How to handle collisions in guava table?

Question

Assume that we have a MyBean class with simple int count field, and Guava table like this;

Table<Integer, Integer, MyBean> table; // we can instantiate like HashBasedTable.create();

I want to sum count fields, when i put a new MyBean object and this position has an existing MyBean object in table.

table.put(1, 1, new MyBean(1)); 
table.put(1, 1, new MyBean(2)); // so what will be going on ?

Actually this is a very simple case and I want to work on complex objects if they are in collision.

Answer 1

The Table behaves just like a Map, i.e., the second put overwrites the first. What you'd need is sort of Multimap. There's an issue for a Multitable already, vote for it.

Currently, you can either use a

Table<Integer, Integer, SomeCollection<MyBean>>

or a

Map<SomePair<Integer, Integer>, MyBean>

I'd recommend the latter, as composing keys is way simpler than dealing with the "multi" stuff.

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If you're feeling really hacky today, you could even use

Map<Long, MyBean>

Just don't tell anybody it was me who proposed this. And encapsulate the hack properly, so you don't don't get bitten by some int to long automatic conversion somewhere.