org.eigenbase.rex
Class RexCall

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

Direct Known Subclasses:

FennelWindowRel.RexWinAggCall, RexOver

public class RexCall
extends RexNode

An expression formed by a call to an operator with zero or more expressions as operands.

Operators may be binary, unary, functions, special syntactic constructs like CASE ... WHEN ... END, or even internally generated constructs like implicit type conversions. The syntax of the operator is really irrelevant, because row-expressions (unlike SQL expressions) do not directly represent a piece of source code.

It's not often necessary to sub-class this class. The smarts should be in the operator, rather than the call. Any extra information about the call can often be encoded as extra arguments. (These don't need to be hidden, because no one is going to be generating source code from this tree.)

Since:

Nov 24, 2003

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rex/RexCall.java#23 $

Author:

jhyde

Field Summary

private RexKind	kind
private SqlOperator	op
RexNode[]	operands
private RelDataType	type

Fields inherited from class org.eigenbase.rex.RexNode

digest, EMPTY_ARRAY

Constructor Summary

protected

RexCall(RelDataType type, SqlOperator op, RexNode[] operands)

Method Summary

<R> R	accept(RexVisitor<R> visitor) Accepts a visitor, dispatching to the right overloaded visitXxx method.
RexCall	clone()
RexCall	clone(RelDataType type, RexNode[] operands) Creates a new call to the same operator with different operands.
protected String	computeDigest(boolean withType)
RexKind	getKind() Returns the kind of node this is.
RexNode[]	getOperands()
SqlOperator	getOperator()
RelDataType	getType()
(package private) static RexKind	sqlKindToRexKind(SqlKind kind) Returns the RexKind corresponding to a SqlKind.
String	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

op

private final SqlOperator op

operands

public final RexNode[] operands

type

private final RelDataType type

kind

private final RexKind kind

Constructor Detail

RexCall

protected RexCall(RelDataType type,
                  SqlOperator op,
                  RexNode[] operands)

Method Detail

sqlKindToRexKind

static RexKind sqlKindToRexKind(SqlKind kind)

Returns the RexKind corresponding to a SqlKind. Fails if there is none.

"Postcondition:"

return != null

computeDigest

protected String computeDigest(boolean withType)

toString

public String toString()

Overrides:

toString in class RexNode

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.

Specified by:

accept in class RexNode

getType

public RelDataType getType()

Specified by:

getType in class RexNode

clone

public RexCall clone()

Specified by:

clone in class RexNode

getKind

public RexKind getKind()

Description copied from class: RexNode

Returns the kind of node this is.

Overrides:

getKind in class RexNode

Returns:

A RexKind value, never null

getOperands

public RexNode[] getOperands()

getOperator

public SqlOperator getOperator()

clone

public RexCall clone(RelDataType type,
                     RexNode[] operands)

Creates a new call to the same operator with different operands.

Parameters:

type - Return type

operands - Operands to call

Returns:

New call