feat: use property syntax all the properties that are persisted

[1abhishekpandey]

Description

• We have provided getters for all properties, including userId, traits, and anonymousId, that persist in storage (excluding externalId as in future we are going to remove its persistence). Also, we've added a setter to set only the anonymousId.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactor/optimization

Implementation Details

• We have added getters for all the properties that are persisted and setters only for the anonymousId, as userId and traits can be set while making the identify event. I've not provided the option to get the externalId, as we've decided to remove the persistence for this value in future PR.
• I've added them as an extension function in the UserIdentity class itself, where those variables have been defined.
• They can make a call like this:

// Settter
RudderAnalyticsUtils.analytics.anonymousId = "Custom Anonymous ID"
// Getter
val anonymousId = RudderAnalyticsUtils.analytics.anonymousId
val userId = RudderAnalyticsUtils.analytics.userId
val traits = RudderAnalyticsUtils.analytics.traits

• I've added buttons to set and fetch these properties.
• Added unit tests.

Checklist

• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation (if appropriate).
• I have ensured that my code follows the project's code style.
• I have checked for potential performance impacts and optimized if necessary.
• I have checked the code for security issues.
• I have updated the changelog (if required).

How to test?

• Use the above code snippet or buttons provided in the sample app and you can see the value being fetched and set.
• anonymousId:
  • After SDK init, get the anonymousId: It'll return the UUID v4.
  • Call shutdown, and then get the anonymousId: It'll return null.
  • Set the anonymousId, and then get the anonymousId: It'll return the custom anonymousId.
• userId and traits:
  • After SDK init, get the userId and traits: It'll return empty values.
  • Make and identify the event and set both the values, and then try to get them: It'll return the set values.
  • Call shutdown, and then get them: It'll return null.

Breaking Changes

• We have removed the getAnonymousId and setAnonymousId APIs defined in the Analytics class. Now, the user needs to access this as a property. Now, this is no longer valid:

val anonymousId = analytics.getAnonymousId()
analytics.setAnonymousId("<custom_anonymousId>")

Maintainers Checklist

• The code has been reviewed.
• CI tests have passed.
• All necessary documentation has been updated.

Screenshots (if applicable)

Before:

After:

Additional Context

NOTE: We've not added getters for externalId, as we've planned to remove storage support for that property.

[vgupta98]

I noticed that when we have extension property like this, we are unable to access getter and setter for this field in a java class making it java incompatible. We have to define them as class level property in this case.

[vgupta98]

NIT: we can use assertEquals instead of assertTrue at some places.