be.SIRAPRISE.typeimplementations

Class PROJECT_RELATION

java.lang.Object

be.SIRAPRISE.typeimplementations.PROJECT_RELATION

All Implemented Interfaces:

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

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

Author:

erwin

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
PROJECT_RELATION(Heading argumentHeading, java.util.Set<NameIdentifier> attributeNames) Creates the PROJECT_RELATION

Method Summary

Modifier and Type	Method and Description
static RelationBuffer	computeProjection(RelationBuffer relationBuffer, NameIdentifier... attributes)
ValueBuffer	executeOperator(java.util.LinkedList<ValueBuffer> args) Performs the actual logic of the operator.
java.lang.String[]	getArgumentTypeNames() Gets the list of names of types of the needed argument values
NonScalarTypeDeclaration	getReturnTypeDeclaration() Gets the full type declaration of the type of the return value.
java.lang.String	getReturnTypeName() Gets the name of the type of the return value
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)
static PROJECTInvocationResultDetails	validateExpressionDetails(Heading inputHeading, java.util.Set<NameIdentifier> attributeNames, java.lang.String inputPredicate, java.util.Collection<? extends KeyDef> inputKeySpecifications)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

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

Constructor Detail

PROJECT_RELATION

public PROJECT_RELATION(Heading argumentHeading,
                        java.util.Set<NameIdentifier> attributeNames)

Creates the PROJECT_RELATION

Parameters:

argumentHeading - the argument's heading

attributeNames - the set of attribute names to project the argument onto

Method Detail

executeOperator

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

Description copied from interface: OperatorImplementation_V0104

Performs the actual logic of the operator.

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()

Description copied from interface: OperatorImplementation_V0104

Gets the list of names of types of the needed argument values

Specified by:

getArgumentTypeNames in interface OperatorImplementation_V0104

Returns:

The names of the argument types

getReturnTypeDeclaration

public NonScalarTypeDeclaration 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()

Description copied from interface: OperatorImplementation_V0104

Gets the name of the type of the return value

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

computeProjection

public static RelationBuffer computeProjection(RelationBuffer relationBuffer,
                                               NameIdentifier... attributes)

Parameters:

relationBuffer - the buffer holding a relation subjected to a projection

attributes - the attributes to be retained in the result

Returns:

The result of projecting the given relation over the specified projection attributes

validateExpressionDetails

public static PROJECTInvocationResultDetails validateExpressionDetails(Heading inputHeading,
                                                                       java.util.Set<NameIdentifier> attributeNames,
                                                                       java.lang.String inputPredicate,
                                                                       java.util.Collection<? extends KeyDef> inputKeySpecifications)
                                                                throws NonExistingAttributeException

Parameters:

attributeNames - The set of projection attributes

inputHeading - The heading of a relational expression that is subjected to projection

inputPredicate - The predicate of which the relation subjected to the projection is the extension

inputKeySpecifications - The keys known to be satisfied by the relation that is subjected to this projection

Returns:

The technical details of the projection invocation

Throws:

NonExistingAttributeException - If an attribute is mentioned in the projection attribute list that does not appear in the heading