be.SIRAPRISE.typeimplementations

Class ChooseOperatorImplementation

java.lang.Object

be.SIRAPRISE.typeimplementations.ChooseOperatorImplementation

All Implemented Interfaces:

OperatorImplementation_V0104, OperatorImplementation_V0105, java.io.Externalizable, java.io.Serializable

public final class ChooseOperatorImplementation
extends java.lang.Object
implements OperatorImplementation_V0105

The CHOOSE operator implementation.

Author:

Erwin

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ChooseOperatorImplementation(java.lang.String chooseForTypeName) Creates the ChooseOperatorImplementation

Method Summary

Modifier and Type	Method and Description
ValueBuffer	executeOperator(java.util.LinkedList<ValueBuffer> args) CHOOSE returns the 2nd or 3d argument, depending on the truth value of the first
java.lang.String[]	getArgumentTypeNames() CHOOSE takes three arguments, the first of type BOOLEAN, the other two of the same type, which is also the return type
TypeDeclaration	getReturnTypeDeclaration() Gets the full type declaration of the type of the return value.
java.lang.String	getReturnTypeName() The return type is the same as the arguments' type
java.lang.String	getSignature() Gets the name of the operator implemented by this implementation object
boolean	isDeterministic() Tells whether the operator is deterministic with respect to the arguments of its invocations.
void	readExternal(java.io.ObjectInput in)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ChooseOperatorImplementation

public ChooseOperatorImplementation(java.lang.String chooseForTypeName)

Creates the ChooseOperatorImplementation

Parameters:

chooseForTypeName - The name of the (scalar !!!) type for which a CHOOSE operator implementation is to be created. CHOOSE for nonscalar types is not yet supported.

Method Detail

executeOperator

public ValueBuffer executeOperator(java.util.LinkedList<ValueBuffer> args)

CHOOSE returns the 2nd or 3d argument, depending on the truth value of the first

Specified by:

executeOperator in interface OperatorImplementation_V0104

Parameters:

args - the argument list. The list must hold as many ValueBuffer objects as there are arguments to the operator, and each ValueBuffer object holds a value for some argument to the operator. ValueBuffer objects on the list must appear in the same order as the operator argument declarations. Implementations have the option, but are not required, to do a check the conformance of the argument list (the argument count, notably) to the operator signature.

Returns:

A ValueBuffer object holding the result value of the operator execution in internal format.

getArgumentTypeNames

public java.lang.String[] getArgumentTypeNames()

CHOOSE takes three arguments, the first of type BOOLEAN, the other two of the same type, which is also the return type

Specified by:

getArgumentTypeNames in interface OperatorImplementation_V0104

Returns:

The names of the argument types

getReturnTypeDeclaration

public TypeDeclaration getReturnTypeDeclaration()

Description copied from interface: OperatorImplementation_V0105

Gets the full type declaration of the type of the return value. Differs from the _V0104 getReturnTypeName() in that for nonscalar return types, this method also returns the heading, not just only the RELATION or TUPLE typename.

Specified by:

getReturnTypeDeclaration in interface OperatorImplementation_V0105

Returns:

the full type declaration of the type of the return value

getReturnTypeName

public java.lang.String getReturnTypeName()

The return type is the same as the arguments' type

Specified by:

getReturnTypeName in interface OperatorImplementation_V0104

Returns:

the name of the type of the return value

getSignature

public java.lang.String getSignature()

Description copied from interface: OperatorImplementation_V0104

Gets the name of the operator implemented by this implementation object

Specified by:

getSignature in interface OperatorImplementation_V0104

Returns:

the name of the operator implemented by this implementation object

isDeterministic

public boolean isDeterministic()

Description copied from interface: OperatorImplementation_V0104

Tells whether the operator is deterministic with respect to the arguments of its invocations. An operator is deterministic if and only if for any two distinct invocations, if all the argument values are the same, then the result value returned will also be the same. An example of a nondeterministic operators is RANDOM().

Specified by:

isDeterministic in interface OperatorImplementation_V0104

Returns:

true if the operator is deterministic.

readExternal

public void readExternal(java.io.ObjectInput in)

Specified by:

readExternal in interface java.io.Externalizable

writeExternal

public void writeExternal(java.io.ObjectOutput out)

Specified by:

writeExternal in interface java.io.Externalizable