org.eigenbase.rel
Class FilterRel

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel
          org.eigenbase.rel.FilterRelBase
              org.eigenbase.rel.FilterRel

All Implemented Interfaces:

Cloneable, RelNode

public final class FilterRel
extends FilterRelBase

A FilterRel is a relational expression which iterates over its input, and returns elements for which condition evaluates to true.

Field Summary

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

FilterRel(RelOptCluster cluster, RelNode child, RexNode condition)
Creates a filter.

Method Summary

FilterRel

clone() Clones this RelNode.

Methods inherited from class org.eigenbase.rel.FilterRelBase

computeSelfCost, estimateFilteredRows, estimateFilteredRows, explain, getChildExps, getCondition, getRows

Methods inherited from class org.eigenbase.rel.SingleRel

childrenAccept, deriveRowType, getChild, getInputs, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, isValid, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

FilterRel

public FilterRel(RelOptCluster cluster,
                 RelNode child,
                 RexNode condition)

Creates a filter.

Parameters:

cluster - RelOptCluster this relational expression belongs to

child - input relational expression

condition - boolean expression which determines whether a row is allowed to pass

Method Detail

clone

public FilterRel 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(...);
         clone.inheritTraitsFrom(this);
         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

Returns:

a clone of this RelNode