org.eigenbase.rex
Class RexOver

java.lang.Object
  org.eigenbase.rex.RexNode
      org.eigenbase.rex.RexCall
          org.eigenbase.rex.RexOver

public class RexOver
extends RexCall

Call to an aggregate function over a window.

Since:

Dec 6, 2004

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rex/RexOver.java#16 $

Author:

jhyde

Nested Class Summary

private static class	RexOver.Finder Visitor which detects a RexOver inside a RexNode expression.
private static class	RexOver.OverFound

Field Summary

private RexWindow

window

Fields inherited from class org.eigenbase.rex.RexCall

operands

Fields inherited from class org.eigenbase.rex.RexNode

digest, EMPTY_ARRAY

Constructor Summary

RexOver(RelDataType type, SqlAggFunction op, RexNode[] operands, RexWindow window)
Creates a RexOver.

Method Summary

<R> R	accept(RexVisitor<R> visitor) Accepts a visitor, dispatching to the right overloaded visitXxx method.
RexOver	clone()
protected String	computeDigest(boolean withType)
static boolean	containsOver(RexNode expr) Returns whether an expression contains an OVER clause.
static boolean	containsOver(RexNode[] exprs, RexNode expr) Deprecated.
static boolean	containsOver(RexProgram program) Returns whether a program contains an OVER clause.
SqlAggFunction	getAggOperator() Returns the aggregate operator for this expression.
RexWindow	getWindow()

Methods inherited from class org.eigenbase.rex.RexCall

clone, getKind, getOperands, getOperator, getType, sqlKindToRexKind, toString

Methods inherited from class org.eigenbase.rex.RexNode

isA, isAlwaysTrue

Methods inherited from class java.lang.Object

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

Field Detail

window

private final RexWindow window

Constructor Detail

RexOver

RexOver(RelDataType type,
        SqlAggFunction op,
        RexNode[] operands,
        RexWindow window)

Creates a RexOver.

For example, "SUM(x) OVER (ROWS 3 PRECEDING)" is represented as:

• type = Integer,
• op = SqlStdOperatorTable.sumOperator,
• operands = { RexFieldAccess("x") }
• window = SqlWindow(ROWS 3 PRECEDING)

Parameters:

type - Result type

op - Aggregate operator

operands - Operands list

window - Window specification

"Precondition:"

op.isAggregator(), window != null, window.getRefName() == null

Method Detail

getAggOperator

public SqlAggFunction getAggOperator()

Returns the aggregate operator for this expression.

getWindow

public RexWindow getWindow()

computeDigest

protected String computeDigest(boolean withType)

Overrides:

computeDigest in class RexCall

clone

public RexOver clone()

Overrides:

clone in class RexCall

accept

public <R> R accept(RexVisitor<R> visitor)

Description copied from class: RexNode

Accepts a visitor, dispatching to the right overloaded visitXxx method.

Also see RexProgram.apply(RexVisitor, RexNode[], RexNode), which applies a visitor to several expressions simultaneously.

Overrides:

accept in class RexCall

containsOver

public static boolean containsOver(RexNode expr)

Returns whether an expression contains an OVER clause.

containsOver

public static boolean containsOver(RexProgram program)

Returns whether a program contains an OVER clause.

containsOver

public static boolean containsOver(RexNode[] exprs,
                                   RexNode expr)

Deprecated.

Returns whether an expression list contains an OVER clause.