Package org.springframework.beans.factory.config

Class YamlMapFactoryBean

java.lang.Object
org.springframework.beans.factory.config.YamlProcessor
org.springframework.beans.factory.config.YamlMapFactoryBean
All Implemented Interfaces:
FactoryBean<Map<String,Object>>, InitializingBean
public class YamlMapFactoryBean extends YamlProcessor implements FactoryBean<Map<String,Object>>, InitializingBean
Factory for a Map that reads from a YAML source, preserving the YAML-declared value types and their structure.

YAML is a nice human-readable format for configuration, and it has some useful hierarchical properties. It's more or less a superset of JSON, so it has a lot of similar features.

If multiple resources are provided the later ones will override entries in the earlier ones hierarchically; that is, all entries with the same nested key of type Map at any depth are merged. For example: 

 foo:
   bar:
    one: two
 three: four
plus (later in the list) 
 foo:
   bar:
    one: 2
 five: six
results in an effective input of 
 foo:
   bar:
    one: 2
 three: four
 five: six
Note that the value of "foo" in the first document is not simply replaced with the value in the second, but its nested values are merged.

Requires SnakeYAML 1.18 or higher, as of Spring Framework 5.0.6.

Since:
4.1
Author:
Dave Syer, Juergen Hoeller

  • Constructor Details

    • YamlMapFactoryBean

      public YamlMapFactoryBean()

  • Method Details

    • 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.

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

      Specified by:
      isSingleton in interface FactoryBean<Map<String,Object>>
      Returns:
      whether the exposed object is a singleton
      See Also:

    • afterPropertiesSet

      public void afterPropertiesSet()
      Description copied from interface: InitializingBean
      Invoked by the containing BeanFactory after it has set all bean properties and satisfied BeanFactoryAware, ApplicationContextAware etc.

      This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.

      Specified by:
      afterPropertiesSet in interface InitializingBean

    • getObject

      @Nullable public Map<String,Object> getObject()
      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<Map<String,Object>>
      Returns:
      an instance of the bean (can be null)
      See Also:

    • getObjectType

      public Class<?> 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<Map<String,Object>>
      Returns:
      the type of object that this FactoryBean creates, or null if not known at the time of the call
      See Also:

    • createMap

      protected Map<String,Object> createMap()
      Template method that subclasses may override to construct the object returned by this factory.

      Invoked lazily the first time getObject() is invoked in case of a shared singleton; else, on each getObject() call.

      The default implementation returns the merged Map instance.

      Returns:
      the object returned by this factory
      See Also: