IBX-719: Introduced BatchIterator

[adamwojs]

Question	Answer
JIRA issue	https://issues.ibexa.co/browse/IBX-719
Type	feature
Target eZ Platform version	v3.3
BC breaks	no
Doc needed	yes

BatchIterator allows iterate over result sets (e.g. content objects, locations) which cannot be loaded into memory at once.

Examples from existing code base:

ezplatform-kernel/eZ/Bundle/EzPublishCoreBundle/Command/CheckURLsCommand.php

Lines 90 to 108 in 4c84074

	$query = new URLQuery();
	$query->filter = new Criterion\VisibleOnly();
	$query->sortClauses = [
	new SortClause\URL(),
	];
	$query->offset = 0;
	$query->limit = $limit;
	$totalCount = $this->getTotalCount();
	$progress = new ProgressBar($output, $totalCount);
	$progress->start();
	while ($query->offset < $totalCount) {
	$this->urlChecker->check($query);
	$progress->advance(min($limit, $totalCount - $query->offset));
	$query->offset += $limit;
	}
	$progress->finish();

ezplatform-kernel/eZ/Bundle/EzPublishCoreBundle/Command/ResizeOriginalImagesCommand.php

Lines 210 to 220 in 4c84074

	while ($query->offset <= $totalCount) {
	$results = $this->searchService->findContent($query);
	/** @var \eZ\Publish\API\Repository\Values\Content\Search\SearchHit $hit */
	foreach ($results->searchHits as $hit) {
	$this->resize($output, $hit, $imageFieldIdentifier, $filter);
	$progressBar->advance();
	}
	$query->offset += $iterationCount;
	}

Usage

$filter = new Filter();
// ... add criteria, sort clauses etc.

$iterator = new BatchIterator(new ContentFilteringAdapter($contentService, $filter));
foreach ($iterator as $content) {
   // process content object
}

Available adapters

All built-in adapters are places under \eZ\Publish\API\Repository\Iterator\BatchIteratorAdapter\ namespace.

Adapter	Method
ContentFilteringAdapter	\eZ\Publish\API\Repository\ContentService::find
ContentInfoSearchAdapter	\eZ\Publish\API\Repository\SearchService::findContentInfo
ContentSearchAdapter	\eZ\Publish\API\Repository\SearchService::findContent
LocationFilteringAdapter	\eZ\Publish\API\Repository\LocationService::find
LocationSearchAdapter	\eZ\Publish\API\Repository\SearchService::findLocations

Checklist:

• Provided PR description.
• Tested the solution manually.
• Provided automated test coverage.
• Checked that target branch is set correctly (master for features, the oldest supported for bugs).
• Ran PHP CS Fixer for new PHP code (use $ composer fix-cs).
• Asked for a review (ping @ezsystems/php-dev-team).

[adamwojs]

PR updated according to code review suggestions.

[Steveb-p]

Added language phpdocs based on usage found in PR.

👍

[Steveb-p]

I think sonar code style checks can be discarded: it complains that a local variable has the same name as class property.

[ViniTou]

Does it need to be public?

[adamwojs]

No, but there is valid use case to keep it public. See https://github.com/ibexa/installer/pull/30/commits/50841b962bc2e666cf0036b11738a5503ad44d1e

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[Steveb-p]

Both code smells detected by SonarCloud should probably be marked as "won't fix", since they are about variable that shares the name with property that they are cloned from.

[micszo]

QA Approved on Ibexa Experience 3.3.6-dev with branch.