Class AbstractFactoryBean<T>

    • Field Detail

      • logger

        protected final Log logger
        Logger available to subclasses
    • Method Detail

      • setSingleton

        public void setSingleton​(boolean singleton)
        Set if a singleton should be created, or a new object on each request otherwise. Default is true (a singleton).
      • 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.

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

        public abstract Class<?> getObjectType()
        This abstract method declaration mirrors the method in the FactoryBean interface, for a consistent offering of abstract template methods.
        Specified by:
        getObjectType in interface FactoryBean<T>
        Returns:
        the type of object that this FactoryBean creates, or null if not known at the time of the call
        See Also:
        FactoryBean.getObjectType()
      • createInstance

        protected abstract T createInstance()
                                     throws Exception
        Template method that subclasses must override to construct the object returned by this factory.

        Invoked on initialization of this FactoryBean in case of a singleton; else, on each getObject() call.

        Returns:
        the object returned by this factory
        Throws:
        Exception - if an exception occurred during object creation
        See Also:
        getObject()
      • getEarlySingletonInterfaces

        protected Class<?>[] getEarlySingletonInterfaces()
        Return an array of interfaces that a singleton object exposed by this FactoryBean is supposed to implement, for use with an 'early singleton proxy' that will be exposed in case of a circular reference.

        The default implementation returns this FactoryBean's object type, provided that it is an interface, or null otherwise. The latter indicates that early singleton access is not supported by this FactoryBean. This will lead to a FactoryBeanNotInitializedException getting thrown.

        Returns:
        the interfaces to use for 'early singletons', or null to indicate a FactoryBeanNotInitializedException
        See Also:
        FactoryBeanNotInitializedException
      • destroyInstance

        protected void destroyInstance​(T instance)
                                throws Exception
        Callback for destroying a singleton instance. Subclasses may override this to destroy the previously created instance.

        The default implementation is empty.

        Parameters:
        instance - the singleton instance, as returned by createInstance()
        Throws:
        Exception - in case of shutdown errors
        See Also:
        createInstance()