com.ryantenney.metrics.spring.MeteredMethodInterceptor.java Source code

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Here is the source code for com.ryantenney.metrics.spring.MeteredMethodInterceptor.java

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/*
 * Copyright 2012 Ryan W Tenney (http://ryan.10e.us)
 *            and Martello Technologies (http://martellotech.com)
 *
 * 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 com.ryantenney.metrics.spring;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.aop.Pointcut;
import org.springframework.aop.support.annotation.AnnotationMatchingPointcut;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.ReflectionUtils.MethodCallback;
import org.springframework.util.ReflectionUtils.MethodFilter;

import com.codahale.metrics.Meter;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.annotation.Metered;

class MeteredMethodInterceptor implements MethodInterceptor, MethodCallback {

    private static final Logger LOG = LoggerFactory.getLogger(MeteredMethodInterceptor.class);

    public static final Pointcut POINTCUT = new AnnotationMatchingPointcut(null, Metered.class);
    public static final MethodFilter METHOD_FILTER = new AnnotationFilter(Metered.class);

    private final MetricRegistry metrics;
    private final Class<?> targetClass;
    private final Map<MethodKey, Meter> meters;

    public MeteredMethodInterceptor(final MetricRegistry metrics, final Class<?> targetClass) {
        this.metrics = metrics;
        this.targetClass = targetClass;
        this.meters = new HashMap<MethodKey, Meter>();

        LOG.debug("Creating method interceptor for class {}", targetClass.getCanonicalName());
        LOG.debug("Scanning for @Metered annotated methods");

        ReflectionUtils.doWithMethods(targetClass, this, METHOD_FILTER);
    }

    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        final Meter meter = meters.get(MethodKey.forMethod(invocation.getMethod()));
        if (meter != null) {
            meter.mark();
        }
        return invocation.proceed();
    }

    @Override
    public void doWith(Method method) throws IllegalAccessException {
        final Metered annotation = method.getAnnotation(Metered.class);
        final String metricName = Util.forMeteredMethod(targetClass, method, annotation);
        final MethodKey methodKey = MethodKey.forMethod(method);
        final Meter meter = metrics.meter(metricName);

        meters.put(methodKey, meter);

        LOG.debug("Created Meter {} for method {}", metricName, methodKey);
    }

}