net.sf.saffron.rel.convert
Class ConverterRel

java.lang.Object
  |
  +--net.sf.saffron.rel.SaffronRel
        |
        +--net.sf.saffron.rel.SingleRel
              |
              +--net.sf.saffron.rel.convert.ConverterRel

Direct Known Subclasses:

AbstractConverter, ArrayConverterRel, CollectionConverterRel, EnumerationConverterRel, ExistsConverterRel, IterableConverterRel, IterConverterRel, JavaConverterRel, NoneConverterRel, ResultSetConverterRel, VectorConverterRel

public abstract class ConverterRel

extends SingleRel

Converts a relational expression from one calling convention to another.

Sometimes this conversion is expensive; for example, to convert a non-distinct to a distinct object stream, we have to clone every object in the input.

Field Summary

protected CallingConvention

inConvention

Fields inherited from class net.sf.saffron.rel.SingleRel

child

Fields inherited from class net.sf.saffron.rel.SaffronRel

cluster, digest, id, rowType

Constructor Summary

protected

ConverterRel(VolcanoCluster cluster, SaffronRel child)

Method Summary

PlanCost	computeSelfCost(SaffronPlanner planner) Returns the cost of this plan (not including children).
Object	implement(RelImplementor implementor, int ordinal) Create a plan for this expression according to a calling convention.

Methods inherited from class net.sf.saffron.rel.SingleRel

childrenAccept, deriveRowType, explain, getInputs, getRows, replaceInput

Methods inherited from class net.sf.saffron.rel.SaffronRel

clone, computeDigest, getChildExps, getCluster, getConvention, getCorrelVariable, getId, getInput, getOrCreateCorrelVariable, getQualifier, getQuery, getRelTypeName, getRowType, getTable, getVariablesStopped, implementFieldAccess, isAccessTo, isDistinct, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

inConvention

protected CallingConvention inConvention

Constructor Detail

ConverterRel

protected ConverterRel(VolcanoCluster cluster,
                       SaffronRel child)

Method Detail

computeSelfCost

public PlanCost computeSelfCost(SaffronPlanner planner)

Description copied from class: SaffronRel

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

Overrides:

computeSelfCost in class SaffronRel

implement

public Object implement(RelImplementor implementor,
                        int ordinal)

Description copied from class: SaffronRel

Create a plan for this expression according to a calling convention.

Overrides:

implement in class SaffronRel

Parameters:

implementor - implementor

ordinal - indicates our position in the pre-, in- and postfix walk over the tree; ordinal is -1 when called from the parent, and i when called from the i^th child.