/*
    * Copyright 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 net.sf.sensor.support.spring;
  
  import java.util.Iterator;
  import java.util.Set;
  
  import org.aopalliance.intercept.MethodInterceptor;
  import org.aopalliance.intercept.MethodInvocation;
  
  import org.springframework.util.ClassUtils;
  import org.springframework.util.StringUtils;
  
  import net.sf.sensor.timer.Timer;
  import net.sf.sensor.timer.TimerRuntime;
  
  /***
   * Spring method interceptor that wraps a method call in a Sensor Timer
   * using the dependency injected {@link TimerRuntime}.
   * <p>
   * Method signature util methods copied from the extended JamonIntercepter
   * as blogged by Gerald Loeffler.
   * 
   * @author Age Mooy 
   */
  public class MethodTimingInterceptor implements MethodInterceptor {
  
    /*** The {@link TimerRuntime} we use to access timers. */
    private TimerRuntime timerRuntime = null;
    
    /*** The set of labels to associate with the {@link Timer Timers}. */
    private Set associatedLabels = null;
    
    /***
     * Property that controls whether the generated {@link Timer} label
     * will contain the method parameter types or not. Defaults to true.
     */
    private boolean useParamTypesInId = true;
    
    
    // ==========================================================================
    // Interface implementation
    // ==========================================================================
    
    /***
     * Wraps the intercepted method call in a Timer using the method signature
     * as the Timer label. If there is no {@link TimerRuntime} available, this
     * method proceeds with the intercepted method without doing anything else.
     * 
     * @see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation)
     */
    public Object invoke(MethodInvocation mi) throws Throwable {
      Timer timer = null;
      
      if (timerRuntime != null) {
        timer = timerRuntime.getTimer(methodSignature(mi));
        
        if (associatedLabels != null) {
          for (Iterator i = associatedLabels.iterator(); i.hasNext();) {
            Object label = i.next();
            
            if (label instanceof String) {
              timer.addLabel((String) label);
            }
          }
        }
        
        timer.start();
      }
      
      try {
        return mi.proceed();
      } finally {
        if (timerRuntime != null) {
          timer.stop();
        }      
      }
    }
    
    
    // ==========================================================================
    // Dependency Injection
    // ==========================================================================
    
    /***
    * Sets the timerRuntime.
    * @param timerRuntime The timerRuntime to set.
    */
   public void setTimerRuntime(TimerRuntime timerRuntime) {
     this.timerRuntime = timerRuntime;
   }
   
   /***
    * Sets the associatedLabels.
    * @param associatedLabels The associatedLabels to set.
    */
   public void setAssociatedLabels(Set associatedLabels) {
     this.associatedLabels = associatedLabels;
   }
   
   /***
    * Sets the property that controls whether the generated {@link Timer}
    * label will contain the method parameter types or not. Defaults to true.
    * @param useParamTypesInId The useParamTypesInId to set.
    */
   public void setUseParamTypesInId(boolean useParamTypesInId) {
     this.useParamTypesInId = useParamTypesInId;
   }
   
   
   // ==========================================================================
   // Private utils
   // ==========================================================================
   
   /***
    * Private util method to create a simple String representation of an
    * intercepted MethodInvocation instance.
    * @param mi the intercepted MethodInvocation instance.
    * @return a String representation of the specified MethodInvocation instance.
    */
   private String methodSignature(MethodInvocation mi) {
     StringBuffer methodSignature = new StringBuffer(ClassUtils.getQualifiedMethodName(mi.getMethod()));
     Class[]      paramTypes      = mi.getMethod().getParameterTypes();
     
     methodSignature.append("(");
     
     if (useParamTypesInId) {
       for (int i = 0; i < paramTypes.length; i++) {
         if (i > 0) {
           methodSignature.append(",");
         }
 
         methodSignature.append(getShortName(paramTypes[i]));
       }
     }
     
     methodSignature.append(")");
     
     return methodSignature.toString();
   }
 
   /***
    * Util method to get the short name for the specified class.
    * 
    * @param clazz The class instance to use.
    * @return the class name without its package name.
    */
   private String getShortName(Class clazz) {
     String  name = clazz.getName();
     Package pack = clazz.getPackage();
     
     if (pack != null) {
       name = StringUtils.delete(name, pack.getName() + ".");
     }
     
     return name;
   }
   
 }