Overview:

The goal of this enhancement is to improve the efficiency and readability of the filter method by replacing the explicit loop with a more concise and optimized implementation using Collection.removeIf().

Current Implementation: The filter method currently employs an explicit while loop with an Iterator to iterate through the elements of the input collection (c) and remove elements that do not satisfy the provided predicate (p). Although the method correctly filters the collection based on the given predicate, the implementation could be further improved.

Proposed Enhancement: The proposed enhancement suggests refactoring the filter method to take advantage of the Collection.removeIf method, which was introduced in Java 8. This method allows us to efficiently remove elements from the collection that do not satisfy the given predicate in a single operation. The modified code will be more concise and potentially more performant, as it benefits from internal optimizations in the removeIf implementation.

Proposed Implementation:

The enhanced filter method will be modified as follows:

public static Collection filter(Collection c, Predicate p) {
    c.removeIf(o -> !p.evaluate(o));
    return c;
}

Expected Benefits:

  • Improved Readability: The proposed enhancement makes the code more concise and easier to understand by eliminating the explicit loop and iterator operations.

  • Enhanced Performance: The Collection.removeIf method is optimized for removing elements from a collection based on a condition. This should lead to better performance compared to the traditional loop-based approach, especially for large collections.

  • Consistency with Modern Practices: The updated implementation aligns with modern Java practices, leveraging the power of lambda expressions and functional programming features introduced in Java 8 and later versions.

Affects: 6.x

Comment From: sbrannen

Please refrain from opening an issue and a PR for the same topic.

Thanks

  • superseded by #30993