| org.springframework.beans.factory.BeanFactory
| BeanFactory | | public interface BeanFactory (Code) | | The root interface for accessing a Spring bean container.
This is the basic client view of a bean container;
further interfaces such as
ListableBeanFactory and
org.springframework.beans.factory.config.ConfigurableBeanFactory are available for specific purposes.
This interface is implemented by objects that hold a number of bean definitions,
each uniquely identified by a String name. Depending on the bean definition,
the factory will return either an independent instance of a contained object
(the Prototype design pattern), or a single shared instance (a superior
alternative to the Singleton design pattern, in which the instance is a
singleton in the scope of the factory). Which type of instance will be returned
depends on the bean factory configuration: the API is the same. Since Spring
2.0, further scopes are available depending on the concrete application
context (e.g. "request" and "session" scopes in a web environment).
The point of this approach is that the BeanFactory is a central registry
of application components, and centralizes configuration of application
components (no more do individual objects need to read properties files,
for example). See chapters 4 and 11 of "Expert One-on-One J2EE Design and
Development" for a discussion of the benefits of this approach.
Note that it is generally better to rely on Dependency Injection
("push" configuration) to configure application objects through setters
or constructors, rather than use any form of "pull" configuration like a
BeanFactory lookup. Spring's Dependency Injection functionality is
implemented using this BeanFactory interface and its subinterfaces.
Normally a BeanFactory will load bean definitions stored in a configuration
source (such as an XML document), and use the org.springframework.beans
package to configure the beans. However, an implementation could simply return
Java objects it creates as necessary directly in Java code. There are no
constraints on how the definitions could be stored: LDAP, RDBMS, XML,
properties file, etc. Implementations are encouraged to support references
amongst beans (Dependency Injection).
In contrast to the methods in
ListableBeanFactory , all of the
operations in this interface will also check parent factories if this is a
HierarchicalBeanFactory . If a bean is not found in this factory instance,
the immediate parent factory will be asked. Beans in this factory instance
are supposed to override beans of the same name in any parent factory.
Bean factory implementations should support the standard bean lifecycle interfaces
as far as possible. The full set of initialization methods and their standard order is:
1. BeanNameAware's setBeanName
2. BeanClassLoaderAware's setBeanClassLoader
3. BeanFactoryAware's setBeanFactory
4. ResourceLoaderAware's setResourceLoader
(only applicable when running in an application context)
5. ApplicationEventPublisherAware's setApplicationEventPublisher
(only applicable when running in an application context)
6. MessageSourceAware's setMessageSource
(only applicable when running in an application context)
7. ApplicationContextAware's setApplicationContext
(only applicable when running in an application context)
8. ServletContextAware's setServletContext
(only applicable when running in a web application context)
9. postProcessBeforeInitialization methods of BeanPostProcessors
10. InitializingBean's afterPropertiesSet
11. a custom init-method definition
12. postProcessAfterInitialization methods of BeanPostProcessors
On shutdown of a bean factory, the following lifecycle methods apply:
1. DisposableBean's destroy
2. a custom destroy-method definition
author:
Rod Johnson
author:
Juergen Hoeller
since:
13 April 2001
See Also: BeanNameAware.setBeanName
See Also: BeanClassLoaderAware.setBeanClassLoader
See Also: BeanFactoryAware.setBeanFactory
See Also: org.springframework.context.ResourceLoaderAware.setResourceLoader
See Also: org.springframework.context.ApplicationEventPublisherAware.setApplicationEventPublisher
See Also: org.springframework.context.MessageSourceAware.setMessageSource
See Also: org.springframework.context.ApplicationContextAware.setApplicationContext
See Also: org.springframework.web.context.ServletContextAware.setServletContext
See Also: org.springframework.beans.factory.config.BeanPostProcessor.postProcessBeforeInitialization
See Also: InitializingBean.afterPropertiesSet
See Also: org.springframework.beans.factory.support.RootBeanDefinition.getInitMethodName
See Also: org.springframework.beans.factory.config.BeanPostProcessor.postProcessAfterInitialization
See Also: DisposableBean.destroy
See Also: org.springframework.beans.factory.support.RootBeanDefinition.getDestroyMethodName |
| Method Summary | |
| boolean | containsBean(String name)
Does this bean factory contain a bean with the given name? More specifically,
is
BeanFactory.getBean able to obtain a bean instance for the given name?
Translates aliases back to the corresponding canonical bean name. | | String[] | getAliases(String name)
Return the aliases for the given bean name, if any. | | Object | getBean(String name)
Return an instance, which may be shared or independent, of the specified bean.
This method allows a Spring BeanFactory to be used as a replacement for the
Singleton or Prototype design pattern. | | Object | getBean(String name, Class requiredType)
Return an instance, which may be shared or independent, of the specified bean.
