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1   /*
2    * *************************************************************************************************************************************************************
3    *
4    * TheseFoolishThings: Miscellaneous utilities
5    * http://tidalwave.it/projects/thesefoolishthings
6    *
7    * Copyright (C) 2009 - 2025 by Tidalwave s.a.s. (http://tidalwave.it)
8    *
9    * *************************************************************************************************************************************************************
10   *
11   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12   * You may obtain a copy of the License at
13   *
14   *     http://www.apache.org/licenses/LICENSE-2.0
15   *
16   * 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
17   * CONDITIONS OF ANY KIND, either express or implied.  See the License for the specific language governing permissions and limitations under the License.
18   *
19   * *************************************************************************************************************************************************************
20   *
21   * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22   * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23   *
24   * *************************************************************************************************************************************************************
25   */
26  package it.tidalwave.actor.spi;
27  
28  import java.lang.reflect.InvocationTargetException;
29  import javax.annotation.Nonnegative;
30  import jakarta.annotation.Nonnull;
31  import it.tidalwave.actor.annotation.Actor;
32  import it.tidalwave.actor.impl.CollaborationAwareMessageBusAdapter;
33  import it.tidalwave.actor.impl.ExecutorWithPriority;
34  import it.tidalwave.actor.impl.MBeansManager;
35  import it.tidalwave.actor.impl.PostConstructInvoker;
36  import it.tidalwave.actor.impl.PreDestroyInvoker;
37  import lombok.Getter;
38  import lombok.extern.slf4j.Slf4j;
39  import static it.tidalwave.messagebus.spi.ReflectionUtils.*;
40  
41  /***************************************************************************************************************************************************************
42   *
43   * This class is used to activate and deactivate an actor.
44   *
45   * @author  Fabrizio Giudici
46   *
47   **************************************************************************************************************************************************************/
48  @Slf4j
49  public class ActorActivator
50    {
51      @Nonnull
52      private final Class<?> actorClass;
53  
54      @Nonnegative @Getter
55      private final int poolSize;
56  
57      @Getter
58      private Object actorObject;
59  
60      private ExecutorWithPriority executor;
61  
62      private CollaborationAwareMessageBusAdapter messageBusAdapter;
63  
64      private MBeansManager mBeansManager;
65  
66      /***********************************************************************************************************************************************************
67       * Creates an instance for the given actor class.
68       *
69       * @param  actorClass   the actor class
70       * @return              the instance
71       **********************************************************************************************************************************************************/
72      public static ActorActivator activatorFor (@Nonnull final Class<?> actorClass)
73        {
74          return new ActorActivator(actorClass, 1);
75        }
76  
77      /***********************************************************************************************************************************************************
78       * Specifies the pool size for this activator.
79       *
80       * @param  poolSize    the pool size
81       * @return             the activator
82       **********************************************************************************************************************************************************/
83      @Nonnull
84      public ActorActivator withPoolSize (@Nonnegative final int poolSize)
85        {
86          return new ActorActivator(actorClass, poolSize);
87        }
88  
89      /***********************************************************************************************************************************************************
90       *
91       **********************************************************************************************************************************************************/
92      private ActorActivator (@Nonnull final Class<?> actorClass, @Nonnegative final int poolSize)
93        {
94          this.actorClass = actorClass;
95          this.poolSize = poolSize;
96        }
97  
98      /***********************************************************************************************************************************************************
99       * Activates the managed actor.
100      **********************************************************************************************************************************************************/
101     public void initialize()
102       {
103         try
104           {
105             final var actor = actorClass.getAnnotation(Actor.class);
106             validate(actor);
107             actorObject = actorClass.getDeclaredConstructor().newInstance();
108             executor = new ExecutorWithPriority(poolSize, actorClass.getSimpleName(), actor.initialPriority());
109             mBeansManager = new MBeansManager(actorObject, poolSize);
110             messageBusAdapter = new CollaborationAwareMessageBusAdapter(actorObject, executor, mBeansManager.getStats());
111           }
112         catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e)
113           {
114             throw new RuntimeException(e);
115           }
116 
117         forEachMethodInTopDownHierarchy(actorObject, messageBusAdapter);
118         forEachMethodInTopDownHierarchy(actorObject, new PostConstructInvoker(actorObject));
119         mBeansManager.register();
120       }
121 
122     /***********************************************************************************************************************************************************
123      * Deactivates the managed actor and releases resources.
124      **********************************************************************************************************************************************************/
125     public void dispose()
126       {
127         mBeansManager.unregister();
128         forEachMethodInBottomUpHierarchy(actorObject, new PreDestroyInvoker(actorObject));
129         messageBusAdapter.unsubscribe();
130       }
131 
132     /***********************************************************************************************************************************************************
133      *
134      **********************************************************************************************************************************************************/
135     private void validate (@Nonnull final Actor actor)
136       {
137         //noinspection ConstantConditions
138         if (actor == null)
139           {
140             throw new IllegalArgumentException("Actor class must be annotated with @Actor: " + actorClass);
141           }
142 
143         if (!actor.threadSafe() && (poolSize != 1))
144           {
145             throw new IllegalArgumentException("Actors that aren't thread safe can't have pool size > 1");
146           }
147       }
148   }