org.springframework.aop.framework.autoproxy
Class AbstractAutoProxyCreator

java.lang.Object
  extended by org.springframework.aop.framework.ProxyConfig
      extended by org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator
All Implemented Interfaces:
Serializable, BeanFactoryAware, BeanPostProcessor, InstantiationAwareBeanPostProcessor, Ordered
Direct Known Subclasses:
AbstractAdvisorAutoProxyCreator, BeanNameAutoProxyCreator

public abstract class AbstractAutoProxyCreator
extends ProxyConfig
implements InstantiationAwareBeanPostProcessor, BeanFactoryAware, Ordered

BeanPostProcessor implementation that wraps each eligible bean with an AOP proxy, delegating to specified interceptors before invoking the bean itself.

This class distinguishes between "common" interceptors: shared for all proxies it creates, and "specific" interceptors: unique per bean instance. There need not be any common interceptors. If there are, they are set using the interceptorNames property. As with ProxyFactoryBean, interceptors names in the current factory are used rather than bean references to allow correct handling of prototype advisors and interceptors: for example, to support stateful mixins. Any advice type is supported for "interceptorNames" entries.

Such auto-proxying is particularly useful if there's a large number of beans that need to be wrapped with similar proxies, i.e. delegating to the same interceptors. Instead of x repetitive proxy definitions for x target beans, you can register one single such post processor with the bean factory to achieve the same effect.

Subclasses can apply any strategy to decide if a bean is to be proxied, e.g. by type, by name, by definition details, etc. They can also return additional interceptors that should just be applied to the specific bean instance. The default concrete implementation is BeanNameAutoProxyCreator, identifying the beans to be proxied via a list of bean names.

Any number of TargetSourceCreator implementations can be used to create a custom target source - for example, to pool prototype objects. Auto-proxying will occur even if there is no advice, as long as a TargetSourceCreator specifies a custom TargetSource. If there are no TargetSourceCreators set, or if none matches, a SingletonTargetSource will be used by default to wrap the target bean instance.

Since:
13.10.2003
Author:
Juergen Hoeller, Rod Johnson, Rob Harrop
See Also:
setInterceptorNames(java.lang.String[]), getAdvicesAndAdvisorsForBean(java.lang.Class, java.lang.String, org.springframework.aop.TargetSource), BeanNameAutoProxyCreator, DefaultAdvisorAutoProxyCreator, Serialized Form

Field Summary
protected static Object[] DO_NOT_PROXY
          Convenience constant for subclasses: Return value for "do not proxy".
protected static Object[] PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS
          Convenience constant for subclasses: Return value for "proxy without additional interceptors, just the common ones".
 
Fields inherited from class org.springframework.aop.framework.ProxyConfig
exposeProxy, logger
 
Constructor Summary
AbstractAutoProxyCreator()
           
