[when]Something is {colour}=Something(colour=="{colour}")

KieServices kieServices = KieServices.Factory.get();
KieFileSystem kfs = kieServices.newKieFileSystem();
int count = 0;
for (String rule : ruleBodies) {
    count++;
    kfs.write("src/main/resources/Rule" + count + ".dslr",
        kieServices.getResources().newReaderResource(new StringReader(rule)));
}
String dsl = "[when]Something is {colour}=Something(colour=="{colour}")";
kfs.write("src/main/resources/DSL.dsl",
    kieServices.getResources().newReaderResource(new StringReader(dsl)));
KieBuilder kieBuilder = kieServices.newKieBuilder(kfs).buildAll()

[when]{enity:.*}={entity}