HDDS-16039. Introduce S3StorageClass mapping to OzoneStoragePolicy.

[devmadhuu]

What changes were proposed in this pull request?

This PR is to introduce S3StorageClass — a small enum that maps AWS S3 storage class strings (STANDARD, STANDARD_IA, GLACIER) to Ozone storage policies (HOT, WARM, COLD).

Two helper methods on the enum:

• fromS3StorageClass(String) — parse the value of an incoming x-amz-storage-class header.
• fromStoragePolicy(StoragePolicy) — go the other way, for building responses.

This PR is infrastructure only — no caller uses S3StorageClass yet. The S3 write path (PutObject) and read path (GetObject) will start calling it in follow-up PRs.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-16039

How was this patch tested?

New unit test TestS3StorageClass covers:

• S3 string → enum for all three values, plus rejects null and unknown values.
• Ozone StoragePolicy → enum for all three, plus rejects null.
• Round-trip consistency across all enum values.

[F64116045]

Thanks @devmadhuu.
I wonder would Locale.ROOT be safer here? toUpperCase() uses the JVM's default locale.
For example, under Turkish locale, "standard_ia" becomes "STANDARD_İA", which does not match the enum constant.
The Java documentation recommends Locale.ROOT for locale-independent strings such as protocol keys.

[Gargi-jais11]

+1

[Gargi-jais11]

Thanks @devmadhuu for this PR.

[Gargi-jais11]

I don't know whether u are aware or not but S3StorageType.java in the S3 Gateway has similar enums means: “this S3 storage class string picks how many copies / EC layout the object gets” (STANDARD → 3-way Ratis, STANDARD_IA → EC, etc.). Almost all upload/download code uses that today.

This PR adds S3StorageClass, which means: “this string picks Hot / Warm / Cold (which disk tier).”

Those are two different ideas with similar names. That will confuse people and cause wrong imports later.

We should look into these and check how they both can be used independently.

[xichen01]

AWS's StorageClass https://aws.amazon.com/s3/storage-classes does not explicitly specify the replica types or storage media types for each StorageClass; instead, it defines concepts such as durability, SLA, zones, and latency , etc for different StorageClasses

Ozone’s S3 StorageClasses can have custom definitions; users can specify the storage medium (storage policy) and replica type through S3 StorageClass parameter, which does not conflict with AWS S3’s StorageClasses.

[Gargi-jais11]

IllegalArgumentException is fine for a util with no callers yet but PutObject must map unknown classes to OS3Exception / InvalidStorageClass, not a 500.