com.ryantenney.metrics.spring.config.RegisterMetricBeanDefinitionParser.java Source code

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

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/**
 * 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.config;

import java.util.List;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConstructorArgumentValues;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.parsing.BeanComponentDefinition;
import org.springframework.beans.factory.parsing.CompositeComponentDefinition;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.util.StringUtils;
import org.springframework.util.xml.DomUtils;
import org.w3c.dom.Element;

import com.codahale.metrics.Metric;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.MetricSet;

import static com.ryantenney.metrics.spring.config.MetricsNamespaceHandler.METRICS_NAMESPACE;

class RegisterMetricBeanDefinitionParser implements BeanDefinitionParser {

    @Override
    public BeanDefinition parse(Element element, ParserContext parserContext) {
        final CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(),
                parserContext.extractSource(element));
        parserContext.pushContainingComponent(compDefinition);

        final String metricRegistryBeanName = element.getAttribute("metric-registry");
        if (!StringUtils.hasText(metricRegistryBeanName)) {
            throw new RuntimeException(); // TODO
        }
        final RuntimeBeanReference metricRegistryBeanRef = new RuntimeBeanReference(metricRegistryBeanName);

        final List<Element> metricElements = DomUtils.getChildElementsByTagName(element,
                new String[] { "bean", "ref" });
        for (Element metricElement : metricElements) {
            // Get the name attribute and remove it (to prevent Spring from looking for a BeanDefinitionDecorator)
            final String name = metricElement.getAttributeNS(METRICS_NAMESPACE, "name");
            if (name != null) {
                metricElement.removeAttributeNS(METRICS_NAMESPACE, "name");
            }

            final Object metric = parserContext.getDelegate().parsePropertySubElement(metricElement, null);

            final RootBeanDefinition metricRegistererDef = new RootBeanDefinition(MetricRegisterer.class);
            metricRegistererDef.setSource(parserContext.extractSource(metricElement));
            metricRegistererDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);

            final ConstructorArgumentValues args = metricRegistererDef.getConstructorArgumentValues();
            args.addIndexedArgumentValue(0, metricRegistryBeanRef);
            args.addIndexedArgumentValue(1, name);
            args.addIndexedArgumentValue(2, metric);

            final String beanName = parserContext.getReaderContext().registerWithGeneratedName(metricRegistererDef);
            parserContext.registerComponent(new BeanComponentDefinition(metricRegistererDef, beanName));
        }

        parserContext.popAndRegisterContainingComponent();

        return null;
    }

    public static class MetricRegisterer implements InitializingBean {

        private final MetricRegistry metricRegistry;
        private final String name;
        private final Metric metric;

        public MetricRegisterer(MetricRegistry metricRegistry, String name, Metric metric) {
            this.metricRegistry = metricRegistry;
            this.name = name;
            this.metric = metric;

            if (!StringUtils.hasText(name) && !(metric instanceof MetricSet)) {
                throw new RuntimeException(); // TODO
            }
        }

        @Override
        public void afterPropertiesSet() throws Exception {
            metricRegistry.register(name, metric);
        }

    }

}