org.springframework.aop.framework

Class ProxyFactoryBean

  • All Implemented Interfaces:
    java.io.Serializable, Advised, TargetClassAware, Aware, BeanClassLoaderAware, BeanFactoryAware, FactoryBean<java.lang.Object>


    public class ProxyFactoryBean
    extends ProxyCreatorSupport
    implements FactoryBean<java.lang.Object>, BeanClassLoaderAware, BeanFactoryAware
    FactoryBean implementation that builds an AOP proxy based on beans in Spring BeanFactory.

    MethodInterceptors and Advisors are identified by a list of bean names in the current bean factory, specified through the "interceptorNames" property. The last entry in the list can be the name of a target bean or a TargetSource; however, it is normally preferable to use the "targetName"/"target"/"targetSource" properties instead.

    Global interceptors and advisors can be added at the factory level. The specified ones are expanded in an interceptor list where an "xxx*" entry is included in the list, matching the given prefix with the bean names (e.g. "global*" would match both "globalBean1" and "globalBean2", "*" all defined interceptors). The matching interceptors get applied according to their returned order value, if they implement the Ordered interface.

    Creates a JDK proxy when proxy interfaces are given, and a CGLIB proxy for the actual target class if not. Note that the latter will only work if the target class does not have final methods, as a dynamic subclass will be created at runtime.

    It's possible to cast a proxy obtained from this factory to Advised, or to obtain the ProxyFactoryBean reference and programmatically manipulate it. This won't work for existing prototype references, which are independent. However, it will work for prototypes subsequently obtained from the factory. Changes to interception will work immediately on singletons (including existing references). However, to change interfaces or target it's necessary to obtain a new instance from the factory. This means that singleton instances obtained from the factory do not have the same object identity. However, they do have the same interceptors and target, and changing any reference will change all objects.

    Author:
    Rod Johnson, Juergen Hoeller
    See Also:
    setInterceptorNames(java.lang.String...), setProxyInterfaces(java.lang.Class<?>[]), MethodInterceptor, Advisor, Advised, Serialized Form
    • Field Detail

      • GLOBAL_SUFFIX

        public static final java.lang.String GLOBAL_SUFFIX
        This suffix in a value in an interceptor list indicates to expand globals.
        See Also:
        Constant Field Values
      • logger

        protected final Log logger
    • Constructor Detail

      • ProxyFactoryBean

        public ProxyFactoryBean()
    • Method Detail

      • setInterceptorNames

        public void setInterceptorNames(java.lang.String... interceptorNames)
        Set the list of Advice/Advisor bean names. This must always be set to use this factory bean in a bean factory.

        The referenced beans should be of type Interceptor, Advisor or Advice The last entry in the list can be the name of any bean in the factory. If it's neither an Advice nor an Advisor, a new SingletonTargetSource is added to wrap it. Such a target bean cannot be used if the "target" or "targetSource" or "targetName" property is set, in which case the "interceptorNames" array must contain only Advice/Advisor bean names.

        NOTE: Specifying a target bean as final name in the "interceptorNames" list is deprecated and will be removed in a future Spring version. Use the "targetName" property instead.

        See Also:
        MethodInterceptor, Advisor, Advice, SingletonTargetSource
      • setAutodetectInterfaces

        public void setAutodetectInterfaces(boolean autodetectInterfaces)
        Set whether to autodetect proxy interfaces if none specified.

        Default is "true". Turn this flag off to create a CGLIB proxy for the full target class if no interfaces specified.

        See Also:
        ProxyConfig.setProxyTargetClass(boolean)
      • setSingleton

        public void setSingleton(boolean singleton)
        Set the value of the singleton property. Governs whether this factory should always return the same proxy instance (which implies the same target) or whether it should return a new prototype instance, which implies that the target and interceptors may be new instances also, if they are obtained from prototype bean definitions. This allows for fine control of independence/uniqueness in the object graph.
      • setFrozen

        public void setFrozen(boolean frozen)
        Description copied from class: ProxyConfig
        Set whether this config should be frozen.

        When a config is frozen, no advice changes can be made. This is useful for optimization, and useful when we don't want callers to be able to manipulate configuration after casting to Advised.

        Overrides:
        setFrozen in class ProxyConfig
      • setProxyClassLoader

        public void setProxyClassLoader(@Nullable
                                        java.lang.ClassLoader classLoader)
        Set the ClassLoader to generate the proxy class in.

        Default is the bean ClassLoader, i.e. the ClassLoader used by the containing BeanFactory for loading all bean classes. This can be overridden here for specific proxies.

      • getObject

        @Nullable
        public java.lang.Object getObject()
                                             throws BeansException
        Return a proxy. Invoked when clients obtain beans from this factory bean. Create an instance of the AOP proxy to be returned by this factory. The instance will be cached for a singleton, and create on each call to getObject() for a proxy.
        Specified by:
        getObject in interface FactoryBean<java.lang.Object>
        Returns:
        a fresh AOP proxy reflecting the current state of this factory
        Throws:
        BeansException
        See Also:
        FactoryBeanNotInitializedException
      • getObjectType

        public java.lang.Class<?> getObjectType()
        Return the type of the proxy. Will check the singleton instance if already created, else fall back to the proxy interface (in case of just a single one), the target bean type, or the TargetSource's target class.
        Specified by:
        getObjectType in interface FactoryBean<java.lang.Object>
        Returns:
        the type of object that this FactoryBean creates, or null if not known at the time of the call
        See Also:
        TargetSource.getTargetClass()
      • isSingleton

        public boolean isSingleton()
        Description copied from interface: FactoryBean
        Is the object managed by this factory a singleton? That is, will FactoryBean.getObject() always return the same object (a reference that can be cached)?

        NOTE: If a FactoryBean indicates to hold a singleton object, the object returned from getObject() might get cached by the owning BeanFactory. Hence, do not return true unless the FactoryBean always exposes the same reference.

        The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.

        NOTE: This method returning false does not necessarily indicate that returned objects are independent instances. An implementation of the extended SmartFactoryBean interface may explicitly indicate independent instances through its SmartFactoryBean.isPrototype() method. Plain FactoryBean implementations which do not implement this extended interface are simply assumed to always return independent instances if the isSingleton() implementation returns false.

        The default implementation returns true, since a FactoryBean typically manages a singleton instance.

        Specified by:
        isSingleton in interface FactoryBean<java.lang.Object>
        Returns:
        whether the exposed object is a singleton
        See Also:
        FactoryBean.getObject(), SmartFactoryBean.isPrototype()
      • createCompositeInterface

        protected java.lang.Class<?> createCompositeInterface(java.lang.Class<?>[] interfaces)
        Create a composite interface Class for the given interfaces, implementing the given interfaces in one single Class.

        The default implementation builds a JDK proxy class for the given interfaces.

        Parameters:
        interfaces - the interfaces to merge
        Returns:
        the merged interface as Class
        See Also:
        Proxy.getProxyClass(java.lang.ClassLoader, java.lang.Class<?>...)
      • getProxy

        protected java.lang.Object getProxy(AopProxy aopProxy)
        Return the proxy object to expose.

        The default implementation uses a getProxy call with the factory's bean class loader. Can be overridden to specify a custom class loader.

        Parameters:
        aopProxy - the prepared AopProxy instance to get the proxy from
        Returns:
        the proxy object to expose
        See Also:
        AopProxy.getProxy(ClassLoader)