CODEWITHSUNDEEP
javaandroidjava-8java-stream
Roi Amiel
Roi Amiel

Reputation: 365

Java streams, create custom stateful operation

I want to create my own stateful operation with streams, for example, I want to create a custom reduce operation, that combine some of the items and some not (according to my rules), for example: [1, 2, 3, 4] -> [1 + 2, 3 + 4].

It will be nice if I could implement my version of java.util.stream.DistinctOps but since I can't, I need another way to implement my operations.

Meanwhile, in order to implement this operation, I collected the stream, performed my operation and then returned a new stream:

public Stream<Integer> myOperation(Stream<Integer> stream) {
    List<Integer> list = stream.collect(toList());
    list = preform operation...
    return list.stream();
}

But I want to implement this operation without performing a terminal operation, Any ideas?.

Thanks.

Upvotes: 2

Views: 247

Answers (1)

Louis Wasserman
Louis Wasserman

Reputation: 198211

But I want to implement this operation without performing a terminal operation, Any ideas?.

There is really, truly, no way to do it without performing a terminal operation. All intermediate, nonterminal operations on streams are "rigid" in the sense that they don't permit you to perform custom behavior like this.

Upvotes: 2

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