 
Method Summary
protected  Object createProxy(Class beanClass, String beanName, Object[] specificInterceptors, TargetSource targetSource)
          Create an AOP proxy for the given bean.
protected  void customizeProxyFactory(ProxyFactory proxyFactory)
          Subclasses may choose to implement this: for example, to change the interfaces exposed.
protected abstract  Object[] getAdvicesAndAdvisorsForBean(Class beanClass, String beanName, TargetSource customTargetSource)
          Return whether the given bean is to be proxied, what additional advices (e.g.
protected  BeanFactory getBeanFactory()
          Return the owning BeanFactory May be null, as this object doesn't need to belong to a bean factory.
protected  TargetSource getCustomTargetSource(Class beanClass, String beanName)
          Create a target source for bean instances.
 int getOrder()
          Return the order value of this object, higher value meaning greater in terms of sorting.
 boolean isFrozen()
          Return whether the config is frozen, and no advice changes can be made.
protected  boolean isInfrastructureClass(Class beanClass, String beanName)
          Return whether the given bean class represents an infrastructure class that should never be proxied.
 Object postProcessAfterInitialization(Object bean, String beanName)
          Create a proxy with the configured interceptors if the bean is identified as one to proxy by the subclass.
 Object postProcessBeforeInitialization(Object bean, String beanName)
          Apply this BeanPostProcessor to the given new bean instance before any bean initialization callbacks (like InitializingBean's afterPropertiesSet or a custom init-method).
 Object postProcessBeforeInstantiation(Class beanClass, String beanName)
          Apply this BeanPostProcessor before the target bean gets instantiated.
 void setAdvisorAdapterRegistry(AdvisorAdapterRegistry advisorAdapterRegistry)
          Specify the AdvisorAdapterRegistry to use.
 void setApplyCommonInterceptorsFirst(boolean applyCommonInterceptorsFirst)
          Set whether the common interceptors should be applied before bean-specific ones.
 void setBeanFactory(BeanFactory beanFactory)
          Callback that supplies the owning factory to a bean instance.
 void setCustomTargetSourceCreators(TargetSourceCreator[] targetSourceCreators)
          Set custom TargetSourceCreators to be applied in this order.
 void setFrozen(boolean frozen)
          Set whether or not the proxy should be frozen, preventing advice from being added to it once it is created.
 void setInterceptorNames(String[] interceptorNames)
          Set the common interceptors.
 void setOrder(int order)
          Set the ordering which will apply to this class's implementation of Ordered, used when applying multiple BeanPostProcessors.
protected  boolean shouldSkip(Class beanClass, String beanName)
          Subclasses should override this method to return true if the given bean should not be considered for auto-proxying by this post-processor.
 
Methods inherited from class org.springframework.aop.framework.ProxyConfig
copyFrom, getAopProxyFactory, isExposeProxy, isOpaque, isOptimize, isProxyTargetClass, setAopProxyFactory, setExposeProxy, setOpaque, setOptimize, setProxyTargetClass, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

DO_NOT_PROXY

protected static final Object[] DO_NOT_PROXY
Convenience constant for subclasses: Return value for "do not proxy".

See Also:
getAdvicesAndAdvisorsForBean(java.lang.Class, java.lang.String, org.springframework.aop.TargetSource)

PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS

protected static final Object[] PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS
Convenience constant for subclasses: Return value for "proxy without additional interceptors, just the common ones".

See Also:
getAdvicesAndAdvisorsForBean(java.lang.Class, java.lang.String, org.springframework.aop.TargetSource)
Constructor Detail

AbstractAutoProxyCreator

public AbstractAutoProxyCreator()
Method Detail

setOrder

public final void setOrder(int order)
Set the ordering which will apply to this class's implementation of Ordered, used when applying multiple BeanPostProcessors. Default value is Integer.MAX_VALUE, meaning that it's non-ordered.

Parameters:
order - ordering value

getOrder

public final int getOrder()
Description copied from interface: Ordered
Return the order value of this object, higher value meaning greater in terms of sorting. Normally starting with 0 or 1, Integer.MAX_VALUE indicating greatest. Same order values will result in arbitrary positions for the affected objects.

Higher value can be interpreted as lower priority, consequently the first object has highest priority (somewhat analogous to Servlet "load-on-startup" values).

Specified by:
getOrder in interface Ordered
Returns:
the order value

setFrozen

public void setFrozen(boolean frozen)
Set whether or not the proxy should be frozen, preventing advice from being added to it once it is created.

Overridden from the super class to prevent the proxy configuration from being frozen before the proxy is created.

Overrides:
setFrozen in class ProxyConfig

isFrozen

public boolean isFrozen()
Description copied from class: ProxyConfig
Return whether the config is frozen, and no advice changes can be made.

Overrides:
isFrozen in class ProxyConfig

setAdvisorAdapterRegistry

public void setAdvisorAdapterRegistry(AdvisorAdapterRegistry advisorAdapterRegistry)
Specify the AdvisorAdapterRegistry to use. Default is the global AdvisorAdapterRegistry.

