[GitHub] [pulsar] alpreu opened a new issue, #16959: PIP-197: Add Schema hash and equals to public API

[GitBox <gi...@apache.org>]

alpreu opened a new issue, #16959:
URL: https://github.com/apache/pulsar/issues/16959

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   ## Motivation
   
   Currently, the `Schema` interface in the public client-api does not provide access to a sensible hash function. The fallback to Java’s object-equality makes it unfit for use in most hash-based collections. For example, it prevents usage as a key in a cache.
   Further, the lack of a reliable equals function means that there is no way to identify if two schemas are the same thing.  
   
   ## Goal
   
   The goal of this proposal is to provide a sensible `hashCode` and `equals` implementation for Schema as part of the public API. 
   
   Currently, pulsar-common contains `SchemaHash`, a wrapper class that exists to solve the aforementioned problems. However, `SchemaHash` is not part of the public API, so users should not depend on it.
   
   
   ## API Changes
   
   There is no further change required as moving `SchemaHash` from pulsar-common to the public API. The only further change could be to re-think the class name, as the wrapper offers more than just a schemas hash. 
   
   ## Implementation
   
   Move `SchemaHash` from pulsar-common `org.apache.pulsar.common.protocol.schema` package into pulsar-client-api `org.apache.pulsar.common.schema` package. 
   
   
   ## Reject Alternatives
   
   Providing default methods for `equals` and `hashCode` directly on the `Schema` interface is not possible because Java prohibits overriding the base Object methods.
   Another option would be to provide the `hashCode` and `equals` functionality through similarly-named default methods that could be used by any `Schema` implementation. The drawback of this idea is that it requires developers to override the equals and hashCode to use these provided methods, as well as possibly polluting the interface.
   
   


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[GitHub] [pulsar] github-actions[bot] commented on issue #16959: PIP-197: Add Schema hash and equals to public API

[GitBox <gi...@apache.org>]

github-actions[bot] commented on issue #16959:
URL: https://github.com/apache/pulsar/issues/16959#issuecomment-1242849729

   The issue had no activity for 30 days, mark with Stale label.


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