# Package org.eclipse.rdf4j.query.algebra.evaluation

- Interface Summary
  Interface | Description
  --- | ---
  EvaluationStrategy | Evaluates `TupleExpr`s and `ValueExpr`s.
  EvaluationStrategyFactory | Factory for `EvaluationStrategy`s.
  QueryContextInitializer | Callback for configuring/customising a `QueryContext`.
  QueryOptimizer | Interface used by `StrictEvaluationStrategy` prior to evalutating the query.
  QueryPreparer | A generic interface for executing queries over a `TripleSource`.
  TripleSource | A triple source that can be queried for (the existence of) certain triples in certain contexts.

- Class Summary
  Class | Description
  --- | ---
  AbstractQueryPreparer |
  QueryBindingSet | An implementation of the `BindingSet` interface that is used to evalate query object models.
  QueryContext | A `QueryContext` provides a means to pass arbitrary local state to a `Function` or `TupleFunction`.

- Exception Summary
  Exception | Description
  --- | ---
  ValueExprEvaluationException | An exception indicating that a `ValueExpr` could not be evaluated due to illegal or incompatible values.

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