Class LogicalOpMultiRequest

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.logical.impl.BaseForLogicalOps

se.liu.ida.hefquin.engine.queryplan.logical.impl.LogicalOpMultiRequest

All Implemented Interfaces:

QueryPlanOperator, LogicalOperator, NullaryLogicalOp

public class LogicalOpMultiRequest
extends BaseForLogicalOps
implements NullaryLogicalOp

This operator has three arguments: i) a SPARQL graph pattern P (given in the form of a SPARQLRequest, ii) a variable ?v, and iii) a set of federation members. The evaluation semantics is equivalent to the one of the following SPARQL query, assuming that the URIs in the VALUES clause are the service URIs of the given federation members.

 SELECT * WHERE {
    VALUES ?v { ex:serviceURI_1 ex:serviceURI_2 ... ex:serviceURI_n }
    SERVICE ?v {
       # pattern P
    }
 }
 

Notice that every solution mapping in the result of this operator will bind the given variable ?v to the service URI of the federation member from which the rest of this solution mapping has been received.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Set<FederationMember>	fms
protected final SPARQLRequest	req
protected final org.apache.jena.sparql.core.Var	var

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.logical.impl.BaseForLogicalOps

mayReduce

Constructor Summary

Constructors

Constructor	Description
LogicalOpMultiRequest(SPARQLRequest req, org.apache.jena.sparql.core.Var var, Set<FederationMember> fms)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
ExpectedVariables	getExpectedVariables(ExpectedVariables... inputVars)	Returns the variables that can be expected in the solution mappings produced by this operator in the case that the input(s) to this operator contain solutions mappings with the given set(s) of variables.
Set<FederationMember>	getFederationMembers()
SPARQLRequest	getRequest()
org.apache.jena.sparql.core.Var	getServiceVariable()
int	hashCode()
String	toString()
void	visit(LogicalPlanVisitor visitor)

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.logical.impl.BaseForLogicalOps

mayReduce

Methods inherited from class java.lang.Object

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

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.logical.LogicalOperator

mayReduce

Field Details

req

protected final SPARQLRequest req

var

protected final org.apache.jena.sparql.core.Var var

fms

protected final Set<FederationMember> fms

Constructor Details

LogicalOpMultiRequest

public LogicalOpMultiRequest(SPARQLRequest req,
 org.apache.jena.sparql.core.Var var,
 Set<FederationMember> fms)

Method Details

getRequest

public SPARQLRequest getRequest()

getServiceVariable

public org.apache.jena.sparql.core.Var getServiceVariable()

getFederationMembers

public Set<FederationMember> getFederationMembers()

getExpectedVariables

public ExpectedVariables getExpectedVariables(ExpectedVariables... inputVars)

Description copied from interface: QueryPlanOperator

Returns the variables that can be expected in the solution mappings produced by this operator in the case that the input(s) to this operator contain solutions mappings with the given set(s) of variables. The number of ExpectedVariables objects passed to this method must be in line with the degree of this operator (e.g., for a unary operator, exactly one such object must be passed).

Specified by:

getExpectedVariables in interface QueryPlanOperator

visit

public void visit(LogicalPlanVisitor visitor)

Specified by:

visit in interface LogicalOperator

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object