/*

  * Copyright 2005-2008 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.kew.engine.node;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Comparator;

 import java.util.Iterator;

 import java.util.List;

 import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;

 import org.kuali.rice.core.api.reflect.ObjectDefinition;

 import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;

 import org.kuali.rice.core.util.ClassLoaderUtils;

 import org.kuali.rice.kew.exception.ResourceUnavailableException;

 /**

  * A typesafe enumeration defining the various types of Nodes in the Workflow Engine.

  * This class was added to aid in unifying the node type concept across multiple

  * components within the system.  It also defines type hierarchys for the various

  * node types.

  *

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

  */

 public class NodeType {

     private static final String SIMPLE_NAME = "simple";

     private static final String JOIN_NAME = "join";

     private static final String SPLIT_NAME = "split";

     private static final String SUB_PROCESS_NAME = "process";

     private static final String DYNAMIC_NAME = "dynamic";

     private static final String START_NAME = "start";

     private static final String REQUEST_ACTIVATION_NAME = "requestActivation";

     private static final String REQUESTS_NAME = "requests";

     private static final String ROLE_NAME = "role";

     /**

      * A Sorted List containing the NodeTypes in order sorted by largest extension depth first, i.e. in bottom-up extension order.

      */

     private static final List typeList = new ArrayList();

     private static final Comparator depthComparator = new ExtensionDepthComparator();

     // primitive node types

     public static final NodeType SIMPLE = new NodeType(SIMPLE_NAME, SimpleNode.class, null);

     public static final NodeType SPLIT = new NodeType(SPLIT_NAME, SplitNode.class, SimpleSplitNode.class);

     public static final NodeType JOIN = new NodeType(JOIN_NAME, JoinNode.class, SimpleJoinNode.class);

     public static final NodeType SUB_PROCESS = new NodeType(SUB_PROCESS_NAME, SubProcessNode.class, SimpleSubProcessNode.class);

     public static final NodeType DYNAMIC = new NodeType(DYNAMIC_NAME, DynamicNode.class, null);

     // derivative node types

     public static final NodeType REQUEST_ACTIVATION = new NodeType(SIMPLE, REQUEST_ACTIVATION_NAME, RequestActivationNode.class, RequestActivationNode.class);

     public static final NodeType START = new NodeType(REQUEST_ACTIVATION, START_NAME, InitialNode.class, InitialNode.class);

     public static final NodeType REQUESTS = new NodeType(REQUEST_ACTIVATION, REQUESTS_NAME, RequestsNode.class, RequestsNode.class);

     public static final NodeType ROLE = new NodeType(REQUESTS, ROLE_NAME, RoleNode.class, RoleNode.class);

     private NodeType extensionBase;

     private String name;

     private Class baseClass;

     private Class defaultClass;

     private int extensionDepth = 0;

     private NodeType(String name, Class baseClass, Class defaultClass) {

         this(null, name, baseClass, defaultClass);

     }

     private NodeType(NodeType extensionBase, String name, Class baseClass, Class defaultClass) {

         this.extensionBase = extensionBase;

         this.name = name;

         this.baseClass = baseClass;

         this.defaultClass = defaultClass;

         while (extensionBase != null) {

             extensionDepth++;

             extensionBase = extensionBase.getExtensionBase();

         }

         typeList.add(this);

         // keep the list sorted

         Collections.sort(typeList, depthComparator);

     }

     public NodeType getExtensionBase() {

         return extensionBase;

     }

     public Class getBaseClass() {

         return baseClass;

     }

     public Class getDefaultClass() {

         return defaultClass;

     }

     public String getName() {

         return name;

     }

     public int getExtensionDepth() {

         return extensionDepth;

     }

     public boolean isAssignableFrom(Class typeClass) {

         return getBaseClass().isAssignableFrom(typeClass);

     }

     public boolean isAssignableFrom(NodeType type) {

         return getBaseClass().isAssignableFrom(type.getBaseClass());

     }

     public boolean isInstanceOf(Object object) {

             return ClassLoaderUtils.isInstanceOf(object, getBaseClass());

     }

     public boolean isTypeOf(Class typeClass) {

         return typeClass.isAssignableFrom(getBaseClass());

     }

     public boolean isTypeOf(NodeType type) {

         return type.getBaseClass().isAssignableFrom(getBaseClass());

     }

     public boolean isCustomNode(String className) {

         return getDefaultClass() == null || !getDefaultClass().getName().equals(className);

     }

     public boolean equals(Object object) {

         if (object instanceof NodeType) {

             return ((NodeType)object).name.equals(name);

         }

         return false;

     }

     public int hashCode() {

         return name.hashCode();

     }

     public static NodeType fromClassName(String className) throws ResourceUnavailableException {

         //Class typeClass = SpringServiceLocator.getExtensionService().loadClass(className);

         Object typeObject = GlobalResourceLoader.getResourceLoader().getObject(new ObjectDefinition(className));

         if (typeObject == null) {

                 throw new ResourceUnavailableException("Could not locate the node with the given class name '" + className + "'.");

         }

         //Class typeClass = typeObject.getClass();

             // depends upon the proper sorting of typeList

         for (Iterator iterator = typeList.iterator(); iterator.hasNext();) {

             NodeType type = (NodeType) iterator.next();

             //if (type.isAssignableFrom(typeClass)) {

             //if (ClassLoaderUtils.isInstanceOf(typeObject, type))

             if (type.isInstanceOf(typeObject)) {

                 return type;

             }

         }

         return null;

     }

     public static NodeType fromNode(RouteNode node) throws ResourceUnavailableException {

         return fromClassName(node.getNodeType());

     }

     public static NodeType fromNodeInstance(RouteNodeInstance nodeInstance) throws ResourceUnavailableException {

         return fromNode(nodeInstance.getRouteNode());

     }

     /**

      * Sorts in descending extension-depth order.

      */

     private static class ExtensionDepthComparator implements Comparator {

         public int compare(Object object1, Object object2) {

             NodeType type1 = (NodeType)object1;

             NodeType type2 = (NodeType)object2;

             if (type1.getExtensionDepth() > type2.getExtensionDepth()) {

                 return -1;

             } else if (type1.getExtensionDepth() < type2.getExtensionDepth()) {

                 return 1;

             }

             return 0;

         }

     }

     public static List<NodeType> getTypeList(){

             return typeList;

     }

 }