5 BigDecimal is available. For now, pick
39: //a result scale which is the maximum of the scale of the
40: //two operands and an arbitrary maximum (similar to what a
41: //handheld calculator would do). Then, normalize the result
42: //by removing any trailing zeros.
43: BigDecimal bigLeft = toBigDecimal(left);
44: BigDecimal bigRight = toBigDecimal(right);
45: int scale = Math.max(bigLeft.scale(), bigRight.scale());
46: return normalize(bigLeft.divide(bigRight, Math.max(scale,
47: MAX_DIVISION_SCALE), BigDecimal.ROUND_HALF_UP));
48: }
49:
50: protected int compareToImpl(Number left, Number right) {
51: return toBigDecimal(left).compareTo(toBigDecimal(right));
52: }
53:
54: private BigDecimal normalize(BigDecimal number) {
55: // we have to take care of the case number==0, because 0 can have every
56: // scale and the test in the while loop would never end
57: if (number.signum() == 0) {
58: // the smallest scale for 0 is 0
59: return number.setScale(0);
60: }
61: // rescale until we found the smallest possible scale
62: try {
63: while (true) {
64: number = number.setScale(number.scale() - 1);
65: }
66: } catch (ArithmeticException e) {
67: return number;
68: }
69: }
70:
71: protected Number negateImpl(Number left) {
72: return toBigDecimal(left).negate();
73: }
74: }
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