Fix cache implementation in MultiDelimiterStringSearchInterpolator and RegexBasedInterpolator

[Copilot]

Problem

The cacheAnswers setting in both MultiDelimiterStringSearchInterpolator and RegexBasedInterpolator had no effect. While the code attempted to read from the existingAnswers cache, it never populated the cache with resolved values, making the cache optimization completely ineffective.

Solution

Added the missing cache population logic that stores resolved values into existingAnswers when cacheAnswers is enabled. This brings both interpolators in line with the implementation pattern used in StringSearchInterpolator.

Code change applied to both classes:

if (cacheAnswers) {
    existingAnswers.put(realExpr, value);
}

Impact

Users who enable caching via setCacheAnswers(true) will now see significant performance improvements when interpolating strings with repeated expressions:

• Before fix: Cache had no effect - expressions were re-evaluated on every interpolate() call
• After fix: First occurrence is evaluated and cached; subsequent calls use the cached value

Example improvement for MultiDelimiterStringSearchInterpolator:

interpolator.setCacheAnswers(true);
// Input: "${key}-${key}-${key}-${key}"
// Before: 8 ValueSource lookups (per interpolate call)
// After:  1 ValueSource lookup (first call), 0 lookups (subsequent calls)

Example improvement for RegexBasedInterpolator:

interpolator.setCacheAnswers(true);
// Input: "${key}-${key}-${key}-${key}"
// Before: 1 ValueSource lookup per interpolate() call
// After:  1 ValueSource lookup (first call), 0 lookups (subsequent calls)

Testing

• Added comprehensive test coverage for both cached and non-cached scenarios in both interpolator classes
• All 138 tests pass (134 existing + 4 new)
• CodeQL security scan: no vulnerabilities detected

Files Changed

• MultiDelimiterStringSearchInterpolator.java: Added cache population (4 lines)
• MultiDelimiterStringSearchInterpolatorTest.java: Added 2 tests (58 lines)
• RegexBasedInterpolator.java: Added cache population (4 lines)
• RegexBasedInterpolatorTest.java: Added 2 tests (69 lines)

Fixes #19

Original prompt

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This section details on the original issue you should resolve

<issue_title>MultiDelimiterStringSearchInterpolator does not cache answers</issue_title>
<issue_description>MultiDelimiterStringSearchInterpolator's cacheAnswers has no effect at all, since existingAnswers Map is never populated.</issue_description>

Comments on the Issue (you are @copilot in this section)

@slawekjaranowski similar to: - #20 @slawekjaranowski maybe we can drop at all `cacheAnswers`, as source are in many time a maps in memory why we need build another map

Fixes #19

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[slachiewicz]

@copilot RegexBasedInterpolator also needs similar optimalizaton #20

[Copilot]

@copilot RegexBasedInterpolator also needs similar optimalizaton #20

Fixed in commit dadb1e8. Applied the same cache population pattern to RegexBasedInterpolator - added 4 lines to populate existingAnswers when cacheAnswers is true, plus comprehensive test coverage.