See Also:
GlobalAdvisorAdapterRegistry

setCustomTargetSourceCreators

public void setCustomTargetSourceCreators(TargetSourceCreator[] targetSourceCreators)
Set custom TargetSourceCreators to be applied in this order. If the list is empty, or they all return null, a SingletonTargetSource will be created for each bean.

Note that TargetSourceCreators will kick in even for target beans where no advices or advisors have been found. If a TargetSourceCreator returns a TargetSource for a specific bean, that bean will be proxied in any case.

TargetSourceCreators can only be invoked if this post processor is used in a BeanFactory, and its BeanFactoryAware callback is used.

Parameters:
targetSourceCreators - list of TargetSourceCreator. Ordering is significant: The TargetSource returned from the first matching TargetSourceCreator (that is, the first that returns non-null) will be used.

setInterceptorNames

public void setInterceptorNames(String[] interceptorNames)
Set the common interceptors. These must be bean names in the current factory. They can be of any advice or advisor type Spring supports.

If this property isn't set, there will be zero common interceptors. This is perfectly valid, if "specific" interceptors such as matching Advisors are all we want.


setApplyCommonInterceptorsFirst

public void setApplyCommonInterceptorsFirst(boolean applyCommonInterceptorsFirst)
Set whether the common interceptors should be applied before bean-specific ones. Default is "true"; else, bean-specific interceptors will get applied first.


setBeanFactory

public void setBeanFactory(BeanFactory beanFactory)
Description copied from interface: BeanFactoryAware
Callback that supplies the owning factory to a bean instance.

Invoked after the population of normal bean properties but before an initialization callback such as InitializingBean.afterPropertiesSet() or a custom init-method.

Specified by:
setBeanFactory in interface BeanFactoryAware
Parameters:
beanFactory - owning BeanFactory (never null). The bean can immediately call methods on the factory.
See Also:
BeanInitializationException

getBeanFactory

protected BeanFactory getBeanFactory()
Return the owning BeanFactory May be null, as this object doesn't need to belong to a bean factory.


postProcessBeforeInstantiation

public Object postProcessBeforeInstantiation(Class beanClass,
                                             String beanName)
                                      throws BeansException
Description copied from interface: InstantiationAwareBeanPostProcessor
Apply this BeanPostProcessor before the target bean gets instantiated. The returned bean object may be a proxy to use instead of the target bean, effectively suppressing default instantiation of the target bean.

If a non-null object is returned by this method, the bean creation process will be short-circuited. The returned bean object will not be processed any further; in particular, no further BeanPostProcessor callbacks will be applied to it. This mechanism is mainly intended for exposing a proxy instead of an actual target bean.

This callback will only be applied to bean definitions with a bean class. In particular, it will not be applied to beans with a "factory-method".

Specified by:
postProcessBeforeInstantiation in interface InstantiationAwareBeanPostProcessor
Parameters:
beanClass - the class of the bean to be instantiated
beanName - the name of the bean
Returns:
the bean object to expose instead of a default instance of the target bean
Throws:
BeansException - in case of errors
See Also:
AbstractBeanDefinition.hasBeanClass(), AbstractBeanDefinition.getFactoryMethodName()

postProcessBeforeInitialization

public Object postProcessBeforeInitialization(Object bean,
                                              String beanName)
Description copied from interface: BeanPostProcessor
Apply this BeanPostProcessor to the given new bean instance before any bean initialization callbacks (like InitializingBean's afterPropertiesSet or a custom init-method). The bean will already be populated with property values. The returned bean instance may be a wrapper around the original.

Specified by:
postProcessBeforeInitialization in interface BeanPostProcessor
Parameters:
bean - the new bean instance
beanName - the name of the bean
Returns:
the bean instance to use, either the original or a wrapped one
See Also:
InitializingBean.afterPropertiesSet()

postProcessAfterInitialization

public Object postProcessAfterInitialization(Object bean,
                                             String beanName)
                                      throws BeansException
Create a proxy with the configured interceptors if the bean is identified as one to proxy by the subclass.

