Null safe Collection as Stream in Java 8

Question

I am looking for method that can make stream of collection, but is null safe. If collection is null, empty stream is returned. Like this:

Utils.nullSafeStrea         


        

Answer 1

Your collectionAsStream() method can be simplified to a version even simpler than when using Optional:

public static  Stream collectionAsStream(Collection collection) {
    return collection == null ? Stream.empty() : collection.stream();
}

Note that in most cases, it's probably better to just test for nullness before building the stream pipeline:

if (collection != null) {
    collection.stream().filter(...)
} // else do nothing

What you want seems to be only useful when you need to return the stream (including for flatmapping), or maybe concatenate it with another one.