Amountの単項マイナス演算子のテスト(要JScience)

TestAmountNegative.groovy

import org.jscience.physics.amount.*

def a = Amount.valueOf("1 m")
def b = Amount.valueOf("2 m")

Amount.metaClass.negative {
    opposite()
}

def c = a + -b

assert c == Amount.valueOf("-1 m")

JScience - http://jscience.org/
http://www.java2s.com/Code/Jar/JKL/Downloadjsciencejar.htm