Specified by:
postProcessAfterInitialization in interface BeanPostProcessor
Parameters:
bean - the new bean instance
beanName - the name of the bean
Returns:
the bean instance to use, either the original or a wrapped one
Throws:
BeansException - in case of errors
See Also:
getAdvicesAndAdvisorsForBean(java.lang.Class, java.lang.String, org.springframework.aop.TargetSource)

isInfrastructureClass

protected boolean isInfrastructureClass(Class beanClass,
                                        String beanName)
Return whether the given bean class represents an infrastructure class that should never be proxied.

Default implementation considers Advisors, Advices and AbstractAutoProxyCreators as infrastructure classes.

Parameters:
beanClass - the class of the bean
beanName - the name of the bean
Returns:
whether the bean represents an infrastructure class
See Also:
Advisor, MethodInterceptor, shouldSkip(java.lang.Class, java.lang.String)

shouldSkip

protected boolean shouldSkip(Class beanClass,
                             String beanName)
Subclasses should override this method to return true if the given bean should not be considered for auto-proxying by this post-processor.

Sometimes we need to be able to avoid this happening if it will lead to a circular reference. This implementation returns false.

Parameters:
beanClass - the class of the bean
beanName - the name of the bean

getCustomTargetSource

protected TargetSource getCustomTargetSource(Class beanClass,
                                             String beanName)
Create a target source for bean instances. Uses any TargetSourceCreators if set. Returns null if no custom TargetSource should be used.

This implementation uses the "customTargetSourceCreators" property. Subclasses can override this method to use a different mechanism.

Parameters:
beanClass - the class of the bean to create a TargetSource for
beanName - the name of the bean
Returns:
a TargetSource for this bean
See Also:
setCustomTargetSourceCreators(org.springframework.aop.framework.autoproxy.TargetSourceCreator[])

createProxy

protected Object createProxy(Class beanClass,
                             String beanName,
                             Object[] specificInterceptors,
                             TargetSource targetSource)
Create an AOP proxy for the given bean.

Parameters:
beanClass - the class of the bean
beanName - the name of the bean
specificInterceptors - the set of interceptors that is specific to this bean (may be empty, but not null)
targetSource - the TargetSource for the proxy, already pre-configured to access the bean
Returns:
the AOP proxy for the bean

customizeProxyFactory

protected void customizeProxyFactory(ProxyFactory proxyFactory)
Subclasses may choose to implement this: for example, to change the interfaces exposed.

The default implementation is empty.

Parameters:
proxyFactory - ProxyFactory that is already configured with TargetSource and interfaces and will be used to create the proxy immediably after this method returns

getAdvicesAndAdvisorsForBean

protected abstract Object[] getAdvicesAndAdvisorsForBean(Class beanClass,
                                                         String beanName,
                                                         TargetSource customTargetSource)
                                                  throws BeansException
Return whether the given bean is to be proxied, what additional advices (e.g. AOP Alliance interceptors) and advisors to apply.

The previous name of this method was "getInterceptorAndAdvisorForBean". It has been renamed in the course of general terminology clarification in Spring 1.1. An AOP Alliance Interceptor is just a special form of Advice, so the generic Advice term is preferred now.

The third parameter, customTargetSource, is new in Spring 1.1; add it to existing implementations of this method.

Parameters:
beanClass - the class of the bean to advise
beanName - the name of the bean
customTargetSource - the TargetSource returned by the getCustomTargetSource(java.lang.Class, java.lang.String) method: may be ignored. Will be null if no custom target source is in use.
Returns:
an array of additional interceptors for the particular bean; or an empty array if no additional interceptors but just the common ones; or null if no proxy at all, not even with the common interceptors. See constants DO_NOT_PROXY and PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS.
Throws:
BeansException - in case of errors
See Also:
DO_NOT_PROXY, PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS


Copyright (c) 2002-2007 The Spring Framework Project.