/*

  * Copyright 2005-2007 The Kuali Foundation

  * 

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  * 

  * 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.kuali.rice.krad.util.spring;

 import java.lang.reflect.Method;

 import org.aopalliance.intercept.MethodInterceptor;

 import org.aopalliance.intercept.MethodInvocation;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * This interceptor generates log message before entering and after leaving the method being intercepted.

  * 

  * 

  */

 public class MethodLoggingInterceptor implements MethodInterceptor {

     private static final Log LOG = LogFactory.getLog(MethodLoggingInterceptor.class);

     /**

      * Surrounds the method invocation with FATAL-level log messages. Using FATAL because I want to make sure that the log messages

      * will always show up, since the correct way to deactivate method-level logging is to remove (or comment) the bean name from

      * the KualiTestSpringLogging.xml file.

      * 

      * @see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation)

      */

     public Object invoke(MethodInvocation invocation) throws Throwable {

         long startTime = System.currentTimeMillis();

         Object methodResult = null;

         String invocationLabel = buildInvocationLabel(invocation);

         try {

             LOG.fatal("entering " + invocationLabel);

             methodResult = invocation.proceed();

         }

         catch (Exception invocationException) {

             String exceptionLabel = buildExceptionLabel(invocationException);

             LOG.fatal("aborting " + invocationLabel + ": throwing " + exceptionLabel);

             throw invocationException;

         }

         LOG.fatal(new StringBuffer("leaving  ").append(invocationLabel).append(" / took ").append(System.currentTimeMillis() - startTime).append(" ms"));

         return methodResult;

     }

     /**

      * @param invocation MethodInvocation being labeled

      * @return String used to identify this MethodInvocation

      */

     private String buildInvocationLabel(MethodInvocation invocation) {

         StringBuffer invocationLabel = new StringBuffer();

         Method method = invocation.getMethod();

         Class targetClass = invocation.getThis().getClass();

         Class declaringClass = method.getDeclaringClass();

         // {targetClass} declaringClass.method

         if (targetClass != declaringClass) {

             invocationLabel.append("{");

             invocationLabel.append(declaringClass.getName());

             invocationLabel.append("} ");

         }

         invocationLabel.append(targetClass.getName() + "." + method.getName());

         // (paramClass=argValue[,paramClass=argValue...])

         Class[] paramTypes = method.getParameterTypes();

         Object[] argValues = invocation.getArguments();

         invocationLabel.append("(");

         if (paramTypes != null) {

             for (int i = 0; i < paramTypes.length; i++) {

                 if (i > 0) {

                     invocationLabel.append(",");

                 }

                 invocationLabel.append(paramTypes[i].getName());

                 invocationLabel.append("=");

                 // differentiate between literal null and object whose toString returns null

                 if (argValues[i] == null) {

                     invocationLabel.append("<literal null>");

                 }

                 else {

                     invocationLabel.append(argValues[i]);

                 }

             }

         }

         invocationLabel.append(")");

         return invocationLabel.toString();

     }

     /**

      * @param e Exception being labeled

      * @return String used to identify this Exception

      */

     private String buildExceptionLabel(Exception e) {

         String className = e.getClass().getName();

         String exceptionLabel = StringUtils.substringAfterLast(className, ".");

         if (StringUtils.isBlank(exceptionLabel)) {

             exceptionLabel = className;

         }

         return exceptionLabel;

     }

 }