no.sesat.search.query.token
Interface TokenEvaluationEngine

All Known Implementing Classes:

DeadTokenEvaluationEngineImpl, TokenEvaluationEngineImpl

public interface TokenEvaluationEngine

TokenEvaluationEngine contains state as to what is the current term being tokenised, and the term's sets of known and possible predicates. These sets can be in building process, and provide performance improvement by not having to evaluate the token twice. A TokenEvaluationEngine also provides knowledge about which implementation of TokenEvaluator that can handle a particular token TokenPredicate.

Version:

$Revision: 7225 $

Nested Class Summary

static interface	TokenEvaluationEngine.Context
static interface	TokenEvaluationEngine.State Holder for evaluation state during the engine's evaluation.

Field Summary

static TokenEvaluator	ALWAYS_FALSE_EVALUATOR Evaluator that will return false under all circumstances.
static TokenEvaluator	ALWAYS_TRUE_EVALUATOR Evaluator that will return true under all circumstances.
static TokenEvaluator	DEAD_EVALUATOR Evaluator that will throws an EvaluationException under all circumstances.

Method Summary

boolean	evaluate(TokenPredicate token) The real evaluation method all other evaluate...(..) methods will delegate to.
boolean	evaluateClause(TokenPredicate predicate, Clause clause) Utility method to perform one-off evaluations on clauses from non RunningQuery threads.
boolean	evaluateQuery(TokenPredicate predicate, Query query) Utility method to perform one-off evaluations on queries from non RunningQuery threads.
boolean	evaluateTerm(TokenPredicate predicate, String term) Utility method to perform one-off evaluations on terms from non RunningQuery threads.
TokenEvaluator	getEvaluator(TokenPredicate token) Find or create the TokenEvaluator that will evaluate if given (Token)Predicate is true.
String	getQueryString() The query string we're evaluating.
Site	getSite() The site the evaluation's request is against
TokenEvaluationEngine.State	getState() Getter for property state.
void	setState(TokenEvaluationEngine.State state) Setter for property state.

Field Detail

ALWAYS_FALSE_EVALUATOR

static final TokenEvaluator ALWAYS_FALSE_EVALUATOR

Evaluator that will return false under all circumstances.

ALWAYS_TRUE_EVALUATOR

static final TokenEvaluator ALWAYS_TRUE_EVALUATOR

Evaluator that will return true under all circumstances.

DEAD_EVALUATOR

static final TokenEvaluator DEAD_EVALUATOR

Evaluator that will throws an EvaluationException under all circumstances.

Method Detail

getEvaluator

TokenEvaluator getEvaluator(TokenPredicate token)
                            throws EvaluationException

Find or create the TokenEvaluator that will evaluate if given (Token)Predicate is true.

Parameters:

token -

Returns:

Throws:

EvaluationException - if something goes wrong constructing or finding an appropriate evaluator.

getQueryString

String getQueryString()

The query string we're evaluating. May be null if we're only evaluating a term.

Returns:

getSite

Site getSite()

The site the evaluation's request is against

Returns:

evaluate

boolean evaluate(TokenPredicate token)

The real evaluation method all other evaluate...(..) methods will delegate to.

Parameters:

token -

Returns:

evaluateTerm

boolean evaluateTerm(TokenPredicate predicate,
                     String term)

Utility method to perform one-off evaluations on terms from non RunningQuery threads. Typically used by TokenTransformers or performing evaluations on non-clause oriented strings.

Parameters:

predicate -

term -

Returns:

evaluateClause

boolean evaluateClause(TokenPredicate predicate,
                       Clause clause)

Utility method to perform one-off evaluations on clauses from non RunningQuery threads. Typically used by TokenTransformers or performing evaluations on non-clause oriented strings.

Parameters:

predicate -

clause -

Returns:

evaluateQuery

boolean evaluateQuery(TokenPredicate predicate,
                      Query query)

Utility method to perform one-off evaluations on queries from non RunningQuery threads. Typically used by TokenTransformers or performing evaluations on non-clause oriented strings.

Parameters:

predicate -

query -

Returns:

getState

TokenEvaluationEngine.State getState()

Getter for property state.

Returns:

Value of property state.

setState

void setState(TokenEvaluationEngine.State state)

Setter for property state.

Parameters:

state - New value of property state.