GeneratorCachingIteratorAggregate

Class
extends CountableIteratorAggregate

A caching iterator aggregate designed to wrap a generator and cache its results.

Description

This class allows wrapping a Generator or a callable returning a generator, caching its values to enable multiple iterations over the same dataset.

Usage Example:

Tags
example

Description

Using a Generator

use FastForward\Iterator\GeneratorCachingIteratorAggregate;

$iterator = new GeneratorCachingIteratorAggregate(
    (function () {
        yield 'A';
        yield 'B';
        yield 'C';
    })()
);

foreach ($iterator as $value) {
    echo $value; // Outputs: A B C
}

foreach ($iterator as $value) {
    echo $value; // Outputs: A B C (cached)
}
example

Description

Using a Callable that Returns a Generator

use FastForward\Iterator\GeneratorCachingIteratorAggregate;

$iterator = new GeneratorCachingIteratorAggregate(fn () => (function () {
    yield 1;
    yield 2;
    yield 3;
})());

foreach ($iterator as $value) {
    echo $value; // Outputs: 1 2 3
}

foreach ($iterator as $value) {
    echo $value; // Outputs: 1 2 3 (cached)
}

Note: If a callable is provided, it is automatically converted to a generator using ClosureFactoryIteratorAggregate.

since
1.0.0

Table of Contents

Properties

$cachingIterator
 : CachingIterator

Methods

__construct()

Initializes the caching iterator with a generator or a callable returning a generator.

 : mixed
count()

Counts the number of elements exposed by the inner iterator.

 : int
getIterator()

Retrieves the iterator, either from the cache or the generator itself.

 : Traversable
Properties

$cachingIterator

Private Read-only
private CachingIterator $cachingIterator

Description

the caching iterator that stores generated values

Methods

__construct()

Public

Initializes the caching iterator with a generator or a callable returning a generator.

public __construct( callable|Generator  $generator) : mixed

Description

If a callable is provided, it is wrapped in a ClosureFactoryIteratorAggregate to generate the iterator.

Parameters
$generator : callable|Generator

Description

the generator or a callable returning a generator

count()

Public

Counts the number of elements exposed by the inner iterator.

public count() : int

Description

If the inner iterator implements Countable, this method SHALL return the value provided by that implementation. Otherwise, it MUST count elements by iterating over the iterator. If the inner iterator is not cloneable, this method SHALL wrap the current object in an IteratorIterator instance and count through that wrapper to avoid performing an invalid clone operation. If the inner iterator is cloneable, this method SHOULD count over a clone so that the original iterator state is preserved as much as possible.

Return values
int

Description

the total number of elements available from the inner iterator

getIterator()

Public

Retrieves the iterator, either from the cache or the generator itself.

public getIterator() : Traversable

Description

This method ensures that once a generator is iterated, its values remain available for subsequent iterations.

Return values
Traversable

Description

the cached or fresh iterator