/**
* Copyright (C) 2012 Ryan W Tenney (ryan@10e.us)
*
* 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.Field;
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_FIELDS;
class GaugeFieldAnnotationBeanPostProcessor extends AbstractAnnotationBeanPostProcessor implements Ordered {
private static final AnnotationFilter FILTER = new AnnotationFilter(Gauge.class, INSTANCE_FIELDS);
private final MetricRegistry metrics;
public GaugeFieldAnnotationBeanPostProcessor(final MetricRegistry metrics) {
super(Members.ALL, Phase.PRE_INIT, FILTER);
this.metrics = metrics;
}
@Override
protected void withField(final Object bean, String beanName, Class<?> targetClass, final Field field) {
ReflectionUtils.makeAccessible(field);
final Gauge annotation = field.getAnnotation(Gauge.class);
final String metricName = Util.forGauge(targetClass, field, annotation);
metrics.register(metricName, new com.codahale.metrics.Gauge<Object>() {
@Override
public Object getValue() {
Object value = ReflectionUtils.getField(field, bean);
if (value instanceof com.codahale.metrics.Gauge) {
value = ((com.codahale.metrics.Gauge<?>) value).getValue();
}
return value;
}
});
LOG.debug("Created gauge {} for field {}.{}", metricName, targetClass.getCanonicalName(), field.getName());
}
@Override
public int getOrder() {
return LOWEST_PRECEDENCE;
}
}