How come I cannot declare an array of People in Groovy as shown.
Maybe I'm lacking the deeper understanding of classes
class People {
Integer id
}
class Job {
def func() {
People[] p = new People[10]
}
}
I get an error of People[] cannot be applied to app.People[]
The code sample you have shown does not reproduce the error you mentioned in the question above. It's broken actually and does not compile - method func() is missing its body. If you correct the code to e.g.
class People {
Integer id
}
class Job {
def func() {
People[] p = new People[10]
assert p.size() == 10
println p
}
}
new Job().func()
you will see it produces the expected result - check it out in the Groovy web console here. When you run it you will see following output to the console:
[null, null, null, null, null, null, null, null, null, null]
When it comes to array initialization there is one significant difference between Groovy and Java. In Java you can initialize an array of People[] like this:
People[] p = new People[] { new People(), new People(), /* ... */ new People() };
It wont work in Groovy, because Groovy reserves {} for closures. In Groovy you can initialize such array as:
People[] p = [new People(), new People(), new People()] as People[]
While Szymon Stepniak's answer is correct for Groovy 2.5 and below, Java-style array initialization are part of the enhancements of Groovy 3.0 and 2.6 made possible by the new parrot parser.
Example from the release notes:
def primes = new int[] {2, 3, 5, 7, 11}
assert primes.size() == 5 && primes.sum() == 28
assert primes.class.name == '[I'
def pets = new String[] {'cat', 'dog'}
assert pets.size() == 2 && pets.sum() == 'catdog'
assert pets.class.name == '[Ljava.lang.String;'
// traditional Groovy alternative still supported
String[] groovyBooks = [ 'Groovy in Action', 'Making Java Groovy' ]
assert groovyBooks.every{ it.contains('Groovy') }
Szymon Stepniak's answer is correct. I'll point another example of a real case in some unit test that I've worked (general Object type):
Object[] o = [YourModel] as Object[]
This is sufficient to mock a general Object with your model properties.
