In Groovy, you can use the ? operator, also known as the Elvis operator, to assign a value conditionally. The syntax is as follows:
def variable = someValue ?: defaultValue
This will assign someValue to variable if it is not null, otherwise it will assign defaultValue. Here are some examples:
def name = null
def greeting = "Hello, " + (name ?: "Anonymous")
println(greeting)
// Output: Hello, Anonymous
name = "Alice"
greeting = "Hello, " + (name ?: "Anonymous")
println(greeting)
// Output: Hello, Alice
In these examples, name is assigned a value of null at first, so the ? operator is used to check if name is null before concatenating it with the greeting. Since it is null, the default value "Anonymous" is used instead. Later, name is assigned a non-null value, so the ? operator uses that value instead.