org.springframework.beans.factory.config

## Class PropertiesFactoryBean

- java.lang.Object
- - org.springframework.core.io.support.PropertiesLoaderSupport
  - - org.springframework.beans.factory.config.PropertiesFactoryBean

- All Implemented Interfaces:
    FactoryBean<Properties>, InitializingBean

      public class PropertiesFactoryBean
      extends PropertiesLoaderSupport
      implements FactoryBean<Properties>, InitializingBean

  Allows for making a properties file from a classpath location available as Properties instance in a bean factory. Can be used to populate any bean property of type Properties via a bean reference.

  Supports loading from a properties file and/or setting local properties on this FactoryBean. The created Properties instance will be merged from loaded and local values. If neither a location nor local properties are set, an exception will be thrown on initialization.

  Can create a singleton or a new object on each request. Default is a singleton.

  Author:
    Juergen Hoeller
  See Also:
    `PropertiesLoaderSupport.setLocation(org.springframework.core.io.Resource)`, `PropertiesLoaderSupport.setProperties(java.util.Properties)`, `PropertiesLoaderSupport.setLocalOverride(boolean)`, `Properties`

- - ### Field Summary

    - ### Fields inherited from class org.springframework.core.io.support.PropertiesLoaderSupport

      `localOverride, localProperties, logger`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `PropertiesFactoryBean()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `afterPropertiesSet()` Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
    `protected Object` | `createInstance()` Deprecated. as of Spring 3.0, in favor of `createProperties()`
    `protected Properties` | `createProperties()` Template method that subclasses may override to construct the object returned by this factory.
    `Properties` | `getObject()` Return an instance (possibly shared or independent) of the object managed by this factory.
    `Class<Properties>` | `getObjectType()` Return the type of object that this FactoryBean creates, or `null` if not known in advance.
    `boolean` | `isSingleton()` 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)?
    `void` | `setSingleton(boolean singleton)` Set whether a shared 'singleton' Properties instance should be created, or rather a new Properties instance on each request.

    - ### Methods inherited from class org.springframework.core.io.support.PropertiesLoaderSupport

      `loadProperties, mergeProperties, setFileEncoding, setIgnoreResourceNotFound, setLocalOverride, setLocation, setLocations, setProperties, setPropertiesArray, setPropertiesPersister`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### PropertiesFactoryBean

          public PropertiesFactoryBean()

  - ### Method Detail

    - #### setSingleton

          public final void setSingleton(boolean singleton)

      Set whether a shared 'singleton' Properties instance should be created, or rather a new Properties instance on each request.

      Default is "true" (a shared singleton).

    - #### isSingleton

          public final 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<Properties>`
      Returns:
        whether the exposed object is a singleton
      See Also:
        `FactoryBean.getObject()`, `SmartFactoryBean.isPrototype()`

    - #### afterPropertiesSet

          public final void afterPropertiesSet()
                                        throws IOException

      Description copied from interface: `InitializingBean`
      Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).

      This method allows the bean instance to perform initialization only possible when all bean properties have been set and to throw an exception in the event of misconfiguration.

      Specified by:
        `afterPropertiesSet` in interface `InitializingBean`
      Throws:
        `IOException`

    - #### getObject

          public final Properties getObject()
                                     throws IOException

      Description copied from interface: `FactoryBean`
      Return an instance (possibly shared or independent) of the object managed by this factory.

      As with a `BeanFactory`, this allows support for both the Singleton and Prototype design pattern.

      If this FactoryBean is not fully initialized yet at the time of the call (for example because it is involved in a circular reference), throw a corresponding `FactoryBeanNotInitializedException`.

      As of Spring 2.0, FactoryBeans are allowed to return `null` objects. The factory will consider this as normal value to be used; it will not throw a FactoryBeanNotInitializedException in this case anymore. FactoryBean implementations are encouraged to throw FactoryBeanNotInitializedException themselves now, as appropriate.

      Specified by:
        `getObject` in interface `FactoryBean<Properties>`
      Returns:
        an instance of the bean (can be `null`)
      Throws:
        `IOException`
      See Also:
        `FactoryBeanNotInitializedException`

    - #### getObjectType

          public Class<Properties> getObjectType()

      Description copied from interface: `FactoryBean`
      Return the type of object that this FactoryBean creates, or `null` if not known in advance.

      This allows one to check for specific types of beans without instantiating objects, for example on autowiring.

      In the case of implementations that are creating a singleton object, this method should try to avoid singleton creation as far as possible; it should rather estimate the type in advance. For prototypes, returning a meaningful type here is advisable too.

      This method can be called before this FactoryBean has been fully initialized. It must not rely on state created during initialization; of course, it can still use such state if available.

      NOTE: Autowiring will simply ignore FactoryBeans that return `null` here. Therefore it is highly recommended to implement this method properly, using the current state of the FactoryBean.

      Specified by:
        `getObjectType` in interface `FactoryBean<Properties>`
      Returns:
        the type of object that this FactoryBean creates, or `null` if not known at the time of the call
      See Also:
        `ListableBeanFactory.getBeansOfType(java.lang.Class<T>)`

    - #### createProperties

          protected Properties createProperties()
                                         throws IOException

      Template method that subclasses may override to construct the object returned by this factory. The default implementation returns the plain merged Properties instance.

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

      Returns:
        the object returned by this factory
      Throws:
        `IOException` - if an exception occured during properties loading
      See Also:
        `PropertiesLoaderSupport.mergeProperties()`

    - #### createInstance

          @Deprecated
          protected Object createInstance()
                                   throws IOException

      Deprecated. as of Spring 3.0, in favor of `createProperties()`
      Template method that subclasses may override to construct the object returned by this factory. The default implementation returns the plain merged Properties instance.

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

      Returns:
        the object returned by this factory
      Throws:
        `IOException` - if an exception occured during properties loading