org.apache.calcite.rex

Class RexNode

java.lang.Object

org.apache.calcite.rex.RexNode

Direct Known Subclasses:

RexCall, RexFieldAccess, RexLiteral, RexRangeRef, RexVariable

public abstract class RexNode
extends Object

Row expression.

Every row-expression has a type. (Compare with SqlNode, which is created before validation, and therefore types may not be available.)

Some common row-expressions are: RexLiteral (constant value), RexVariable (variable), RexCall (call to operator with operands). Expressions are generally created using a RexBuilder factory.

All sub-classes of RexNode are immutable.

Field Summary

Fields

Modifier and Type	Field and Description
protected @MonotonicNonNull String	digest

Constructor Summary

Constructors

Constructor and Description
RexNode()

Method Summary

Modifier and Type	Method and Description
abstract <R,P> R	accept(RexBiVisitor<R,P> visitor, P arg) Accepts a visitor with a payload, dispatching to the right overloaded RexBiVisitor.visitInputRef(RexInputRef, Object) visitXxx} method.
abstract <R> R	accept(RexVisitor<R> visitor) Accepts a visitor, dispatching to the right overloaded visitXxx method.
abstract boolean	equals(@Nullable Object obj)
SqlKind	getKind() Returns the kind of node this is.
abstract RelDataType	getType()
abstract int	hashCode()
boolean	isA(Collection<SqlKind> kinds)
boolean	isA(SqlKind kind)
boolean	isAlwaysFalse() Returns whether this expression always returns false.
boolean	isAlwaysTrue() Returns whether this expression always returns true.
int	nodeCount() Returns the number of nodes in this expression.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

digest

protected @MonotonicNonNull String digest

Constructor Detail

RexNode

public RexNode()

Method Detail

getType

public abstract RelDataType getType()

isAlwaysTrue

public boolean isAlwaysTrue()

Returns whether this expression always returns true. (Such as if this expression is equal to the literal TRUE.)

isAlwaysFalse

public boolean isAlwaysFalse()

Returns whether this expression always returns false. (Such as if this expression is equal to the literal FALSE.)

isA

public boolean isA(SqlKind kind)

isA

public boolean isA(Collection<SqlKind> kinds)

getKind

public SqlKind getKind()

Returns the kind of node this is.

Returns:

Node kind, never null

toString

public String toString()

Overrides:

toString in class Object

nodeCount

public int nodeCount()

Returns the number of nodes in this expression.

Leaf nodes, such as RexInputRef or RexLiteral, have a count of 1. Calls have a count of 1 plus the sum of their operands.

Node count is a measure of expression complexity that is used by some planner rules to prevent deeply nested expressions.

accept

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

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

Also see RexUtil.apply(RexVisitor, java.util.List, RexNode), which applies a visitor to several expressions simultaneously.

accept

public abstract <R,P> R accept(RexBiVisitor<R,P> visitor,
                               P arg)

Accepts a visitor with a payload, dispatching to the right overloaded RexBiVisitor.visitInputRef(RexInputRef, Object) visitXxx} method.

equals

public abstract boolean equals(@Nullable Object obj)

Every node must implement equals(java.lang.Object) based on its content

Overrides:

equals in class Object

hashCode

public abstract int hashCode()

Every node must implement hashCode() consistent with equals(java.lang.Object)

Overrides:

hashCode in class Object