Behaves the same as
BeanFactory.getBean(String) , but provides a measure of type
safety by throwing a BeanNotOfRequiredTypeException if the bean is not of the
required type. | | Class | getType(String name)
Determine the type of the bean with the given name. | | boolean | isPrototype(String name)
Is this bean a prototype? That is, will
BeanFactory.getBean always return
independent instances?
Note: This method returning false does not clearly indicate
a singleton object. | | boolean | isSingleton(String name)
Is this bean a shared singleton? That is, will
BeanFactory.getBean always
return the same instance?
Note: This method returning false does not clearly indicate
independent instances. | | boolean | isTypeMatch(String name, Class targetType)
Check whether the bean with the given name matches the specified type. |
| FACTORY_BEAN_PREFIX | | String FACTORY_BEAN_PREFIX(Code) | | Used to dereference a
FactoryBean instance and distinguish it from
beans created by the FactoryBean. For example, if the bean named
myJndiObject is a FactoryBean, getting &myJndiObject
will return the factory, not the instance returned by the factory.
|
| containsBean | | boolean containsBean(String name)(Code) | | Does this bean factory contain a bean with the given name? More specifically,
is
BeanFactory.getBean able to obtain a bean instance for the given name?
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to query whether a bean with the given name is defined |
| getAliases | | String[] getAliases(String name)(Code) | | Return the aliases for the given bean name, if any.
All of those aliases point to the same bean when used in a
BeanFactory.getBean call.
If the given name is an alias, the corresponding original bean name
and other aliases (if any) will be returned, with the original bean name
being the first element in the array.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the bean name to check for aliases the aliases, or an empty array if none
See Also: BeanFactory.getBean |
| getBean | | Object getBean(String name) throws BeansException(Code) | | Return an instance, which may be shared or independent, of the specified bean.
This method allows a Spring BeanFactory to be used as a replacement for the
Singleton or Prototype design pattern. Callers may retain references to
returned objects in the case of Singleton beans.
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to retrieve an instance of the bean
throws:
NoSuchBeanDefinitionException - if there is no bean definitionwith the specified name
throws:
BeansException - if the bean could not be obtained |
| getBean | | Object getBean(String name, Class requiredType) throws BeansException(Code) | | Return an instance, which may be shared or independent, of the specified bean.
Behaves the same as
BeanFactory.getBean(String) , but provides a measure of type
safety by throwing a BeanNotOfRequiredTypeException if the bean is not of the
required type. This means that ClassCastException can't be thrown on casting
the result correctly, as can happen with
BeanFactory.getBean(String) .
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to retrieve
Parameters:
requiredType - type the bean must match. Can be an interface or superclassof the actual class, or null for any match. For example, if the valueis Object.class, this method will succeed whatever the class of thereturned instance. an instance of the bean
throws:
BeanNotOfRequiredTypeException - if the bean is not of the required type
throws:
NoSuchBeanDefinitionException - if there's no such bean definition
throws:
BeansException - if the bean could not be created |
| isPrototype | | boolean isPrototype(String name) throws NoSuchBeanDefinitionException(Code) | | Is this bean a prototype? That is, will
BeanFactory.getBean always return
independent instances?
Note: This method returning false does not clearly indicate
a singleton object. It indicates non-independent instances, which may correspond
to a scoped bean as well. Use the
BeanFactory.isSingleton operation to explicitly
check for a shared singleton instance.
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to query whether this bean will always deliver independent instances
throws:
NoSuchBeanDefinitionException - if there is no bean with the given name
since:
2.0.3
See Also: BeanFactory.getBean
See Also: BeanFactory.isSingleton |
| isSingleton | | boolean isSingleton(String name) throws NoSuchBeanDefinitionException(Code) | | Is this bean a shared singleton? That is, will
BeanFactory.getBean always
return the same instance?
Note: This method returning false does not clearly indicate
independent instances. It indicates non-singleton instances, which may correspond
to a scoped bean as well. Use the
BeanFactory.isPrototype operation to explicitly
check for independent instances.
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to query whether this bean corresponds to a singleton instance
throws:
NoSuchBeanDefinitionException - if there is no bean with the given name
See Also: BeanFactory.getBean
See Also: BeanFactory.isPrototype |
| isTypeMatch | | boolean isTypeMatch(String name, Class targetType) throws NoSuchBeanDefinitionException(Code) | | Check whether the bean with the given name matches the specified type.
More specifically, check whether a
BeanFactory.getBean call for the given name
would return an object that is assignable to the specified target type.
Translates aliases back to the corresponding canonical bean name.
Will ask the parent factory if the bean cannot be found in this factory instance.
Parameters:
name - the name of the bean to query
Parameters:
targetType - the type to match against true if the bean type matches,false if it doesn't match or cannot be determined yet
throws:
NoSuchBeanDefinitionException - if there is no bean with the given name
since:
2.0.1
See Also: BeanFactory.getBean
See Also: BeanFactory.getType |
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