org.springframework.aop.TargetSource Maven / Gradle / Ivy
/*<
* Copyright 2002-2005 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.aop;
/**
* A TargetSource is used to obtain the current "target" of an AOP invocation,
* which will be invoked via reflection if no around advice chooses to end the
* interceptor chain itself.
*
* If a TargetSource is "static", it will always return the same target,
* allowing optimizations in the AOP framework. Dynamic target sources can
* support pooling, hot swapping, etc.
*
*
Application developers don't usually need to work with TargetSources
* directly: This is an AOP framework interface.
*
* @author Rod Johnson
*/
public interface TargetSource {
/**
* Return the type of targets returned by this TargetSource.
* Can return null, although certain usages of a TargetSource
* might just work with a predetermined target class.
*/
Class getTargetClass();
/**
* Will all calls to getTarget() return the same object?
* In that case, there will be no need to invoke releaseTarget,
* and the AOP framework can cache the return value of getTarget().
* @return whether the target is immutable
* @see #getTarget
*/
boolean isStatic();
/**
* Return a target instance. Invoked immediately before the
* AOP framework calls the "target" of an AOP method invocation.
* @return the target object, whicch contains the joinpoint
* @throws Exception if the target object can't be resolved
*/
Object getTarget() throws Exception;
/**
* Release the given target object obtained from the
* getTarget() method.
* @param target object obtained from a call to getTarget()
* @throws Exception if the object can't be released
* @see #getTarget
*/
void releaseTarget(Object target) throws Exception;
}