/*
 * Copyright 2002-2018 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.aopalliance.intercept;

import org.aopalliance.aop.Advice;

This interface represents a generic interceptor.

A generic interceptor can intercept runtime events that occur within a base program. Those events are materialized by (reified in) joinpoints. Runtime joinpoints can be invocations, field access, exceptions...

This interface is not used directly. Use the sub-interfaces to intercept specific events. For instance, the following class implements some specific interceptors in order to implement a debugger:

class DebuggingInterceptor implements MethodInterceptor,
    ConstructorInterceptor, FieldInterceptor {
  Object invoke(MethodInvocation i) throws Throwable {
    debug(i.getMethod(), i.getThis(), i.getArgs());
    return i.proceed();
  }
  Object construct(ConstructorInvocation i) throws Throwable {
    debug(i.getConstructor(), i.getThis(), i.getArgs());
    return i.proceed();
  }
  Object get(FieldAccess fa) throws Throwable {
    debug(fa.getField(), fa.getThis(), null);
    return fa.proceed();
  }
  Object set(FieldAccess fa) throws Throwable {
    debug(fa.getField(), fa.getThis(), fa.getValueToSet());
    return fa.proceed();
  }
  void debug(AccessibleObject ao, Object this, Object value) {
    ...
  }
}
Author:Rod Johnson
See Also:
/** * This interface represents a generic interceptor. * * <p>A generic interceptor can intercept runtime events that occur * within a base program. Those events are materialized by (reified * in) joinpoints. Runtime joinpoints can be invocations, field * access, exceptions... * * <p>This interface is not used directly. Use the sub-interfaces * to intercept specific events. For instance, the following class * implements some specific interceptors in order to implement a * debugger: * * <pre class=code> * class DebuggingInterceptor implements MethodInterceptor, * ConstructorInterceptor, FieldInterceptor { * * Object invoke(MethodInvocation i) throws Throwable { * debug(i.getMethod(), i.getThis(), i.getArgs()); * return i.proceed(); * } * * Object construct(ConstructorInvocation i) throws Throwable { * debug(i.getConstructor(), i.getThis(), i.getArgs()); * return i.proceed(); * } * * Object get(FieldAccess fa) throws Throwable { * debug(fa.getField(), fa.getThis(), null); * return fa.proceed(); * } * * Object set(FieldAccess fa) throws Throwable { * debug(fa.getField(), fa.getThis(), fa.getValueToSet()); * return fa.proceed(); * } * * void debug(AccessibleObject ao, Object this, Object value) { * ... * } * } * </pre> * * @author Rod Johnson * @see Joinpoint */
public interface Interceptor extends Advice { }