be.SIRAPRISE.server

Class __EXPRESSIONINFO_STRING_NAME

java.lang.Object

be.SIRAPRISE.server.__EXPRESSIONINFO_STRING_NAME

public final class __EXPRESSIONINFO_STRING_NAME
extends java.lang.Object

The operator implementation to get "introspective" ("meta") information on a given expression, and a given lexical scope designated by a single relvar name that can be passed.

Author:

Erwin Smout

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
ValueBuffer	executeOperator(java.util.LinkedList<ValueBuffer> args) Performs the actual logic of the operator.
ValueBuffer	executeOperator(java.util.LinkedList<ValueBuffer> args, be.SIRAPRISE.server.Luw luw) Performs the actual logic of the operator.
java.lang.String[]	getArgumentTypeNames() Gets the list of names of types of the needed argument values
static __EXPRESSIONINFO_STRING_NAME	getInstance() Gets instance
java.util.LinkedList<KeyDef>	getKeySpecificationsForRelationType() Gets the key specifications of the relation that will be output
java.lang.String	getPredicateForRelationType() Gets the predicate according to which the output relation is to be interpreted
TypeDeclaration	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)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static final __EXPRESSIONINFO_STRING_NAME getInstance()

Gets instance

Returns:

instance.

executeOperator

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

Description copied from interface: OperatorImplementation_V0104

Performs the actual logic of the operator.

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.

executeOperator

public ValueBuffer executeOperator(java.util.LinkedList<ValueBuffer> args,
                                   be.SIRAPRISE.server.Luw luw)

Performs the actual logic of the operator.

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.

luw - the luw that allows access to database operations, should they be needed for execution of the operator

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

Returns:

The names of the argument types

getKeySpecificationsForRelationType

public java.util.LinkedList<KeyDef> getKeySpecificationsForRelationType()

Gets the key specifications of the relation that will be output

Returns:

the key specifications of the relation that will be output

getPredicateForRelationType

public java.lang.String getPredicateForRelationType()

Gets the predicate according to which the output relation is to be interpreted

Returns:

the predicate according to which the output relation is to be interpreted

getReturnTypeName

public java.lang.String getReturnTypeName()

Description copied from interface: OperatorImplementation_V0104

Gets the name of the type of the return value

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

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().

Returns:

true if the operator is deterministic.

readExternal

public void readExternal(java.io.ObjectInput in)

writeExternal

public void writeExternal(java.io.ObjectOutput out)

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.

Returns:

the full type declaration of the type of the return value