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1   package org.codehaus.plexus.component.manager;
2   
3   /*
4    * Copyright 2001-2006 Codehaus Foundation.
5    *
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * You may obtain a copy of the License at
9    *
10   *      http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  import java.util.Collections;
20  import java.util.HashMap;
21  import java.util.Iterator;
22  import java.util.Map;
23  import java.util.Map.Entry;
24  
25  import org.codehaus.plexus.MutablePlexusContainer;
26  import org.codehaus.plexus.classworlds.realm.ClassRealm;
27  import org.codehaus.plexus.component.builder.AbstractComponentBuildListener;
28  import org.codehaus.plexus.component.builder.ComponentBuilder;
29  import org.codehaus.plexus.component.builder.XBeanComponentBuilder;
30  import org.codehaus.plexus.component.factory.ComponentInstantiationException;
31  import org.codehaus.plexus.component.repository.ComponentDescriptor;
32  import org.codehaus.plexus.component.repository.exception.ComponentLifecycleException;
33  import org.codehaus.plexus.lifecycle.LifecycleHandler;
34  import org.codehaus.plexus.logging.Logger;
35  import org.codehaus.plexus.personality.plexus.lifecycle.phase.PhaseExecutionException;
36  
37  public abstract class AbstractComponentManager<T> implements ComponentManager<T> {
38      protected final MutablePlexusContainer container;
39  
40      private final ClassRealm realm;
41  
42      protected final ComponentDescriptor<T> componentDescriptor;
43  
44      private final Class<? extends T> type;
45  
46      private final String role;
47  
48      private final String roleHint;
49  
50      protected final ComponentBuilder<T> builder = new XBeanComponentBuilder<T>(this);
51  
52      private final LifecycleHandler lifecycleHandler;
53  
54      /**
55       * Contains a mapping from singleton instances to the realms
56       * they were used to configure with. This realm will be used to
57       * call all lifecycle methods.
58       * This will define a synchronized map, make sure to synchronize the map when iterating.
59       */
60      protected final Map<Object, ClassRealm> componentContextRealms =
61              Collections.synchronizedMap(new HashMap<Object, ClassRealm>());
62  
63      private int connections;
64  
65      private long startId;
66  
67      public AbstractComponentManager(
68              MutablePlexusContainer container,
69              LifecycleHandler lifecycleHandler,
70              ComponentDescriptor<T> componentDescriptor,
71              String role,
72              String roleHint) {
73          if (container == null) {
74              throw new NullPointerException("container is null");
75          }
76          this.container = container;
77  
78          if (lifecycleHandler == null) {
79              throw new NullPointerException("lifecycleHandler is null");
80          }
81          this.lifecycleHandler = lifecycleHandler;
82  
83          if (componentDescriptor == null) {
84              throw new NullPointerException("componentDescriptor is null");
85          }
86          this.componentDescriptor = componentDescriptor;
87  
88          if (role == null) {
89              throw new NullPointerException("role is null");
90          }
91          this.role = role;
92  
93          if (roleHint == null) {
94              throw new NullPointerException("roleHint is null");
95          }
96          this.roleHint = roleHint;
97  
98          this.realm = componentDescriptor.getRealm();
99  
100         this.type = componentDescriptor.getImplementationClass();
101     }
102 
103     public ComponentDescriptor<T> getComponentDescriptor() {
104         return componentDescriptor;
105     }
106 
107     public Class<? extends T> getType() {
108         return type;
109     }
110 
111     public ClassRealm getRealm() {
112         return realm;
113     }
114 
115     public String getRole() {
116         return role;
117     }
118 
119     public String getRoleHint() {
120         return roleHint;
121     }
122 
123     public LifecycleHandler getLifecycleHandler() {
124         return lifecycleHandler;
125     }
126 
127     protected void incrementConnectionCount() {
128         connections++;
129     }
130 
131     protected void decrementConnectionCount() {
132         connections--;
133     }
134 
135     protected boolean connected() {
136         return connections > 0;
137     }
138 
139     public int getConnections() {
140         return connections;
141     }
142 
143     // ----------------------------------------------------------------------
144     // Lifecylce Management
145     // ----------------------------------------------------------------------
146 
147     public void start(Object component) throws PhaseExecutionException {
148         startId = NEXT_START_ID.getAndIncrement();
149         getLifecycleHandler().start(component, this, componentDescriptor.getRealm());
150     }
151 
152     /**
153      * @deprecated for internal use only.. will be removed
154      */
155     public long getStartId() {
156         return startId;
157     }
158 
159     protected T createComponentInstance() throws ComponentInstantiationException, ComponentLifecycleException {
160         return builder.build(componentDescriptor, realm, new AbstractComponentBuildListener() {
161             public void componentCreated(
162                     ComponentDescriptor<?> componentDescriptor, Object component, ClassRealm realm) {
163                 componentContextRealms.put(component, realm);
164             }
165         });
166     }
167 
168     protected void endComponentLifecycle(Object component) throws ComponentLifecycleException {
169         ClassRealm contextRealm = componentContextRealms.remove(component);
170         if (contextRealm == null) {
171             contextRealm = container.getLookupRealm(component);
172         }
173 
174         try {
175             getLifecycleHandler().end(component, this, contextRealm);
176         } catch (PhaseExecutionException e) {
177             throw new ComponentLifecycleException("Error ending component lifecycle", e);
178         }
179     }
180 
181     public MutablePlexusContainer getContainer() {
182         return container;
183     }
184 
185     public Logger getLogger() {
186         return container.getLogger();
187     }
188 
189     public void dissociateComponentRealm(ClassRealm realm) throws ComponentLifecycleException {
190         synchronized (componentContextRealms) {
191             for (Iterator<Entry<Object, ClassRealm>> iterator =
192                             componentContextRealms.entrySet().iterator();
193                     iterator.hasNext(); ) {
194                 Entry<Object, ClassRealm> entry = iterator.next();
195                 ClassRealm componentRealm = entry.getValue();
196 
197                 if (componentRealm.getId().equals(realm.getId())) {
198                     iterator.remove();
199                 }
200             }
201         }
202     }
203 }