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Operators
Philip Ford edited this page Sep 16, 2018
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Groovy uses the same operators as in Java, but adds some others.
A more concise ternary operator which says, "if the expression is null, do this."
def sampleText
// Normal ternary operator.
def ternaryOutput = (sampleText != null) ? sampleText : 'Hello Groovy!'
// The Elvis operator in action. We must read: 'If sampleText is not null assign
// sampleText to elvisOuput, otherwise assign 'Viva Las Vegas!' to elvisOutput.
def elvisOutput = sampleText ?: 'Viva Las Vegas!'TBD
TBD
TBD
TBD
TBD
While Groovy can use the same operators as Java, operators are all implemented by methods in Groovy. This means we can do operator overriding in our own classes. This is very useful and can make more concise code.
| Operator | Method |
|---|---|
| a + b | a.plus(b) |
| a - b | a.minus(b) |
| a * b | a.multiply(b) |
| a ** b | a.power(b) |
| a / b | a.div(b) |
| a % b | a.mod(b) |
| a | b | a.or(b) |
| a & b | a.and(b) |
| a ^ b | a.xor(b) |
| a++ or ++a | a.next() |
| a-- or --a | a.previous() |
| a[b] | a.getAt(b) |
| a[b] = c | a.putAt(b, c) |
| a << b | a.leftShift(b) |
| a >> b | a.rightShift(b) |
| a >>> b | a.rightShiftUnsigned(b) |
| switch(a) { case(b) : } | b.isCase(a) |
| ~a | a.negate() |
| -a | a.negative() |
| +a | a.positive() |
| a == b | a.equals(b) |
| a != b | ! a.equals(b) |
| a <⇒ b | a.compareTo(b) |
| a > b | a.compareTo(b) > 0 |
| a >= b | a.compareTo(b) >= 0 |
| a < b | a.compareTo(b) < 0 |
| a ⇐ b | a.compareTo(b) ⇐ 0 |
class Money {
def amount
Money plus(Money other) {
new Money(amount: this.amount + other.amount)
}
boolean equals(Object other) {
amount == other.amount
}
int hashCode() {
amount.hashCode()
}
String toString() {
amount
}
}
def m1 = new Money(amount: 100)
def m2 = new Money(amount: 1)
assert (m1 + m2).amount == 101 // plus()
assert m1 + m2 == new Money(amount: 101) // equals() and plus()