net.sf.saffron.oj.rel
Class JavaProjectRel

java.lang.Object
  |
  +--net.sf.saffron.rel.SaffronRel
        |
        +--net.sf.saffron.rel.SingleRel
              |
              +--net.sf.saffron.rel.ProjectRelBase
                    |
                    +--net.sf.saffron.rel.ProjectRel
                          |
                          +--net.sf.saffron.oj.rel.JavaProjectRel

All Implemented Interfaces:

JavaRel

public class JavaProjectRel

extends ProjectRel

implements JavaRel

Implements the ProjectRel relational expression as Java code.

Nested Class Summary

Nested classes inherited from class net.sf.saffron.rel.ProjectRelBase

ProjectRelBase.Flags

Field Summary

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

exps, fieldNames, flags

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

JavaProjectRel(VolcanoCluster cluster, SaffronRel child, RexNode[] exps, String[] fieldNames, int flags)

Method Summary

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

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

computeSelfCost, defineTerms, deriveRowType, explain, getChildExps, getFieldNames, getFlags, implementFieldAccess, isBoxed

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

childrenAccept, getInputs, getRows, replaceInput

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaProjectRel

public JavaProjectRel(VolcanoCluster cluster,
                      SaffronRel child,
                      RexNode[] exps,
                      String[] fieldNames,
                      int flags)

Method Detail

getConvention

public CallingConvention getConvention()

Description copied from class: SaffronRel

Returns a value from CallingConvention.

Overrides:

getConvention in class SaffronRel

clone

public Object clone()

Overrides:

clone in class ProjectRel

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.

implementSelf

public Expression implementSelf(RelImplementor 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, ...);
  {parent-handler(v)}
  

If the row-type is simple, generate

  V v = exp;
  {parent-handler(v)}
  

Todo: map relations to expressions (not variables), so we don't have to create new objects:

  T1 v1 = exp1;
  T2 v2 = exp2;
  {parent-handler(v1,v2)}
  

Or at least, create a holder object outside the loop, and just assign into it:

  V v = new V();
  {loop} {
  v.v1 = exp1;
  v.v2 = exp2;
  {parent-handler(v)}
  }
  

Specified by:

implementSelf in interface JavaRel

See Also:

RelImplementor.bind(SaffronRel,SaffronRel)