Dynamic object graph navigation in Groovy - groovy

Question

folks!
I want to be able to navigate Groovy object graph dynamically, having the path in string:
def person = new Person("john", new Address("main", new Zipcode("10001", "1234")))
def path = 'address.zip.basic'
I know that I can access a property in map notation, but it's only one level deep:
def path = 'address'
assert person[path] == address
Is there any way to evaluate deeper path?
Thanks!

Answer 1

This can be achieved by overriding the getAt operator and traversing the property graph. The following code uses Groovy Category but inheritance or mixins could also be used.
class ZipCode {
String basic
String segment
ZipCode(basic, segment) {
this.basic = basic
this.segment = segment
}
}
class Address {
String name
ZipCode zip
Address(String name, ZipCode zip) {
this.name = name
this.zip = zip
}
}
class Person {
String name
Address address
Person(String name, Address address) {
this.name = name
this.address = address
}
}
#Category(Object)
class PropertyPath {
static String SEPARATOR = '.'
def getAt(String path) {
if (!path.contains(SEPARATOR)) {
return this."${path}"
}
def firstPropName = path[0..path.indexOf(SEPARATOR) - 1]
def remainingPath = path[path.indexOf(SEPARATOR) + 1 .. -1]
def firstProperty = this."${firstPropName}"
firstProperty[remainingPath]
}
}
def person = new Person('john', new Address('main', new ZipCode('10001', '1234')))
use(PropertyPath) {
assert person['name'] == 'john'
assert person['address.name'] == 'main'
assert person['address.zip.basic'] == '10001'
}
PropertyPath.SEPARATOR = '/'
use(PropertyPath) {
assert person['address/zip/basic'] == '10001'
}