001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.rest.stats;
018
019import static org.apache.juneau.commons.utils.ThrowableUtils.*;
020
021import java.lang.reflect.*;
022
023import org.apache.juneau.commons.reflect.*;
024import org.apache.juneau.cp.*;
025
026/**
027 * A wrapper around a {@link Method#invoke(Object, Object...)} method that allows for basic instrumentation.
028 */
029public class MethodInvoker {
030   private final MethodInfo m;
031   private final MethodExecStats stats;
032
033   /**
034    * Constructor.
035    *
036    * @param m The method being wrapped.
037    * @param stats The instrumentor.
038    */
039   public MethodInvoker(Method m, MethodExecStats stats) {
040      this.m = MethodInfo.of(m);
041      this.stats = stats;
042   }
043
044   /**
045    * Convenience method for calling <c>inner().getDeclaringClass()</c>
046    *
047    * @return The declaring class of the method.
048    */
049   public ClassInfo getDeclaringClass() { return m.getDeclaringClass(); }
050
051   /**
052    * Convenience method for calling <c>inner().getName()</c>
053    *
054    * @return The name of the method.
055    */
056   public String getFullName() { return m.getFullName(); }
057
058   /**
059    * Returns the stats of this method invoker.
060    *
061    * @return The stats of this method invoker.
062    */
063   public MethodExecStats getStats() { return stats; }
064
065   /**
066    * Returns the inner method.
067    *
068    * @return The inner method.
069    */
070   public MethodInfo inner() {
071      return m;
072   }
073
074   /**
075    * Invokes the wrapped method using parameters from the specified bean store.
076    *
077    * @param beanStore The bean store to use to resolve parameters.
078    * @param o The object to invoke the method on.
079    * @return The result of invoking the method.
080    * @throws IllegalAccessException If method cannot be accessed.
081    * @throws IllegalArgumentException If wrong arguments were passed to method.
082    * @throws InvocationTargetException If method threw an exception.
083    */
084   public Object invoke(BeanStore beanStore, Object o) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
085      if (beanStore.hasAllParams(m))
086         return invoke(o, beanStore.getParams(m));
087      throw illegalArg("Could not find prerequisites to invoke method ''{0}'': {1}", getFullName(), beanStore.getMissingParams(m));
088   }
089
090   /**
091    * Invokes the underlying method.
092    *
093    * @param o  The object the underlying method is invoked from.
094    * @param args  The arguments used for the method call.
095    * @return  The result of dispatching the method represented by this object on {@code obj} with parameters {@code args}
096    * @throws IllegalAccessException If method cannot be accessed.
097    * @throws IllegalArgumentException If wrong arguments were passed to method.
098    * @throws InvocationTargetException If method threw an exception.
099    */
100   public Object invoke(Object o, Object...args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
101      long startTime = System.nanoTime();
102      stats.started();
103      try {
104         return m.inner().invoke(o, args);
105      } catch (IllegalAccessException | IllegalArgumentException e) {
106         stats.error(e);
107         throw e;
108      } catch (InvocationTargetException e) {
109         stats.error(e.getTargetException());
110         throw e;
111      } finally {
112         stats.finished(System.nanoTime() - startTime);
113      }
114   }
115}