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Questions - functional-interface

Why casting is required with compose method but not with andThen Method

I have following expression that gets executed successfully: Function<Long,Long> y = ((Function<Long,Long>)(x -> x*x)).andThen(x -> x+1).andThen(x -> x+2); I understand why casti...
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Tarun

java

lambda

java-8

functional-interface

Votes: 0

Answers: 2

Latest Answer

Why do we need casting with compose calls but not with andThen calls? The two methods are different. compose() takes a function whose input is of a type that is not necessarily the same as the curre...
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ernest_k

Why and When should I use Functional Interfaces

Say I am writing a Consumer which prints something on the console. Then why shouldn't I directly use the System.out.println() method instead of creating a Consumer? Similarly, say I want to return a r...
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Ashish Singh

java

lambda

method-reference

functional-interface

Votes: 0

Answers: 2

Latest Answer

Functional interfaces should of course only be used where it is reasonable, and not everywhere. It is closely related to abstraction and generalization. Good examples for this can be seen in the Java ...
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Marcono1234

What would a compose method in the BiFunction interface look like?

The Function interface has the compose() and andThen() methods while the BiFunction interface only has the andThen() method. My question is simply how could the corresponding method be implemented? I'...
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PianoMastR64

java

function

functional-interface

function-composition

Votes: 0

Answers: 1

Latest Answer

The Function's Compose() and andThen() methods are straightforward since a Function has one input and one output and therefore can only be strung sequentially with another in two ways. Since a BiFunct...
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PianoMastR64

Correct way to apply different fucntions based on condition in stream

What would be the correct way to implement this functional logic with streams? Stream through list of items Check if condition 1 passes, if so apply function 1 to the item. Check if condition 2 pass...
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ems19

java

java-8

java-stream

functional-interface

supplier

Votes: 0

Answers: 1

Latest Answer

You're probably best off with a simple for loop, but you could do: List<Item> list; list.stream() .forEach(item -> { boolean condition1 = predicate1.test(item); boolean cond...
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Thomas Timbul

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