//Define value or assign it dynamically for target and source as shown below
def tValue = 0
def sValue = 1
def json = new groovy.json.JsonBuilder()
json {
source sValue
target tValue
}
println json.toPrettyString()
Ly9EZWZpbmUgdmFsdWUgb3IgYXNzaWduIGl0IGR5bmFtaWNhbGx5IGZvciB0YXJnZXQgYW5kIHNvdXJjZSBhcyBzaG93biBiZWxvdwpkZWYgdFZhbHVlID0gMApkZWYgc1ZhbHVlID0gMQoKZGVmIGpzb24gPSBuZXcgZ3Jvb3Z5Lmpzb24uSnNvbkJ1aWxkZXIoKQpqc29uIHsKICBzb3VyY2Ugc1ZhbHVlCiAgdGFyZ2V0IHRWYWx1ZQp9CnByaW50bG4ganNvbi50b1ByZXR0eVN0cmluZygp