saffron.rel.java
Class JavaProject

java.lang.Object
  |
  +--saffron.rel.Rel
        |
        +--saffron.rel.SingleRel
              |
              +--saffron.rel.Project
                    |
                    +--saffron.rel.java.JavaProject

public class JavaProject

extends Project

JavaProject implements the Project relational expression as Java code.

Nested Class Summary

Nested classes inherited from class saffron.rel.Project

Project.Flags

Nested classes inherited from class saffron.rel.Rel

Field Summary

Fields inherited from class saffron.rel.Project

exps, fieldNames, flags

Fields inherited from class saffron.rel.SingleRel

child

Fields inherited from class saffron.rel.Rel

cluster, digest, id, rowType

Constructor Summary

JavaProject(Cluster cluster, Rel child, Expression[] exps, String[] fieldNames, int flags)

Method Summary

Object	clone()
CallingConvention	getConvention() Returns a value from CallingConvention.
Object	implement(Implementor implementor, int ordinal) Create a plan for this expression according to a calling convention.
Expression	implementSelf(Implementor implementor) Generates the initializer for the variable which holds the current row of this project.

Methods inherited from class saffron.rel.Project

computeSelfCost, deriveRowType, explain, getChildExps, getFlags, implementFieldAccess, isBoxed, register

Methods inherited from class saffron.rel.SingleRel

childrenAccept, getInputs, replaceInput

Methods inherited from class saffron.rel.Rel

computeDigest, getCluster, getCorelVariable, getEnvironment, getId, getInput, getOrCreateCorelVariable, getParentEnv, getQualifier, getQuery, getRelTypeName, getRows, getRowType, getTable, getType, getVariablesStopped, implementExp, implementExps, isAccessTo, isDistinct, onRegister, recomputeDigest, registerCorelVariable, setCorelVariable, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaProject

public JavaProject(Cluster cluster,
                   Rel child,
                   Expression[] exps,
                   String[] fieldNames,
                   int flags)

Method Detail

clone

public Object clone()

Overrides:

clone in class Project

getConvention

public CallingConvention getConvention()

Description copied from class: Rel

Returns a value from CallingConvention.

Overrides:

getConvention 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.

implementSelf

public Expression implementSelf(Implementor implementor)

Generates the initializer for the variable which holds the current row of this project. If the row-type V is complex, generate V v = new V(exp, ...); <> If the row-type is simple, generate V v = exp; <> Todo: map relations to expressions (not variables), so we don't have to create new objects: T1 v1 = exp1; T2 v2 = exp2; <> Or at least, create a holder object outside the loop, and just assign into it: V v = new V(); <> { v.v1 = exp1; v.v2 = exp2; <> }

Overrides:

implementSelf in class Rel

See Also:

Implementor#bind(Rel,Rel)