Is there a Groovy equivalent to Gradle findProperty? - groovy

Question

I'm looking for a way to avoid having to check for the property first with hasProperty().
Ideally I would like to have something like
def a = myobj.getPropertyOrElse("mypropname", "defaultvalueifpropertymissing')
I see that gradle has a findProperty() but I can't find a similar thing for plain groovy.

Answer 1

The hasProperty method returns a MetaProperty instance that you can use to retrieve the value by passing the original instance:
def a = myobj.hasProperty('mypropname')?.getProperty(myobj) ?:
'defaultvalueifpropertymissing'
And then use the Safe navigation operator(?.) and Elvis operator (?:) to avoid the if/else.

Answer 2

The shortest version I could think of is
def a = if (a.hasProperty("mypropname")) a.getProperty("mypropname") else "defaultvalueifmissing"
which obviously repeats the property name twice. Creating your own method is possible but it's limited to your current class.
class MyClass {
String name = "the name"
}
def a = new MyClass()
def getProperty(Object theInstance, String propName, Object defaultValue) {
if (theInstance.hasProperty(propName)) theInstance.getProperty(propName) else defaultValue
}
assert "the name" == getProperty(a, "name", "")
assert "default value" == getProperty(a, "method", "default value")

Answer 3

One can use getProperties() of MetaClass or getProperty() of GroovyObject:
class Test {
String field1
String field2
}
def test = new Test(field1: "value1", field2: null)
// using MetaClass.getProperties()
println test.properties["field1"] // value1
println test.properties["field2"] // null
println "field2" in test.properties.keySet() // true
println test.properties["field3"] // null
println "field3" in test.properties.keySet() // false
// using GroovyObject.getProperty()
println test.getProperty("field1") // value1
println test.getProperty("field2") // null
println test.getProperty("field3") // groovy.lang.MissingPropertyException