package org.kuali.rice.krms.framework.engine;

 import java.util.Map;

 import org.kuali.rice.krms.api.engine.ExecutionOptions;

 import org.kuali.rice.krms.api.engine.SelectionCriteria;

 import org.kuali.rice.krms.api.engine.Term;

 /**

  * Loads a {@link Context} for the given set of criteria.  Applications who

  * want to provide their own means for creating a context and supplying it to

  * the KRMS engine can do so by implementing a custom ContextProvider. 

  * 

  * @see Context

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public interface ContextProvider {

         /**

          * Loads the context for the given selection criteria, facts, and execution

          * options.  If no context can be located based on the given criteria, then

          * this method should return null.

          * 

          * <p>In the case where multiple Contexts could potentially be identified

          * from the same set of selection criteria, it is up to the implementer

          * of the ContextProvider to ensure that the most appropriate Context is

          * returned.  Or alternatively, an exception could be thrown indicating

          * context ambiguity.

          * 

          * <p>The sectionCriteria, facts, and executionOptions which are passed to

          * this method should never be null.  However, they might be empty.

          * 

          * @param selectionCriteria the criteria to use during the selection phase of engine operation

          * @param facts the set of facts that are supplied to the engine at execution time

          * @param executionOptions a collection of options that can be used to customize engine execution behavior

          * 

          * @return the context which matches the given criteria, or null if no context matches

          */

         public Context loadContext(SelectionCriteria selectionCriteria, Map<Term, Object> facts, ExecutionOptions executionOptions);

 }