Traverse tree with results. Maybe type in Java?

Posted by Angelo.Hannes on Programmers See other posts from Programmers or by Angelo.Hannes
Published on 2014-06-10T16:59:43Z Indexed on 2014/06/10 21:46 UTC
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I need to check a tree's node state. It can either be OK or NOT_OK. But that state is dependent on its children. So for a node to be OK, every of its children needs to be OK. If one or more of its children is NOT_OK the whole node is NOT_OK. To determine the state of a node I need to aggregate some properties of the node.

So I thought of two possible implementations. And they are more or less covered in this question: Why is Option/Maybe considered a good idea and checked exceptions are not?

Exception

I could pass the properties up the recursion path, and throw an exception if something went wrong.

Maybe

I implement an Maybe type and let it either hold an error or the aggregated properties. Maybe it is more an Either.

I tend towards the last option. And I'm thinking of an enum with two objects. Where I can additionally set those aggregated properties.

Am I on the right track?

I'm not familiar with the new JDK8 functional stuff. But I'm stuck on JDK7 anyway, so please focus on JDK7.

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