Does Java 8 provide a good way to repeat a value or function?

Strategy Guide to Repetition in Java 8

Java 8 encompasses an array of tactics for recurring an event or function, giving you more flexibility in crafting your desired code flow.

IntStream.range: The Unloved Integer Collection

Here's the deal with IntStream.range. It creates a sequence of integers and uses each one to trigger an action. It's like the shy guy always standing in the corner at a party - incredibly useful but often overlooked:

IntStream.range(0, 5).forEach(i -> System.out.println("Number: " + i));
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What does IntStream.map do? Let's dig deeper

We can use IntStream.map to transform a sequence's values based on a function. It's like magic - but with math.

IntStream.range(1, 4).map(n -> n * n).forEach(System.out::println); // Now you're playing with power
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Collections.nCopies With Streams: When You Want More, But Not Too Much

When you need to repeat a value without creating an entire collection, Collections.nCopies and streams can be quite crafty:

Stream<String> repeated = Collections.nCopies(5, "RepeatMe").stream();
repeated.forEach(System.out::println); // Why have one when you can have five?
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Behold the Mighty Stream.iterate()

For momentous occasions, when the repetition of values has to follow your rules, the noble .iterate() comes to our aid:

Stream.iterate(1, n -> n + 1).limit(5).forEach(System.out::println); // Customizable advancement at its finest
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The Logic and Beauty of Java 8 Stream Repetition

Java 8's stream capabilities are not just functional - they're elegant. This elegance promotes more efficient and readable code without sacrificing performance.

The Customizable BiConsumer Rides In

A BiConsumer provides a platform for building a custom repeat function when working with actions that need two inputs:

BiConsumer<Integer, Runnable> repeat = (times, action) -> 
    IntStream.range(0, times).forEach(i -> action.run());
repeat.accept(5, () -> System.out.println("BiConsumer Repeat")); // Makes repeating an action as easy as binge-watching Netflix
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Stream.generate With Suppliers: Fresh Values for Every Call

For repeating dynamic or more complex values, use suppliers with Stream.generate():

Supplier<String> dynamicStringSupplier = () -> "Computed " + Math.random();
Stream.generate(dynamicStringSupplier).limit(3).forEach(System.out::println); // Like fortune cookies, but with less crunch
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Unleashing the Horsepower with Parallel Streams

Parallel streams come into play when you find yourself dealing with large sequences. They put all your processor cores to work so you can play Minesweeper while your sequences generate.

Stream<String> parallelRepeats = Collections.nCopies(1_000_000, "RepeatMe").parallelStream();
parallelRepeats.forEach(System.out::println); // Because waiting for loops is so 2005
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Stream Collectors: The Group Photo of Your Results

Collectors let you generate lists or other structures from repeated operations. It's like herding cats, but less furry:

List<Integer> squares = IntStream.range(1, 5)
    .map(n -> n * n)
    .boxed()
    .collect(Collectors.toList()); // Collect 'em all!
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Expert Level: Advanced Repeating in Java 8

Going beyond the basics, Java 8 streams allow for impressive flexibility and customization, fitting a diverse range of specific scenarios.

The Art of Custom Sequences

Java allows you to get fancy with your sequences. If starting at zero or incrementing by one is too mainstream for your sequence, mix things up with .iterate():

IntStream.iterate(10, n -> n + 10).limit(5).forEach(System.out::println); // Because starting at zero is too predictable
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State of the Art: Stateful Operations

Java Stream's .generate() enables your repeated function to maintain continuity between cycles. Retaining your state in Java is easier than in real life.

AtomicInteger counter = new AtomicInteger(0);
Stream.generate(counter::incrementAndGet).limit(5).forEach(System.out::println); // The stream that keeps on giving
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Loop Replacement Therapy

Java 8 streams can replace many traditional loops with a more concise structure. It's like a condensing course in grammar, but for Java.

// Traditional loop
for(String s : listOfStrings) {
    System.out.println(s);
}

// Stream equivalent
listOfStrings.stream().forEach(System.out::println); // Fewer lines, more time for coffee
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Virtual Memory And You

In scenarios where you're concerned about memory usage, the virtual list approach, which creates lazy streams, is a real game-changer:

Stream<String> virtualList = Stream.generate(() -> "I'm virtual").limit(100);
virtualList.forEach(System.out::println); // Our memory usage has entered the virtual realm
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