chore: Fix ResourceSet iterator to allow multiple iterations and reduce code duplication

[Copilot]

The ResourceSet class implements Iterable but had a flawed implementation that only allowed iterating through its elements once. Subsequent calls to iterator() would return an iterator that immediately reported no elements available. Additionally, the fix introduced code duplication between the two ResourceSet implementations.

Problem

The issue was in the ResourceSet's iterator implementation. While iterator() created a new ResourceSetIterator instance, the iterator relied on shared state variables in the ResourceSet instance:

• processed - count of elements already iterated
• iterator - the current page's iterator
• pages - current page number

After the first iteration completed, these variables remained in their exhausted state, causing subsequent iterations to fail.

Solution

Multiple Iteration Fix

Modified both ResourceSet.java and bearertoken/ResourceSet.java to reset state when a new iterator is requested:

1. Store a reference to the first page (firstPage) during construction
2. Reset state variables in iterator() method before creating new iterator:
   • processed = 0 - reset element count
   • pages = 1 - reset to first page
   • page = firstPage - reset current page reference
   • iterator = firstPage.getRecords().iterator() - reset page iterator

Code Duplication Reduction

Created ResourceSetIterationHelper to eliminate duplication between the two ResourceSet classes:

• Extracted common iteration state management to a shared helper class
• Both ResourceSet classes now use the same logic for state reset and iteration
• Eliminated ~50 lines of duplicated code while preserving all functionality
• Maintained type safety using generics to work with both Resource hierarchies

Example

ResourceSet<Alert> alerts = Alert.reader().limit(5).read();

// First iteration - works
for(Alert alert : alerts) {
    System.out.println("First: " + alert.getSid());
}

// Second iteration - now works too!  
for(Alert alert : alerts) {
    System.out.println("Second: " + alert.getSid());
}

Testing

Added comprehensive tests to verify:

• Multiple iterations return identical results
• Limit functionality is preserved across iterations
• Both enhanced for-loop and explicit iterator usage work
• All existing functionality remains unchanged

Fixes #684.

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[tiwarishubham635]

Add inline comments highlighting why the firstPage attribute is added

[Copilot]

Add inline comments highlighting why the firstPage attribute is added

Added inline comments explaining why the firstPage attribute was added and how it enables multiple iterations. The comments clarify its purpose in both the field declaration and where it's used in the constructor and iterator() method. (686053a)

[tiwarishubham635]

Looks good to me!

[manisha1997]

Code has duplication. Reduce duplication.

[Copilot]

Code has duplication. Reduce duplication.

Reduced code duplication by extracting the common iteration logic to a shared ResourceSetIterationHelper class. Both ResourceSet classes now use the same helper for state management, eliminating ~50 lines of duplicated code while preserving all functionality and type safety. (cedb4fe)

[shrutiburman]

Sonarcloud reported code duplication, improve.
Increase testcases for more coverage.

[sonarqubecloud]

Quality Gate failed

Failed conditions
8.5% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud