# 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 `EvaluationStrategy`s to optimize the `TupleExpr` prior to evaluating the query.
  QueryOptimizerPipeline | A pipeline of `QueryOptimizer`s that, when executed in order on a `TupleExpr`, convert that `TupleExpr` to a more optimal query execution plan.
  QueryPreparer | A generic interface for executing queries over a `TripleSource`.
  RDFStarTripleSource |
  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.