be.SIRAPRISE.typeimplementations

Class BinaryMinOperatorImplementation

java.lang.Object

be.SIRAPRISE.typeimplementations.BinaryMinOperatorImplementation

All Implemented Interfaces:

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

public final class BinaryMinOperatorImplementation
extends java.lang.Object
implements AggregationOperatorImplementation

The DATE 'maximumof' operator.

Author:

Erwin

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BinaryMinOperatorImplementation(OperatorImplementation_V0104 orderingOperatorImplementation, OperatorImplementation_V0104 maxValueOperatorImplementation) Creates the BinaryMinOperatorImplementation

Method Summary

Modifier and Type	Method and Description
ValueBuffer	executeOperator(java.util.LinkedList<ValueBuffer> args) MIN returns the lowest of the two values given
java.lang.String[]	getArgumentTypeNames() MIN takes two arguments, both of the same type, i.e.
ValueBuffer	getIdentityElement() The identity value is the value returned by LASTxxx(), where xxx is the type of the arguments, if such a LASTxxx() operator is implemented.
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

BinaryMinOperatorImplementation

public BinaryMinOperatorImplementation(OperatorImplementation_V0104 orderingOperatorImplementation,
                                       OperatorImplementation_V0104 maxValueOperatorImplementation)

Creates the BinaryMinOperatorImplementation

Parameters:

orderingOperatorImplementation - the implementation object for the comparison (GT()) operation underlying this MAX() operation.

maxValueOperatorImplementation - The implementation of the niladic LASTXXX() operator for the type of the arguments of the ordering operator, or null if there is no such operator

Method Detail

executeOperator

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

MIN returns the lowest of the two values given

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()

MIN takes two arguments, both of the same type, i.e. the arguments signature is the very same as that of the underlying GT operator.

Specified by:

getArgumentTypeNames in interface OperatorImplementation_V0104

Returns:

The names of the argument types

getIdentityElement

public ValueBuffer getIdentityElement()
                               throws NoIdentityElementException

The identity value is the value returned by LASTxxx(), where xxx is the type of the arguments, if such a LASTxxx() operator is implemented.

Specified by:

getIdentityElement in interface AggregationOperatorImplementation

Returns:

The identity element.

Throws:

NoIdentityElementException - if no LASTxxx() operator could be found for the argument type of this MIN operator, or if its evaluation resulted in some exception (in the latter case, this is recorded in the Logger.getLogger() logs configured for the JVM)

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