org.modeshape.graph.query.process
Class MergeJoinComponent

java.lang.Object
  org.modeshape.graph.query.process.ProcessingComponent
      org.modeshape.graph.query.process.JoinComponent
          org.modeshape.graph.query.process.MergeJoinComponent

@Immutable
public class MergeJoinComponent
extends JoinComponent

Create a processing component that performs a merge-join algorithm. This algorithm only makes sense for equi-joins, child-node joins, and same-node joins.

Note that it is required that the left and right processing components (where this component gets its results) must already be properly sorted and have had duplicates removed.

Nested Class Summary

Nested classes/interfaces inherited from class org.modeshape.graph.query.process.JoinComponent

JoinComponent.Joinable, JoinComponent.TupleMerger, JoinComponent.ValueSelector

Nested classes/interfaces inherited from class org.modeshape.graph.query.process.ProcessingComponent

ProcessingComponent.DynamicOperation

Field Summary

Fields inherited from class org.modeshape.graph.query.process.JoinComponent

LOCATION_COMPARATOR

Constructor Summary

MergeJoinComponent(QueryContext context, ProcessingComponent left, ProcessingComponent right, ChildNodeJoinCondition condition, JoinType joinType)

MergeJoinComponent(QueryContext context, ProcessingComponent left, ProcessingComponent right, EquiJoinCondition condition, JoinType joinType)

MergeJoinComponent(QueryContext context, ProcessingComponent left, ProcessingComponent right, SameNodeJoinCondition condition, JoinType joinType)

Method Summary

List<Object[]>	execute() Execute this stage of processing and return the resulting tuples that each conform to the columns.
protected boolean	isSameTuple(QueryResults.Columns columns, Object[] tuple1, Object[] tuple2)

Methods inherited from class org.modeshape.graph.query.process.JoinComponent

comparatorFor, createMerger, getJoinCondition, getJoinType, joinableFor, left, leftColunns, right, rightColumns, valueSelectorFor

Methods inherited from class org.modeshape.graph.query.process.ProcessingComponent

close, createDynamicOperation, createSortComparator, emptyTuples, getColumns, getContext, problems

Methods inherited from class java.lang.Object

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

Constructor Detail

MergeJoinComponent

public MergeJoinComponent(QueryContext context,
                          ProcessingComponent left,
                          ProcessingComponent right,
                          EquiJoinCondition condition,
                          JoinType joinType)

MergeJoinComponent

public MergeJoinComponent(QueryContext context,
                          ProcessingComponent left,
                          ProcessingComponent right,
                          ChildNodeJoinCondition condition,
                          JoinType joinType)

MergeJoinComponent

public MergeJoinComponent(QueryContext context,
                          ProcessingComponent left,
                          ProcessingComponent right,
                          SameNodeJoinCondition condition,
                          JoinType joinType)

Method Detail

execute

public List<Object[]> execute()

Execute this stage of processing and return the resulting tuples that each conform to the columns.

Specified by:

execute in class ProcessingComponent

Returns:

the list of tuples, where each tuple corresonds to the columns; never null

See Also:

ProcessingComponent.execute()

isSameTuple

protected final boolean isSameTuple(QueryResults.Columns columns,
                                    Object[] tuple1,
                                    Object[] tuple2)