CODEWITHSUNDEEP
javareflection
JUG
JUG

Reputation: 703

Execute nested method calls from Method object

I need to make a call to following method -

testObj.getA().getB().getC().getD();

Above, testObj.getA() returns object A which has a method getB(), which returns object B that has method getC(), which returns object C and it has method getD().

How can I invoke it using reflection? If I try Method object as following -

Method m = testObj.getClass().getMethod("getA().getB().getC().getD(), null));

Above fails saying the method is not found. Any suggestions?

Upvotes: 1

Views: 1850

Answers (2)

user4910279
user4910279

Reputation:

You can use Apache Commons BeanUtils. 

D d = (D)PropertyUtils.getNestedProperty(testObj, "a.b.c.d");

See here.

Upvotes: 2

Stack Exchange Broke The Law
Stack Exchange Broke The Law

Reputation: 58909

You don't have a method called getA().getB().getC().getD(), so it's no surprise you can't get it. You have four separate methods.

There's nothing stopping you from calling them all through reflection, but you have to treat it as four separate method calls (because it is):

TypeOfA a = testObj.getClass().getMethod("getA").invoke(testObj);
TypeOfB b = TypeOfA.class.getMethod("getB").invoke(a);
TypeOfC c = TypeOfB.class.getMethod("getC").invoke(b);
TypeOfD d = TypeOfC.class.getMethod("getD").invoke(c);

Upvotes: 4

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