de.ipcon.db.mex

Interface MEXTransformerEvaluatorI

All Known Implementing Classes:

BOTIdListEvaluator, FulltextEvaluator, IdListEvaluator, MEXTransformerEvaluator, PrefetchEvaluator, UnionEvaluator, VariableDefinitionEvaluator, VariableExpansionEvaluator, WithInterfaceEvaluator

public interface MEXTransformerEvaluatorI

Defines the contract for an evaluator component used by the MEXTransformer to process and potentially replace content found within curly brace expressions.

Implementations of this interface are responsible for both recognizing a specific expression type (like variable definitions, unions, or full-text expansions) and executing the necessary replacement or side-effect logic.

The core contract follows a Chain of Responsibility pattern: an evaluator performs a single step of recognition. If the content matches its specialized logic, it returns the replacement; otherwise, it returns the original object to allow the next evaluator in the chain to attempt processing.

Method Summary

Modifier and Type	Method and Description
java.lang.CharSequence	evaluate(java.lang.CharSequence s, MEXTransformer transformer) Attempts to evaluate the content of a curly brace block and determine a replacement value.

Method Detail

evaluate

java.lang.CharSequence evaluate(java.lang.CharSequence s,
                                MEXTransformer transformer)

Attempts to evaluate the content of a curly brace block and determine a replacement value.

The method must adhere to the following logic:

1. Match: Analyze the input s to see if it matches the evaluator's specific expression pattern (e.g. starts with a specific keyword like @union or @prefetch).
2. Evaluate & Replace: If a match is found, perform the transformation or any necessary side effects (e.g. updating parameters in the transformer or registering metadata in the results) and return the replacement CharSequence (which can be an empty string).
3. Skip: If no match is found, the original s object MUST be returned. This signals to the MEXTransformer that the block remains unprocessed, and it will be passed to the next evaluator in the sequence.

Parameters:

s - The CharSequence containing the raw content found inside the original curly brace block (without the surrounding braces).

transformer - The processing MEXTransformer instance, providing access to the transformation context, such as variables or the underlying query state.

Returns:

The replacement CharSequence (including empty strings) if processed; otherwise, the exact original object s.