Class FennelRenameRel

  extended by org.eigenbase.rel.AbstractRelNode
      extended by org.eigenbase.rel.SingleRel
          extended by net.sf.farrago.fennel.rel.FennelSingleRel
              extended by net.sf.farrago.fennel.rel.FennelRenameRel
All Implemented Interfaces:
Cloneable, FennelRel, RelNode

public class FennelRenameRel
extends FennelSingleRel

FennelRenameRel is the Fennel implementation of a rename-only relational Project operator (which is a no-op). It can work with any Fennel calling convention.

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/ $
John V. Sichi

Field Summary
private  String[] fieldNames
Fields inherited from class org.eigenbase.rel.AbstractRelNode
digest, id, rowType, traits
Fields inherited from interface net.sf.farrago.query.FennelRel
Fields inherited from interface org.eigenbase.rel.RelNode
Constructor Summary
FennelRenameRel(RelOptCluster cluster, RelNode child, String[] fieldNames, RelTraitSet traits)
          Creates a new FennelRenameRel object.
Method Summary
 FennelRenameRel clone()
          Clones this RelNode.
 RelOptCost computeSelfCost(RelOptPlanner planner)
          Returns the cost of this plan (not including children).
 RelDataType deriveRowType()
 void explain(RelOptPlanWriter pw)
 boolean isDistinct()
          Returns whether the same value will not come out twice.
 FemExecutionStreamDef toStreamDef(FennelRelImplementor implementor)
          Converts this relational expression to FemExecutionStreamDef form.
Methods inherited from class net.sf.farrago.fennel.rel.FennelSingleRel
getCollations, getFarragoTypeFactory, implementFennelChild
Methods inherited from class org.eigenbase.rel.SingleRel
childrenAccept, getChild, getInputs, getRows, replaceInput
Methods inherited from class org.eigenbase.rel.AbstractRelNode
cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.eigenbase.rel.RelNode
childrenAccept, collectVariablesSet, collectVariablesUsed, getChildExps, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getInputs, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraits, getVariablesStopped, isAccessTo, isValid, onRegister, recomputeDigest, registerCorrelVariable, replaceInput, setCorrelVariable

Field Detail


private String[] fieldNames
Constructor Detail


public FennelRenameRel(RelOptCluster cluster,
                       RelNode child,
                       String[] fieldNames,
                       RelTraitSet traits)
Creates a new FennelRenameRel object.

cluster - RelOptCluster for this rel
child - input rel whose fields are to be renamed
fieldNames - new field names
traits - traits for this rel
Method Detail


public boolean isDistinct()
Description copied from interface: RelNode
Returns whether the same value will not come out twice. Default value is false, derived classes should override.

Specified by:
isDistinct in interface RelNode
isDistinct in class AbstractRelNode


public FennelRenameRel 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(...);
         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
a clone of this RelNode


public RelOptCost computeSelfCost(RelOptPlanner planner)
Description copied from interface: RelNode
Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.eigenbase.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.

Specified by:
computeSelfCost in interface RelNode
computeSelfCost in class AbstractRelNode


public RelDataType deriveRowType()
deriveRowType in class SingleRel


public void explain(RelOptPlanWriter pw)
Specified by:
explain in interface RelNode
explain in class SingleRel


public FemExecutionStreamDef toStreamDef(FennelRelImplementor implementor)
Description copied from interface: FennelRel
Converts this relational expression to FemExecutionStreamDef form. In the process, the relational expression will almost certainly call FennelRelImplementor.visitFennelChild(net.sf.farrago.query.FennelRel, int) on each of its children.

implementor - for generating Java code
generated FemExecutionStreamDef