Spring Beans 6.1.4 · org.springframework.beans.factory.config.MethodInvokingFactoryBean

FactoryBean which returns a value which is the result of a static or instance method invocation. For most use cases it is better to just use the container's built-in factory method support for the same purpose, since that is smarter at converting arguments. This factory bean is still useful though when you need to call a method which doesn't return any value (for example, a static class method to force some sort of initialization to happen). This use case is not supported by factory methods, since a return value is needed to obtain the bean instance.

Note that as it is expected to be used mostly for accessing factory methods, this factory by default operates in a singleton fashion. The first request to getObject by the owning bean factory will cause a method invocation, whose return value will be cached for subsequent requests. An internal singleton property may be set to "false", to cause this factory to invoke the target method each time it is asked for an object.

Note

If your target method does not produce a result to expose, consider MethodInvokingBean instead, which avoids the type determination and lifecycle limitations that this MethodInvokingFactoryBean comes with.

This invoker supports any kind of target method. A static method may be specified by setting the targetMethod property to a String representing the static method name, with targetClass specifying the Class that the static method is defined on. Alternatively, a target instance method may be specified, by setting the targetObject property as the target object, and the targetMethod property as the name of the method to call on that target object. Arguments for the method invocation may be specified by setting the arguments property.

This class depends on afterPropertiesSet() being called once all properties have been set, as per the InitializingBean contract.

An example (in an XML based bean factory definition) of a bean definition which uses this class to call a static factory method:

<bean id="myObject" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
  <property name="staticMethod" value="com.whatever.MyClassFactory.getInstance"/>
</bean>

An example of calling a static method then an instance method to get at a Java system property. Somewhat verbose, but it works.

<bean id="sysProps" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
  <property name="targetClass" value="java.lang.System"/>
  <property name="targetMethod" value="getProperties"/>
</bean>

<bean id="javaVersion" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
  <property name="targetObject" ref="sysProps"/>
  <property name="targetMethod" value="getProperty"/>
  <property name="arguments" value="java.version"/>
</bean>

Modifier and Type	Field and Description
private boolean	initialized
private boolean	singleton
private Object	singletonObject Method call result in the singleton case.

Constructor Summary

Access	Constructor and Description
public	MethodInvokingFactoryBean()

Method Summary

Modifier and Type	Method and Description
public void	afterPropertiesSet() Overrides org.springframework.beans.factory.config.MethodInvokingBean.afterPropertiesSet. Implements org.springframework.beans.factory.InitializingBean.afterPropertiesSet. 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.
public Object	getObject() Implements org.springframework.beans.factory.FactoryBean.getObject. Returns the same value each time if the singleton property is set to "true", otherwise returns the value returned from invoking the specified method on the fly.
public Class<?>	getObjectType() Implements org.springframework.beans.factory.FactoryBean.getObjectType. Return the type of object that this FactoryBean creates, or `null` if not known in advance.
public boolean	isSingleton() Overrides default org.springframework.beans.factory.FactoryBean.isSingleton. Is the object managed by this factory a singleton?
public void	setSingleton(boolean singleton) Set if a singleton should be created, or a new object on each `getObject()` request otherwise.

Inherited from org.springframework.beans.factory.config.MethodInvokingBean:: getDefaultTypeConverter invokeWithTargetException resolveClassName setBeanClassLoader setBeanFactory

Field Detail

initialized	back to summary
private boolean initialized

singleton	back to summary
private boolean singleton

singletonObject	back to summary
private Object singletonObject Method call result in the singleton case. Annotations @Nullable

Constructor Detail

MethodInvokingFactoryBean	back to summary
public MethodInvokingFactoryBean()

Method Detail

afterPropertiesSet back to summary

afterPropertiesSet	back to summary
public void afterPropertiesSet() throws Exception Overrides org.springframework.beans.factory.config.MethodInvokingBean.afterPropertiesSet. Implements org.springframework.beans.factory.InitializingBean.afterPropertiesSet. Doc from org.springframework.beans.factory.InitializingBean.afterPropertiesSet. 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. Annotations @Override Exceptions Exception: in the event of misconfiguration (such as failure to set an essential property) or if initialization fails for any other reason

public void afterPropertiesSet() throws Exception

Overrides org.springframework.beans.factory.config.MethodInvokingBean.afterPropertiesSet.

Implements org.springframework.beans.factory.InitializingBean.afterPropertiesSet.

Doc from org.springframework.beans.factory.InitializingBean.afterPropertiesSet.

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.

Annotations

@Override

Exceptions

Exception:: in the event of misconfiguration (such as failure to set an essential property) or if initialization fails for any other reason

getObject back to summary

getObject	back to summary
public Object getObject() throws Exception Implements org.springframework.beans.factory.FactoryBean.getObject. Returns the same value each time if the singleton property is set to "true", otherwise returns the value returned from invoking the specified method on the fly. Returns:Object Doc from org.springframework.beans.factory.FactoryBean.getObject. an instance of the bean (can be `null`) Annotations @Override @Nullable Exceptions Exception: Doc from org.springframework.beans.factory.FactoryBean.getObject. in case of creation errors

public Object getObject() throws Exception

Implements org.springframework.beans.factory.FactoryBean.getObject.

Returns the same value each time if the singleton property is set to "true", otherwise returns the value returned from invoking the specified method on the fly.

Returns:Object

Doc from org.springframework.beans.factory.FactoryBean.getObject.

an instance of the bean (can be null)

Annotations

@Override
@Nullable

Exceptions

Exception:

Doc from org.springframework.beans.factory.FactoryBean.getObject.

in case of creation errors

getObjectType back to summary

getObjectType	back to summary
public Class<?> getObjectType() Implements org.springframework.beans.factory.FactoryBean.getObjectType. Return the type of object that this FactoryBean creates, or `null` if not known in advance. Returns:Class<?> Doc from org.springframework.beans.factory.FactoryBean.getObjectType. the type of object that this FactoryBean creates, or `null` if not known at the time of the call Annotations @Override

public Class<?> getObjectType()

Implements org.springframework.beans.factory.FactoryBean.getObjectType.

Return the type of object that this FactoryBean creates, or null if not known in advance.

Returns:Class<?>

Doc from org.springframework.beans.factory.FactoryBean.getObjectType.

the type of object that this FactoryBean creates, or null if not known at the time of the call

Annotations

@Override

isSingleton back to summary

isSingleton	back to summary
public boolean isSingleton() Overrides default org.springframework.beans.factory.FactoryBean.isSingleton. Doc from org.springframework.beans.factory.FactoryBean.isSingleton. Is the object managed by this factory a singleton? That is, will `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. Returns:boolean whether the exposed object is a singleton Annotations @Override

public boolean isSingleton()

Overrides default org.springframework.beans.factory.FactoryBean.isSingleton.

Doc from org.springframework.beans.factory.FactoryBean.isSingleton.

Is the object managed by this factory a singleton? That is, will 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.

Returns:boolean

whether the exposed object is a singleton

Annotations

@Override

setSingleton	back to summary
public void setSingleton(boolean singleton) Set if a singleton should be created, or a new object on each `getObject()` request otherwise. Default is "true".

public Class MethodInvokingFactoryBean

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail