com.ryantenney.metrics.spring.GaugeMethodAnnotationBeanPostProcessor Maven / Gradle / Ivy

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/**
 * Copyright (C) 2012 Ryan W Tenney ([email protected])
 *
 * 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 org.springframework.core.Ordered;
import org.springframework.util.ReflectionUtils;

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.annotation.Gauge;

import static com.ryantenney.metrics.spring.AnnotationFilter.INSTANCE_METHODS;

class GaugeMethodAnnotationBeanPostProcessor extends AbstractAnnotationBeanPostProcessor implements Ordered {

	private static final AnnotationFilter FILTER = new AnnotationFilter(Gauge.class, INSTANCE_METHODS);

	private final MetricRegistry metrics;

	public GaugeMethodAnnotationBeanPostProcessor(final MetricRegistry metrics) {
		super(Members.ALL, Phase.POST_INIT, FILTER);
		this.metrics = metrics;
	}

	@Override
	protected void withMethod(final Object bean, String beanName, Class targetClass, final Method method) {
		if (method.getParameterTypes().length > 0) {
			throw new IllegalStateException("Method " + method.getName() + " is annotated with @Gauge but requires parameters.");
		}

		final Gauge annotation = method.getAnnotation(Gauge.class);
		final String metricName = Util.forGauge(targetClass, method, annotation);

		metrics.register(metricName, new com.codahale.metrics.Gauge