org.springframework.beans.factory.annotation: public class: RequiredAnnotationBeanPostProcessor

org.springframework.beans.factory.annotation
public class: RequiredAnnotationBeanPostProcessor [javadoc | source]

java.lang.Object
   org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter
      org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor

All Implemented Interfaces:
PriorityOrdered, SmartInstantiationAwareBeanPostProcessor

org.springframework.beans.factory.config.BeanPostProcessor implementation that enforces required JavaBean properties to have been configured. Required bean properties are detected through a Java 5 annotation: by default, Spring's Required annotation.

The motivation for the existence of this BeanPostProcessor is to allow developers to annotate the setter properties of their own classes with an arbitrary JDK 1.5 annotation to indicate that the container must check for the configuration of a dependency injected value. This neatly pushes responsibility for such checking onto the container (where it arguably belongs), and obviates the need (in part) for a developer to code a method that simply checks that all required properties have actually been set.

Please note that an 'init' method may still need to implemented (and may still be desirable), because all that this class does is enforce that a 'required' property has actually been configured with a value. It does not check anything else... In particular, it does not check that a configured value is not null.

Note: A default RequiredAnnotationBeanPostProcessor will be registered by the "context:annotation-config" and "context:component-scan" XML tags. Remove or turn off the default annotation configuration there if you intend to specify a custom RequiredAnnotationBeanPostProcessor bean definition.

Also see:

setRequiredAnnotationType

Required

author: Rob - Harrop

author: Juergen - Hoeller

since: 2.0 -

Method from org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor Summary:
getOrder, getRequiredAnnotationType, isRequiredProperty, postProcessPropertyValues, setOrder, setRequiredAnnotationType

Methods from org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter:
determineCandidateConstructors, getEarlyBeanReference, postProcessAfterInitialization, postProcessAfterInstantiation, postProcessBeforeInitialization, postProcessBeforeInstantiation, postProcessPropertyValues, predictBeanType

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor Detail:
public int getOrder() { return this.order; }
protected Class getRequiredAnnotationType() { return this.requiredAnnotationType; } Return the 'required' annotation type.
protected boolean isRequiredProperty(PropertyDescriptor propertyDescriptor) { Method setter = propertyDescriptor.getWriteMethod(); return (setter != null && AnnotationUtils.getAnnotation(setter, getRequiredAnnotationType()) != null); } Is the supplied property required to have a value (that is, to be dependency-injected)? This implementation looks for the existence of a "required" annotation on the supplied property .
public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException { if (!this.validatedBeanNames.contains(beanName)) { List< String > invalidProperties = new ArrayList< String >(); for (PropertyDescriptor pd : pds) { if (isRequiredProperty(pd) && !pvs.contains(pd.getName())) { invalidProperties.add(pd.getName()); } } if (!invalidProperties.isEmpty()) { throw new BeanInitializationException(buildExceptionMessage(invalidProperties, beanName)); } this.validatedBeanNames.add(beanName); } return pvs; }
public void setOrder(int order) { this.order = order; }
public void setRequiredAnnotationType(Class requiredAnnotationType) { Assert.notNull(requiredAnnotationType, "'requiredAnnotationType' must not be null"); this.requiredAnnotationType = requiredAnnotationType; } Set the 'required' annotation type, to be used on bean property setter methods. The default required annotation type is the Spring-provided Required annotation. This setter property exists so that developers can provide their own (non-Spring-specific) annotation type to indicate that a property value is required.