BaseGatewayShardAllocator changes for Assigning the batch of shards

[Gaurav614]

Description

This pull request is part of overall improvement #5098
And mainly is around assignment of batches of shards.

The PR is indirectly dependent on following PRs for overall closure of functionality:
#8742
#8218
#8356
#8746
PSA+RSA changes [yet to be raised]

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/20500/
• CommitID: 37796c1
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[amkhar]

Thanks @Gaurav614 for making this change. Suggested few changes, please apply those to whole PR code.

[github-actions]

Compatibility status:

Checks if related components are compatible with change ddd088f

Incompatible components

Skipped components

Compatible components

Compatible components: [https://github.com/opensearch-project/custom-codecs.git, https://github.com/opensearch-project/neural-search.git, https://github.com/opensearch-project/flow-framework.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/security-analytics.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/opensearch-oci-object-storage.git, https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/reporting.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/ml-commons.git, https://github.com/opensearch-project/sql.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/performance-analyzer.git]

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/24556/
• CommitID: 20e11a4
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/26438/
• CommitID: 1a043e7
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[amkhar]

LGTM, spotless apply will be applied after dependent PRs are merged.

[github-actions]

❌ Gradle check result for 1ca219c: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for b230d16: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[khushbr]

LGTM!

[github-actions]

❌ Gradle check result for 1feb844: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 272b972: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[amkhar]

❌ Gradle check result for 272b972: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

testAdmissionControlRejectionEnforcedMode
testAdmissionControlRejectionMonitorOnlyMode

Flaky tests : #12664

[github-actions]

✅ Gradle check result for ddd088f: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 9.09091% with 20 lines in your changes are missing coverage. Please review.

Project coverage is 71.28%. Comparing base (b15cb0c) to head (ddd088f).
Report is 30 commits behind head on main.

Files	Patch %	Lines
.../opensearch/gateway/BaseGatewayShardAllocator.java	9.09%	20 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8776      +/-   ##
============================================
- Coverage     71.42%   71.28%   -0.14%     
- Complexity    59978    60032      +54     
============================================
  Files          4985     4991       +6     
  Lines        282275   282657     +382     
  Branches      40946    40993      +47     
============================================
- Hits         201603   201502     -101     
- Misses        63999    64443     +444     
- Partials      16673    16712      +39     

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