/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.krms.api.repository.function;

 import org.kuali.rice.core.api.mo.common.Identifiable;

 import org.kuali.rice.core.api.mo.common.Versioned;

 import org.kuali.rice.core.api.mo.common.active.Inactivatable;

 import org.kuali.rice.krms.api.repository.category.CategoryDefinitionContract;

 import org.kuali.rice.krms.api.repository.type.KrmsTypeDefinition;

 import java.util.List;

 /**

  * Defines the contract for a function definition.  A function definition can be

  * defined by clients integrating with KRMS in order to implement custom logic

  * which they may require as part of rule execution and evaluation.  These can

  * then be used in simple propositions.

  * 

  * <p>The function definition itself defines various metadata about the function

  * including it's name, return type, and expected parameter types.  The actual

  * implementation of the function is retrieved through the type defined by

  * {@link #getTypeId()}.

  * 

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

  *

  */

 public interface FunctionDefinitionContract extends Versioned, Identifiable, Inactivatable {

         /**

          * Returns the namespace code of this function definition.  All functions

          * have a namespace and this value can never be null or blank.  The

          * combination of namespace plus name must be unique within the entire

          * repository of functions.

          * 

          * @return the namespace code of this function definition

          */

         String getNamespace();

         /**

          * Returns the name of this function definition.  All functions have a name

          * and this value can never be null or blank.  The combination of namespace

          * plus name must be unique within the entire repository of functions.

          * 

          * @return the name of this function definition

          */

         String getName();

         /**

          * Returns the description of this function definition.  The description is

          * intended to provide more information about a function and it's

          * appropriate usage.  The description is optional.

          * 

          * @return the description of this function definition

          */

         String getDescription();

         /**

          * Returns the type of the return value of the function defined by this

          * function definition.  This can be one of a set of "built-in" data types

          * or a custom data type represented as a fully qualified java class name.

          * All functions must have a return type so this method should never return

          * null or blank.

          * 

          * @return the return type of this function definition

          */

         String getReturnType();

         /**

          * Returns the id of the {@link KrmsTypeDefinition} which defines the

          * actual implementation of this function such that it can be loaded into

          * the engine and executed.

          * 

          * @return the type id of this function definition

          */

         String getTypeId();

         /**

          * Returns an ordered, immutable list of the parameters which this function

          * definition requires.  This list can be empty (in the case of a function

          * which has no arguments) but will never be null.

          * 

          * @return the list of parameters for this function definition

          */

         List<? extends FunctionParameterDefinitionContract> getParameters();

     /**

      * Returns an ordered list of the categories which this function

      * definition requires.  This list can be empty (in the case of a function

      * which has no arguments) but will never be null.

      *

      * @return the list of categories for this function definition

      */

     List<? extends CategoryDefinitionContract> getCategories();

 }