## Uses of Class
org.eclipse.rdf4j.common.iteration.LookAheadIteration

- Packages that use LookAheadIteration
  Package | Description
  --- | ---
  org.eclipse.rdf4j.common.iteration |
  org.eclipse.rdf4j.federated.evaluation.concurrent |
  org.eclipse.rdf4j.federated.evaluation.iterator |
  org.eclipse.rdf4j.federated.evaluation.join |
  org.eclipse.rdf4j.federated.evaluation.union |
  org.eclipse.rdf4j.query.algebra.evaluation.federation |
  org.eclipse.rdf4j.query.algebra.evaluation.iterator |
  org.eclipse.rdf4j.query.impl |
  org.eclipse.rdf4j.repository.sparql.federation |
  org.eclipse.rdf4j.sail.base | Base functionality for Sail implementations that require multi-versioned concurrency control (MVCC).
  org.eclipse.rdf4j.sail.extensiblestore | Elasticsearch store for string triples
  org.eclipse.rdf4j.sail.memory.model |

- - ### Uses of LookAheadIteration in org.eclipse.rdf4j.common.iteration

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.common.iteration
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `QueueIteration<E,​T extends Exception>` | Makes working with a queue easier by adding the methods `QueueIteration.done()` and `QueueIteration.toss(Exception)` and after converting the Exception to the required type using `QueueIteration.convert(Exception)`.
    `class` | `UnionIteration<E,​X extends Exception>` | An Iteration that returns the bag union of the results of a number of Iterations.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.concurrent

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.concurrent
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `FedXQueueCursor<T>` | Specialized variants of `QueueCursor` which avoids converting any exception if it is already of type`QueryEvaluationException`.
    `class` | `ParallelExecutorBase<T>` | Base class for common parallel executors such as `JoinExecutorBase` and `UnionExecutorBase`.
    `class` | `ParallelServiceExecutor` | Parallel executor for `FedXService` nodes, which wrap SERVICE expressions.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.iterator

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.iterator
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `FederatedDescribeIteration` | Specialized `DescribeIteration` for evaluation of DESCRIBE queries in the federation.
    `class` | `IndependentJoingroupBindingsIteration` | Inserts original bindings into the result.
    `class` | `IndependentJoingroupBindingsIteration2` | Inserts original bindings into the result.
    `class` | `IndependentJoingroupBindingsIteration3` | Inserts original bindings into the result.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.join

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.join
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `ControlledWorkerBoundJoin` | Execute the nested loop join in an asynchronous fashion, using grouped requests, i.e.
    `class` | `ControlledWorkerJoin` | Execute the nested loop join in an asynchronous fashion, i.e.
    `class` | `ControlledWorkerLeftJoin` | Execute the nested loop join in an asynchronous fashion, i.e.
    `class` | `HashJoin` | Operator for a hash join of tuple expressions.
    `class` | `JoinExecutorBase<T>` | Base class for any join parallel join executor.
    `class` | `SynchronousBoundJoin` | Execute the nested loop join in a synchronous fashion, using grouped requests, i.e.
    `class` | `SynchronousJoin` | Execute the nested loop join in a synchronous fashion, i.e.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.union

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.federated.evaluation.union
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `ControlledWorkerUnion<T>` | Execution of union tasks with `ControlledWorkerScheduler`.
    `class` | `SynchronousWorkerUnion<T>` | Synchronous execution of union tasks, i.e.
    `class` | `UnionExecutorBase<T>` | Base class for any parallel union executor.
    `class` | `WorkerUnionBase<T>` | Base class for worker unions providing convenience functions to add tasks.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.query.algebra.evaluation.federation

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.query.algebra.evaluation.federation
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `JoinExecutorBase<T>` | Deprecated. since 2.3 use `JoinExecutorBase`
    `class` | `ServiceCrossProductIteration` | Deprecated.
    `class` | `ServiceJoinIterator` | Iterator for efficient SERVICE evaluation (vectored).

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.query.algebra.evaluation.iterator

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.query.algebra.evaluation.iterator
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `BadlyDesignedLeftJoinIterator` |
    `class` | `BottomUpJoinIterator` | Deprecated. replaced by HashJoinIteration
    `class` | `CrossProductIteration` | Iteration which forms the cross product of a list of materialized input bindings with each result obtained from the inner iteration.
    `class` | `DescribeIteration` | Iteration that implements a simplified version of Symmetric Concise Bounded Description (omitting reified statements).
    `class` | `HashJoinIteration` | Generic hash join implementation suitable for use by Sail implementations.
    `class` | `JoinIterator` | Interleaved join iterator.
    `class` | `LeftJoinIterator` |
    `class` | `MultiProjectionIterator` |
    `class` | `PathIteration` |
    `class` | `ZeroLengthPathIteration` |

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.query.impl

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.query.impl
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `QueueCursor<E>` | Makes working with a queue easier by adding the methods `QueueIteration.done()` and `QueueIteration.toss(Exception)` and automatically converting the exception into a QueryEvaluationException with an appropriate stack trace.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.repository.sparql.federation

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.repository.sparql.federation
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `JoinExecutorBase<T>` | Base class for any join parallel join executor.
    `class` | `SPARQLCrossProductIteration` | Iteration which forms the cross product of a list of materialized input bindings with each result obtained from the inner iteration.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.sail.base

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.sail.base
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `DistinctModelReducingUnionIteration` | An Iteration that takes two source.

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.sail.extensiblestore

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.sail.extensiblestore
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `FilteringIteration<E extends ExtensibleStatement,​X extends Exception>` | A wrapper for an Iteration that filters the statements against a pattern similar to getStatements(Resource subject, IRI predicate, Value object, Resource...

  - ### Uses of LookAheadIteration in org.eclipse.rdf4j.sail.memory.model

    Subclasses of LookAheadIteration in org.eclipse.rdf4j.sail.memory.model
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `MemStatementIterator<X extends Exception>` | A StatementIterator that can iterate over a list of Statement objects.