org.springframework.aop.interceptor

Class ExposeInvocationInterceptor

java.lang.Object

org.springframework.aop.interceptor.ExposeInvocationInterceptor

All Implemented Interfaces:

Serializable, Advice, Interceptor, MethodInterceptor, Ordered, PriorityOrdered

public final class ExposeInvocationInterceptor
extends Object
implements MethodInterceptor, PriorityOrdered, Serializable

Interceptor that exposes the current MethodInvocation as a thread-local object. We occasionally need to do this; for example, when a pointcut (e.g. an AspectJ expression pointcut) needs to know the full invocation context.

Don't use this interceptor unless this is really necessary. Target objects should not normally know about Spring AOP, as this creates a dependency on Spring API. Target objects should be plain POJOs as far as possible.

If used, this interceptor will normally be the first in the interceptor chain.

Author:

Rod Johnson, Juergen Hoeller

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static Advisor	ADVISOR Singleton advisor for this class.
static ExposeInvocationInterceptor	INSTANCE Singleton instance of this class.

Fields inherited from interface org.springframework.core.Ordered

HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE

Method Summary

Modifier and Type	Method and Description
static MethodInvocation	currentInvocation() Return the AOP Alliance MethodInvocation object associated with the current invocation.
int	getOrder() Get the order value of this object.
Object	invoke(MethodInvocation mi) Implement this method to perform extra treatments before and after the invocation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final ExposeInvocationInterceptor INSTANCE

Singleton instance of this class.

ADVISOR

public static final Advisor ADVISOR

Singleton advisor for this class. Use in preference to INSTANCE when using Spring AOP, as it prevents the need to create a new Advisor to wrap the instance.

Method Detail

currentInvocation

public static MethodInvocation currentInvocation()
                                          throws IllegalStateException

Return the AOP Alliance MethodInvocation object associated with the current invocation.

Returns:

the invocation object associated with the current invocation

Throws:

IllegalStateException - if there is no AOP invocation in progress, or if the ExposeInvocationInterceptor was not added to this interceptor chain

invoke

@Nullable
public Object invoke(MethodInvocation mi)
                        throws Throwable

Description copied from interface: MethodInterceptor

Implement this method to perform extra treatments before and after the invocation. Polite implementations would certainly like to invoke Joinpoint.proceed().

Specified by:

invoke in interface MethodInterceptor

Parameters:

mi - the method invocation joinpoint

Returns:

the result of the call to Joinpoint.proceed(); might be intercepted by the interceptor

Throws:

Throwable - if the interceptors or the target object throws an exception

getOrder

public int getOrder()

Description copied from interface: Ordered

Get the order value of this object.

Higher values are interpreted as lower priority. As a consequence, the object with the lowest value has the highest priority (somewhat analogous to Servlet load-on-startup values).

Same order values will result in arbitrary sort positions for the affected objects.

Specified by:

getOrder in interface Ordered

Returns:

the order value

See Also:

Ordered.HIGHEST_PRECEDENCE, Ordered.LOWEST_PRECEDENCE