com.metamatrix.query.processor.relational
Class MergeJoinStrategy

java.lang.Object
  com.metamatrix.query.processor.relational.JoinStrategy
      com.metamatrix.query.processor.relational.MergeJoinStrategy

Direct Known Subclasses:

NestedLoopJoinStrategy

public class MergeJoinStrategy
extends JoinStrategy

MergeJoinStrategy supports generalized Full, Left Outer, and Inner Joins (containing non-equi join criteria) as long as there is at least one equi-join criteria Additionally supports Semi and Anti-Semi Joins. These too allow for generalized non-equi join criteria. TODO: when there is no non-equi join criteria matching duplicates from the outer side can be output immediately TODO: semi joins should only output left tuples Support for Intersect and Except is controlled by the grouping flag, which changes comparisons to check for null equality.

Nested Class Summary

static class

MergeJoinStrategy.SortOption

Field Summary

Fields inherited from class com.metamatrix.query.processor.relational.JoinStrategy

joinNode, leftSource, rightSource

Constructor Summary

MergeJoinStrategy(boolean sortLeft, boolean sortRight)

MergeJoinStrategy(MergeJoinStrategy.SortOption sortLeft, MergeJoinStrategy.SortOption sortRight, boolean grouping)

Method Summary

java.lang.Object	clone()
void	close()
protected int	compare(java.util.List leftProbe, java.util.List rightProbe, int[] leftExpressionIndecies, int[] rightExpressionIndecies)
protected boolean	compareToPrevious(com.metamatrix.query.processor.relational.SourceState target)
void	initialize(JoinNode joinNode)
protected void	loadLeft()
protected void	loadRight()
protected java.util.List	nextTuple()
void	setProcessingSortRight(boolean processingSortRight)
java.lang.String	toString()

Methods inherited from class com.metamatrix.query.processor.relational.JoinStrategy

outputTuple

Methods inherited from class java.lang.Object

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

Constructor Detail

MergeJoinStrategy

public MergeJoinStrategy(boolean sortLeft,
                         boolean sortRight)

MergeJoinStrategy

public MergeJoinStrategy(MergeJoinStrategy.SortOption sortLeft,
                         MergeJoinStrategy.SortOption sortRight,
                         boolean grouping)

Method Detail

clone

public java.lang.Object clone()

Specified by:

clone in class JoinStrategy

See Also:

JoinStrategy.clone()

initialize

public void initialize(JoinNode joinNode)
                throws MetaMatrixComponentException

Overrides:

initialize in class JoinStrategy

Throws:

MetaMatrixComponentException

See Also:

JoinStrategy.initialize(com.metamatrix.query.processor.relational.JoinNode)

close

public void close()
           throws TupleSourceNotFoundException,
                  MetaMatrixComponentException

Overrides:

close in class JoinStrategy

Throws:

TupleSourceNotFoundException

MetaMatrixComponentException

See Also:

JoinStrategy.close()

nextTuple

protected java.util.List nextTuple()
                            throws MetaMatrixComponentException,
                                   CriteriaEvaluationException,
                                   MetaMatrixProcessingException

Specified by:

nextTuple in class JoinStrategy

Throws:

MetaMatrixComponentException

CriteriaEvaluationException

MetaMatrixProcessingException

compareToPrevious

protected boolean compareToPrevious(com.metamatrix.query.processor.relational.SourceState target)
                             throws MetaMatrixComponentException,
                                    MetaMatrixProcessingException

Throws:

MetaMatrixComponentException

MetaMatrixProcessingException

compare

protected int compare(java.util.List leftProbe,
                      java.util.List rightProbe,
                      int[] leftExpressionIndecies,
                      int[] rightExpressionIndecies)

loadLeft

protected void loadLeft()
                 throws MetaMatrixComponentException,
                        MetaMatrixProcessingException

Overrides:

loadLeft in class JoinStrategy

Throws:

MetaMatrixComponentException

MetaMatrixProcessingException

See Also:

JoinStrategy.loadLeft()

loadRight

protected void loadRight()
                  throws MetaMatrixComponentException,
                         MetaMatrixProcessingException

Overrides:

loadRight in class JoinStrategy

Throws:

MetaMatrixComponentException

MetaMatrixProcessingException

See Also:

JoinStrategy.loadRight()

setProcessingSortRight

public void setProcessingSortRight(boolean processingSortRight)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()