Primitive streams and optional (original) (raw)

Doug Lea dl at cs.oswego.edu
Wed Nov 28 07:27:11 PST 2012

On 11/26/12 15:43, Brian Goetz wrote:

1. Ban nulls. This is equivalent to adding .tee(e -> { if (e == null) throw new NPE(); } between all stages of a pipeline.

2. Ignore nulls. This is what Doug is proposing, and is equivalent to adding .filter(e -> e != null) between all stages of a pipeline. 3. Tolerate nulls. This treat nulls as "just another value" and hopes that lambdas and downstream stages can deal.

In case anyone was thinking that these have anything to do with efficiency, remember that JVMs are required to null-check each non-explicity-checked use of any reference anyway. So these three choices have similar costs.

(They do vary a little: #3 will sometimes be the most expensive, since the lack of a pre-null-check forces twistier code paths to be generated later on first dereference of a field.)

-Doug

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