de.ipcon.db.castor

Class FulltextEvaluator

java.lang.Object

de.ipcon.db.castor.MEXTransformerEvaluator

de.ipcon.db.castor.FulltextEvaluator

All Implemented Interfaces:

MEXTransformerEvaluatorI

public class FulltextEvaluator
extends MEXTransformerEvaluator

MEXTransformerEvaluator responsible for parsing and transforming "Fulltext" expressions into "IN LIST" clauses.

This evaluator acts as a bridge between the MEX query and the internal Full-Text Search (FTS) engine. It converts high-level search syntax into a list of primary keys that satisfy the search criteria.

Syntax: {Fulltext [from <ClassName>] matches <SearchTerms>}

Transformation Example:
Input: {Fulltext from Product matches 'blue suede'}
Output: obj.Id IN LIST ('101', '205', '309')

Constructor Summary

Constructors

Constructor and Description
FulltextEvaluator(MEXPersistenceQueryResults _mexQR) Initializes the evaluator with the query results context.

Method Summary

Modifier and Type	Method and Description
boolean	canHandle(java.lang.CharSequence s) Quickly determines if the expression is a Fulltext instruction.
java.lang.CharSequence	evaluate(java.lang.CharSequence s, MEXTransformer transformer) Evaluates the Fulltext expression by invoking the FTS engine and generating an SQL IN-clause.
java.lang.String[]	getGroups(java.lang.CharSequence s) Deconstructs the Fulltext expression into its component parts.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FulltextEvaluator

public FulltextEvaluator(MEXPersistenceQueryResults _mexQR)

Initializes the evaluator with the query results context.

Parameters:

_mexQR - The execution context containing the FTS engine reference.

Method Detail

canHandle

public boolean canHandle(java.lang.CharSequence s)

Quickly determines if the expression is a Fulltext instruction.

Specified by:

canHandle in class MEXTransformerEvaluator

Parameters:

s - The segment of text being evaluated.

Returns:

true if the text starts with the "Fulltext" keyword.

getGroups

public java.lang.String[] getGroups(java.lang.CharSequence s)
                             throws MEXParseException

Deconstructs the Fulltext expression into its component parts.

Parameters:

s - The full expression string.

Returns:

A String array where index 0 is the search clause and index 1 is the class name (may be null).

Throws:

MEXParseException - if the syntax does not match PATTERN_FULLTEXT_FULL.

evaluate

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

Evaluates the Fulltext expression by invoking the FTS engine and generating an SQL IN-clause.

The process follows these steps:

1. Validates that the FTS engine is initialized and active.
2. Extracts the search terms and target entity class.
3. If no class is specified, it infers the entity from the query source.
4. Calls the FTS engine to retrieve a comma-separated string of IDs.
5. Returns a string in the format: obj.id IN LIST ('id1', 'id2', ...).

Specified by:

evaluate in interface MEXTransformerEvaluatorI

Specified by:

evaluate in class MEXTransformerEvaluator

Parameters:

s - The instruction sequence.

transformer - The transformer instance used for source context inference.

Returns:

A CharSequence containing the resolved "IN LIST" clause.

Throws:

MEXUnavailableException - if the FTS engine is offline or unavailable.