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     */
017    package org.apache.commons.monitoring.aop;
018    
019    import org.apache.commons.monitoring.configuration.Configuration;
020    import org.apache.commons.monitoring.util.ClassLoaders;
021    import org.apache.commons.proxy.Invoker;
022    import org.apache.commons.proxy.ProxyFactory;
023    
024    import java.lang.reflect.InvocationTargetException;
025    import java.lang.reflect.Method;
026    
027    public final class MonitoringProxyFactory {
028        private static final ProxyFactory PROXY_FACTORY = Configuration.newInstance(ProxyFactory.class);
029    
030        public static <T> T monitor(final Class<T> clazz, final Object instance) {
031            return clazz.cast(PROXY_FACTORY.createInvokerProxy(ClassLoaders.current(), new MonitoringHandler(instance), new Class<?>[]{clazz}));
032        }
033    
034        private MonitoringProxyFactory() {
035            // no-op
036        }
037    
038        private static class MonitoringHandler extends AbstractPerformanceInterceptor<Invocation> implements Invoker {
039            private final Object instance;
040    
041            public MonitoringHandler(final Object instance) {
042                this.instance = instance;
043            }
044    
045            @Override
046            public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
047                return doInvoke(new Invocation(instance, method, args));
048            }
049    
050            @Override
051            protected Object proceed(final Invocation invocation) throws Throwable {
052                try {
053                    return invocation.method.invoke(invocation.target, invocation.args);
054                } catch (final InvocationTargetException ite) {
055                    throw ite.getCause();
056                }
057            }
058    
059            @Override
060            protected String getCounterName(final Invocation invocation) {
061                return getCounterName(invocation.target, invocation.method);
062            }
063        }
064    
065        private static class Invocation {
066            private final Object target;
067            private final Method method;
068            private final Object[] args;
069    
070            private Invocation(final Object target, final Method method, final Object[] args) {
071                this.target = target;
072                this.method = method;
073                this.args = args;
074            }
075        }
076    }