Java 8 forEach with index

Pattern party– Dance with indices in forEach

Index management: Array is the new 'in' thing

final int[] index = new int[]{0};
list.forEach(e -> {
    // Your operation here
    System.out.println("Elemento numero " + e + " at index " + index[0]++ + ". Bam!"); //Who knew indices could dance salsa?
});


This pattern maneuvers around mutable index tracking while maintaining the black-tie elegance of forEach.

forEachOrdered: A waltz with order

Parallel streams are a wild party. To preserve the encounter order while iterating, play gentle music with forEachOrdered:

list.parallelStream().forEachOrdered(e -> {
    // Your well-ordered operations here
});


This ensures a choreographed dance, regardless of the DJ's choice of thread.

Libraries: Your ultimate party planners

Libraries like Apache Commons Lang pump up the volume on Java's index functionality:

IterableUtils.forEach(list, (index, element) -> {
    // Dance with index and element
});


These libraries add an abstraction layer to hide index management's messy room.

Battle royal: Traditional loops vs. Stream

Classic for loop: Oldie but a goodie

Offers straightforward index access:

for (int i = 0; i < list.size(); i++) {
    // i as the index, clear as mud!
}


It's a hard-hitting champion in cases where index manipulation is integral.

Stream: Amazing grace with an Achilles' heel

Streams are highbrow, but lacks a built-in index support. If index access becomes the celebrity guest, the traditional loop gets the VIP pass.

Concurrency: Where forEach shines

With read-only operations on a concurrent collection, using a forEach pattern ensures you're on the safe lane:

list.parallelStream().forEach(element -> {
    // Concurrency-safe read operations
});


Today's multi-threaded party demands a bouncer. And forEach is your guy!

Performance: For whom the bell tolls

Between streams and traditional loops, bets are high. The winner might be decided by the size of your data and how you parallelize:

// Parallel processing for potential performance pump-up
list.parallelStream().forEach(element -> {
    // Your beefed-up operations here
});


Choosing the fighter wisely is key or else it could sting like a bee!