Error Codes¶

All Mustang runtime errors are thrown as MustangException with a typed ErrorCode.

import com.phonepe.mustang.exception.MustangException;
import com.phonepe.mustang.exception.ErrorCode;

try {
    engine.add("my-index", criteria);
} catch (MustangException e) {
    ErrorCode code = e.getErrorCode();
    // handle
}

Error Code Reference¶

`ErrorCode`	When thrown	Resolution
`CRITERIA_NOT_FOUND`	`delete()` called for a criteria ID that is not indexed	Verify the criteria ID exists in the index before deleting
`DUPLICATE_CRITERIA`	`add()` called with a criteria ID that is already indexed	Use `update()` to modify an existing criteria
`INDEX_NOT_FOUND`	Operation on an index group that does not exist	Ensure the index has been populated with `add()` before searching or replacing
`INVALID_CRITERIA`	Criteria is structurally invalid (e.g. empty conjunctions/disjunctions)	Validate that all required fields are present and non-empty
`SERIALIZATION_ERROR`	`exportIndexGroup()` / `importIndexGroup()` serialization failure	Check the ObjectMapper configuration; ensure all types are registered
`EVALUATION_ERROR`	Error during predicate evaluation (e.g. attribute path not found, type mismatch)	Verify that attribute paths (`lhs`) are valid JSONPath expressions and the event schema matches

MustangException Fields¶

public class MustangException extends RuntimeException {
    ErrorCode errorCode;   // typed error code
    String message;        // human-readable description
    Throwable cause;       // underlying cause (may be null)
}

Dropwizard Bundle Error Responses¶

When using mustang-dw-bundle, all exceptions are mapped to HTTP responses by MustangExceptionMapper:

`ErrorCode`	HTTP Status
`CRITERIA_NOT_FOUND`	`404 Not Found`
`DUPLICATE_CRITERIA`	`409 Conflict`
`INDEX_NOT_FOUND`	`404 Not Found`
`INVALID_CRITERIA`	`400 Bad Request`
`SERIALIZATION_ERROR`	`500 Internal Server Error`
`EVALUATION_ERROR`	`422 Unprocessable Entity`

Response body follows MustangResponse format:

{
  "status": "ERROR",
  "errorCode": "DUPLICATE_CRITERIA",
  "message": "Criteria with id 'rule-001' already exists in index 'my-index'"
}