/**

Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016.  All rights reserved.

Contact:
     SYSTAP, LLC DBA Blazegraph
     2501 Calvert ST NW #106
     Washington, DC 20008
     licenses@blazegraph.com

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
 * Created on Sep 8, 2011
 */

package com.bigdata.rdf.sparql.ast.service;

import java.util.Set;

import com.bigdata.bop.IVariable;
import com.bigdata.rdf.sparql.ast.IVariableBindingRequirements;
import com.bigdata.rdf.sparql.ast.StaticAnalysis;


/**
 * Factory for creating objects which can talk to SPARQL service end points.
 */
public interface ServiceFactory {

    /**
     * Return options for the service end point. Depending on the
     * implementation, these options MAY be configurable.
     */
    IServiceOptions getServiceOptions();
    
    /**
     * Create a service invocation object.
     * 
     * @param params
     *            The pararameters, which are encapsulated by this interface.
     * 
     * @return The object which can be used to evaluate the SERVICE clause.
     */
    ServiceCall<?> create(ServiceCallCreateParams params);

    /**
     * Returns, for the given service node, the variables that must be
     * bound prior to start executing the service. This information is 
     * important to reason about the position where to place the service
     * within the execution proccess.
     * 
     * See 
     * {@link IVariableBindingRequirements#getRequiredBound(StaticAnalysis)}.
     */
    public Set<IVariable<?>> getRequiredBound(final ServiceNode serviceNode);

    /**
     * Returns, for the given service node, the variables that are desired
     * to be bound prior to start executing the service. This information is 
     * important to reason about the position where to place the service
     * within the execution proccess.
     * 
     * See 
     * {@link IVariableBindingRequirements#getDesiredBound(StaticAnalysis)}.
     */
    public Set<IVariable<?>> getDesiredBound(final ServiceNode serviceNode);    
    
}