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java.lang.Objectorg.springframework.util.MethodInvoker
org.springframework.beans.support.ArgumentConvertingMethodInvoker
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 become the bean.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.
A static target 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 args 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</value></property> </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</value></property> <property name="targetMethod"><value>getProperties</value></property> </bean> <bean id="javaVersion" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"> <property name="targetObject"><ref local='sysProps'/></property> <property name="targetMethod"><value>getProperty</value></property> <property name="arguments"> <list> <value>java.version</value> </list> </property> </bean>
Nested Class Summary |
Nested classes inherited from class org.springframework.util.MethodInvoker |
MethodInvoker.VoidType |
Field Summary |
Fields inherited from class org.springframework.util.MethodInvoker |
VOID |
Constructor Summary | |
MethodInvokingFactoryBean()
|
Method Summary | |
void |
afterPropertiesSet()
Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware). |
Object |
getObject()
Will return the same value each time if the singleton property is set to true, and otherwise return the value returned from invoking the specified method. |
Class |
getObjectType()
Return the type of object that this FactoryBean creates, or null if not known in advance. |
boolean |
isSingleton()
Is the bean managed by this factory a singleton or a prototype? |
void |
setSingleton(boolean singleton)
Set if a singleton should be created, or a new object on each request else. |
Methods inherited from class org.springframework.beans.support.ArgumentConvertingMethodInvoker |
prepare, registerCustomEditor |
Methods inherited from class org.springframework.util.MethodInvoker |
getArguments, getPreparedMethod, getTargetClass, getTargetMethod, getTargetObject, invoke, setArguments, setStaticMethod, setTargetClass, setTargetMethod, setTargetObject |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public MethodInvokingFactoryBean()
Method Detail |
public void setSingleton(boolean singleton)
public void afterPropertiesSet() throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException
InitializingBean
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.
afterPropertiesSet
in interface InitializingBean
ClassNotFoundException
NoSuchMethodException
InvocationTargetException
IllegalAccessException
public Object getObject() throws InvocationTargetException, IllegalAccessException
getObject
in interface FactoryBean
InvocationTargetException
IllegalAccessException
FactoryBeanNotInitializedException
public Class getObjectType()
FactoryBean
For a singleton, this 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.
getObjectType
in interface FactoryBean
ListableBeanFactory.getBeansOfType(java.lang.Class)
public boolean isSingleton()
FactoryBean
The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.
isSingleton
in interface FactoryBean
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