org.springframework.aop.interceptor
Class ExposeInvocationInterceptor

java.lang.Object
  org.springframework.aop.interceptor.ExposeInvocationInterceptor

All Implemented Interfaces:

java.io.Serializable, Ordered

public class ExposeInvocationInterceptor
extends java.lang.Object
implements Ordered, java.io.Serializable

Interceptor that exposes the current org.aopalliance.intercept.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

static Advisor	ADVISOR Singleton advisor for this class.
static ExposeInvocationInterceptor	INSTANCE Singleton instance of this class
private static java.lang.ThreadLocal<MethodInvocation>	invocation

Fields inherited from interface org.springframework.core.Ordered

HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE

Constructor Summary

private

ExposeInvocationInterceptor() Ensures that only the canonical instance can be created.

Method Summary

static MethodInvocation	currentInvocation() Return the AOP Alliance MethodInvocation object associated with the current invocation.
int	getOrder() Return the order value of this object, with a higher value meaning greater in terms of sorting.
java.lang.Object	invoke(MethodInvocation mi)
private java.lang.Object	readResolve() Required to support serialization.

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.

invocation

private static final java.lang.ThreadLocal<MethodInvocation> invocation

Constructor Detail

ExposeInvocationInterceptor

private ExposeInvocationInterceptor()

Ensures that only the canonical instance can be created.

Method Detail

currentInvocation

public static MethodInvocation currentInvocation()
                                          throws java.lang.IllegalStateException

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

Returns:

the invocation object associated with the current invocation

Throws:

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

invoke

public java.lang.Object invoke(MethodInvocation mi)
                        throws java.lang.Throwable

Throws:

java.lang.Throwable

getOrder

public int getOrder()

Description copied from interface: Ordered

Return the order value of this object, with a higher value meaning greater in terms of sorting.

Normally starting with 0, with Integer.MAX_VALUE indicating the greatest value. Same order values will result in arbitrary positions for the affected objects.

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

Specified by:

getOrder in interface Ordered

Returns:

the order value

readResolve

private java.lang.Object readResolve()

Required to support serialization. Replaces with canonical instance on deserialization, protecting Singleton pattern.

Alternative to overriding the equals method.