org.springframework.aop.support: public class: DelegatingIntroductionInterceptor

org.springframework.aop.support
public class: DelegatingIntroductionInterceptor [javadoc | source]

java.lang.Object
   org.springframework.aop.support.IntroductionInfoSupport
      org.springframework.aop.support.DelegatingIntroductionInterceptor

All Implemented Interfaces:
IntroductionInterceptor, Serializable, IntroductionInfo

Direct Known Subclasses:
ExposeBeanNameIntroduction

Convenient implementation of the org.springframework.aop.IntroductionInterceptor interface.

Subclasses merely need to extend this class and implement the interfaces to be introduced themselves. In this case the delegate is the subclass instance itself. Alternatively a separate delegate may implement the interface, and be set via the delegate bean property.

Delegates or subclasses may implement any number of interfaces. All interfaces except IntroductionInterceptor are picked up from the subclass or delegate by default.

The suppressInterface method can be used to suppress interfaces implemented by the delegate but which should not be introduced to the owning AOP proxy.

An instance of this class is serializable if the delegate is.

Also see:

suppressInterface

DelegatePerTargetObjectIntroductionInterceptor

author: Rod - Johnson

author: Juergen - Hoeller

since: 16.11.2003 -

Fields inherited from org.springframework.aop.support.IntroductionInfoSupport:
logger, publishedInterfaces

Constructor:

Constructor:
protected DelegatingIntroductionInterceptor() { init(this); } Construct a new DelegatingIntroductionInterceptor. The delegate will be the subclass, which must implement additional interfaces.
public DelegatingIntroductionInterceptor(Object delegate) { init(delegate); } Construct a new DelegatingIntroductionInterceptor, providing a delegate that implements the interfaces to be introduced. Parameters: `delegate` - the delegate that implements the introduced interfaces

 protected DelegatingIntroductionInterceptor() {
		init(this);
}

Construct a new DelegatingIntroductionInterceptor. The delegate will be the subclass, which must implement additional interfaces.

 public DelegatingIntroductionInterceptor(Object delegate) {
		init(delegate);
}

Construct a new DelegatingIntroductionInterceptor, providing a delegate that implements the interfaces to be introduced.

Parameters:

delegate - the delegate that implements the introduced interfaces

Method from org.springframework.aop.support.DelegatingIntroductionInterceptor Summary:
doProceed, invoke

Methods from org.springframework.aop.support.IntroductionInfoSupport:
getInterfaces, implementInterfacesOnObject, implementsInterface, isMethodOnIntroducedInterface, suppressInterface

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

Method from org.springframework.aop.support.DelegatingIntroductionInterceptor Detail:
protected Object doProceed(MethodInvocation mi) throws Throwable { // If we get here, just pass the invocation on. return mi.proceed(); } Proceed with the supplied org.aopalliance.intercept.MethodInterceptor . Subclasses can override this method to intercept method invocations on the target object which is useful when an introduction needs to monitor the object that it is introduced into. This method is never called for MethodInvocations on the introduced interfaces.
public Object invoke(MethodInvocation mi) throws Throwable { if (isMethodOnIntroducedInterface(mi)) { // Using the following method rather than direct reflection, we // get correct handling of InvocationTargetException // if the introduced method throws an exception. Object retVal = AopUtils.invokeJoinpointUsingReflection(this.delegate, mi.getMethod(), mi.getArguments()); // Massage return value if possible: if the delegate returned itself, // we really want to return the proxy. if (retVal == this.delegate && mi instanceof ProxyMethodInvocation) { Object proxy = ((ProxyMethodInvocation) mi).getProxy(); if (mi.getMethod().getReturnType().isInstance(proxy)) { retVal = proxy; } } return retVal; } return doProceed(mi); } Subclasses may need to override this if they want to perform custom behaviour in around advice. However, subclasses should invoke this method, which handles introduced interfaces and forwarding to the target.

Method from org.springframework.aop.support.DelegatingIntroductionInterceptor Detail:

 protected Object doProceed(MethodInvocation mi) throws Throwable {
		// If we get here, just pass the invocation on.
		return mi.proceed();
}

org.aopalliance.intercept.MethodInterceptor

never

MethodInvocations

 public Object invoke(MethodInvocation mi) throws Throwable {
		if (isMethodOnIntroducedInterface(mi)) {
			// Using the following method rather than direct reflection, we
			// get correct handling of InvocationTargetException
			// if the introduced method throws an exception.
			Object retVal = AopUtils.invokeJoinpointUsingReflection(this.delegate, mi.getMethod(), mi.getArguments());
			// Massage return value if possible: if the delegate returned itself,
			// we really want to return the proxy.
			if (retVal == this.delegate && mi instanceof ProxyMethodInvocation) {
				Object proxy = ((ProxyMethodInvocation) mi).getProxy();
				if (mi.getMethod().getReturnType().isInstance(proxy)) {
					retVal = proxy;
				}
			}
			return retVal;
		}
		return doProceed(mi);
}

Subclasses may need to override this if they want to perform custom behaviour in around advice. However, subclasses should invoke this method, which handles introduced interfaces and forwarding to the target.