org.eigenbase.rel
Class SortRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel
          org.eigenbase.rel.SortRel

All Implemented Interfaces:

Cloneable, RelNode

public final class SortRel
extends SingleRel

Relational expression which imposes a particular sort order on its input without otherwise changing its content.

Field Summary

protected RelFieldCollation[]	collations
protected RexNode[]	fieldExps

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

SortRel(RelOptCluster cluster, RelNode child, RelFieldCollation[] collations)
Creates a sorter.

Method Summary

SortRel	clone() Clones this RelNode.
void	explain(RelOptPlanWriter pw)
RexNode[]	getChildExps() Returns an array of this relational expression's child expressions (not including the inputs returned by RelNode.getInputs().
RelFieldCollation[]	getCollations()

Methods inherited from class org.eigenbase.rel.SingleRel

childrenAccept, deriveRowType, getChild, getInputs, getRows, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

collations

protected final RelFieldCollation[] collations

fieldExps

protected final RexNode[] fieldExps

Constructor Detail

SortRel

public SortRel(RelOptCluster cluster,
               RelNode child,
               RelFieldCollation[] collations)

Creates a sorter.

Parameters:

cluster - RelOptCluster this relational expression belongs to

child - input relational expression

collations - array of sort specifications

Method Detail

clone

public SortRel clone()

Description copied from interface: RelNode

Clones this RelNode.

Traits of the RelNode must be explicitly cloned, using AbstractRelNode.inheritTraitsFrom(AbstractRelNode), as the RelNode may have traits of which it has no knowledge. Example implementation:

     public MyRelNode clone()
     {
         MyRelNode clone = new MyRelNode(...);
         clone.inheritTraitsFrom(this);
         return clone;
     }
 

N.B.: This method must be overridden whenever an existing, concrete RelNode is extended. Otherwise, calling clone() will produce a differently typed RelNode, resulting in invalid or incorrect query plans.

Specified by:

clone in interface RelNode

Specified by:

clone in class AbstractRelNode

Returns:

a clone of this RelNode

getChildExps

public RexNode[] getChildExps()

Description copied from interface: RelNode

Returns an array of this relational expression's child expressions (not including the inputs returned by RelNode.getInputs(). If there are no child expressions, returns an empty array, not null.

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

getCollations

public RelFieldCollation[] getCollations()

Returns:

array of RelFieldCollations, from most significant to least significant

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class SingleRel