LazyInitTargetSourceCreator


1   /*
2    * Copyright 2002-2006 the original author or authors.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.springframework.aop.framework.autoproxy.target;
18  
19  import org.springframework.aop.target.AbstractBeanFactoryBasedTargetSource;
20  import org.springframework.aop.target.LazyInitTargetSource;
21  import org.springframework.beans.factory.config.BeanDefinition;
22  import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
23  
24  /**
25   * TargetSourceCreator that enforces a LazyInitTargetSource for each bean
26   * that is defined as "lazy-init". This will lead to a proxy created for
27   * each of those beans, allowing to fetch a reference to such a bean
28   * without actually initialized the target bean instance.
29   *
30   * <p>To be registered as custom TargetSourceCreator for an auto-proxy creator,
31   * in combination with custom interceptors for specific beans or for the
32   * creation of lazy-init proxies only. For example, as autodetected
33   * infrastructure bean in an XML application context definition:
34   *
35   * <pre class="code">
36   * &lt;bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator"&gt;
37   *   &lt;property name="customTargetSourceCreators"&gt;
38   *     &lt;list&gt;
39   *       &lt;bean class="org.springframework.aop.framework.autoproxy.target.LazyInitTargetSourceCreator"/&gt;
40   *     &lt;/list&gt;
41   *   &lt;/property&gt;
42   * &lt;/bean&gt;
43   *
44   * &lt;bean id="myLazyInitBean" class="mypackage.MyBeanClass" lazy-init="true"&gt;
45   *   ...
46   * &lt;/bean&gt;</pre>
47   *
48   * @author Juergen Hoeller
49   * @since 1.2
50   * @see org.springframework.beans.factory.config.BeanDefinition#isLazyInit
51   * @see org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator#setCustomTargetSourceCreators
52   * @see org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator
53   */
54  public class LazyInitTargetSourceCreator extends AbstractBeanFactoryBasedTargetSourceCreator {
55  
56      protected boolean isPrototypeBased() {
57          return false;
58      }
59  
60      protected AbstractBeanFactoryBasedTargetSource createBeanFactoryBasedTargetSource(
61              Class   beanClass, String   beanName) {
62  
63          if (getBeanFactory() instanceof ConfigurableListableBeanFactory) {
64              BeanDefinition definition =
65                      ((ConfigurableListableBeanFactory) getBeanFactory()).getBeanDefinition(beanName);
66              if (definition.isLazyInit()) {
67                  return new LazyInitTargetSource();
68              }
69          }
70          return null;
71      }
72  
73  }
74
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