saffron.rel.convert
Class Converter

java.lang.Object
  |
  +--saffron.rel.Rel
        |
        +--saffron.rel.SingleRel
              |
              +--saffron.rel.convert.Converter

Direct Known Subclasses:

AbstractConverter, ArrayConverter, CollectionConverter, EnumerationConverter, ExistsConverter, IterableConverter, IterConverter, JavaConverter, NoneConverter, PlanConverter, ResultSetConverter, VectorConverter

public abstract class Converter

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.

Nested Class Summary

Nested classes inherited from class saffron.rel.Rel

Field Summary

protected CallingConvention

inConvention

Fields inherited from class saffron.rel.SingleRel

child

Fields inherited from class saffron.rel.Rel

cluster, digest, id, rowType

Constructor Summary

protected

Converter(Cluster cluster, Rel child)

Method Summary

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

Methods inherited from class saffron.rel.SingleRel

childrenAccept, deriveRowType, explain, getInputs, replaceInput

Methods inherited from class saffron.rel.Rel

clone, computeDigest, getChildExps, getCluster, getConvention, getCorelVariable, getEnvironment, getId, getInput, getOrCreateCorelVariable, getParentEnv, getQualifier, getQuery, getRelTypeName, getRows, getRowType, getTable, getType, getVariablesStopped, implementExp, implementExps, implementFieldAccess, implementSelf, isAccessTo, isDistinct, onRegister, recomputeDigest, register, registerCorelVariable, setCorelVariable, 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

Converter

protected Converter(Cluster cluster,
                    Rel child)

Method Detail

computeSelfCost

public Cost computeSelfCost(Planner planner)

Description copied from class: Rel

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

Overrides:

computeSelfCost in class Rel

implement

public Object implement(Implementor implementor,
                        int ordinal)

Description copied from class: Rel

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

Overrides:

implement in class Rel

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.