Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.wicket.metrics; import org.apache.wicket.Application; import org.apache.wicket.MetaDataKey; import org.apache.wicket.WicketRuntimeException; import org.aspectj.lang.ProceedingJoinPoint; import com.codahale.metrics.Counter; import com.codahale.metrics.MetricRegistry; import com.codahale.metrics.Timer.Context; /** * Base aspect provides access to the metric registry * * @author Tobias Soloschenko * */ public class WicketMetrics { /** * The name of the filter the metrics are going to collect of */ private static String filterName; private static final String APPLICATION_ERROR = "The application couldn't be resolved, please ensure to apply \"<aspect name=\"org.apache.wicket.metrics.aspects.WicketFilterInitAspect\" />\" to your aspects"; /** The key for metrics registry **/ public static final MetaDataKey<MetricRegistry> METRIC_REGISTRY = new MetaDataKey<MetricRegistry>() { private static final long serialVersionUID = 1L; }; /** The key for metrics registry **/ public static final MetaDataKey<WicketMetricsSettings> METRIC_SETTINGS = new MetaDataKey<WicketMetricsSettings>() { private static final long serialVersionUID = 1L; }; /** * Simply measure the time for a {@literal @}around * * @param name * the name of the timer context * @param joinPoint * the joinPoint to be proceed * * @return the value of the join point * @throws Throwable * if there is an exception while execution * @see org.apache.wicket.metrics.WicketMetrics#measureTime(String, ProceedingJoinPoint, * boolean) */ public Object measureTime(String name, ProceedingJoinPoint joinPoint) throws Throwable { return this.measureTime(name, joinPoint, true); } /** * Simply measure the time for a {@literal @}around * * @param name * the name of the timer context * @param joinPoint * the joinPoint to be proceed * @param renderClass * if the class name should be rendered behind the metric path * * @return the value of the join point * @throws Throwable * if there is an exception while execution */ public Object measureTime(String name, ProceedingJoinPoint joinPoint, boolean renderClass) throws Throwable { WicketMetricsSettings settings = getSettings(); MetricRegistry registry = getMetricRegistry(); if (settings.isEnabled()) { Context context = registry .timer(settings.getPrefix() + name + (renderClass ? renderClassName(joinPoint) : "")).time(); try { return proceedSilent(joinPoint); } finally { stopQuietly(context); } } else { return proceedSilent(joinPoint); } } /** * Stops the context quietly * * @param context * the context to stop */ public void stopQuietly(Context context) { if (context != null) { context.stop(); } } /** * * @author Tobias Soloschenko * */ public enum CounterOperation { /** * Increments */ INC, /** * Decrements */ DEC } /** * Creates a count of the given arguments * * @param name * the name of the meter to be marked * @param joinPoint * the join point * @param counterOperation * the operation * @param value * the value to update the counter * @return the result of the proceeded join point * @throws Throwable */ public Object count(String name, ProceedingJoinPoint joinPoint, CounterOperation counterOperation, Long value) throws Throwable { WicketMetricsSettings settings = getSettings(); MetricRegistry registry = getMetricRegistry(); if (settings.isEnabled()) { Counter counter = registry.counter(settings.getPrefix() + name + renderClassName(joinPoint)); if (counterOperation == CounterOperation.INC) { counter.inc(value); } else { counter.dec(value); } } return proceedSilent(joinPoint); } /** * Marks the meter with the given name * * @param name * the name of the meter to be marked * @param joinPoint * the join point * @return the result of the proceeded join point * @throws Throwable */ public Object mark(String name, ProceedingJoinPoint joinPoint) throws Throwable { WicketMetricsSettings settings = getSettings(); MetricRegistry registry = getMetricRegistry(); if (settings.isEnabled()) { registry.meter(settings.getPrefix() + name + renderClassName(joinPoint)).mark(); } return proceedSilent(joinPoint); } /** * Proceed the join point silent * * @param joinPoint * the join point to proceed * @return the result of the proceeded join point * @throws Throwable * if the invocation throws an error */ private Object proceedSilent(ProceedingJoinPoint joinPoint) throws Throwable { return joinPoint != null ? joinPoint.proceed() : null; } /** * Renders the class name of the given join point * * @param joinPoint * the join point to get the class of * @return the class name representation */ public String renderClassName(ProceedingJoinPoint joinPoint) { return joinPoint != null && joinPoint.getTarget() != null ? "/" + joinPoint.getTarget().getClass().getName().replace('.', '_') : ""; } /** * Gets the metric registry * * @return the metric registry */ public static synchronized MetricRegistry getMetricRegistry() { Application application = Application.get(getFilterName()); if (application == null) { throw new WicketRuntimeException(APPLICATION_ERROR); } MetricRegistry metricRegistry = application.getMetaData(METRIC_REGISTRY); if (metricRegistry == null) { metricRegistry = new MetricRegistry(); application.setMetaData(METRIC_REGISTRY, metricRegistry); } return metricRegistry; } /** * Gets the wicket metrics settings * * @return the wicket metrics settings */ public static synchronized WicketMetricsSettings getSettings() { Application application = Application.get(getFilterName()); if (application == null) { throw new WicketRuntimeException(APPLICATION_ERROR); } WicketMetricsSettings wicketMetricsSettings = application.getMetaData(METRIC_SETTINGS); if (wicketMetricsSettings == null) { wicketMetricsSettings = new WicketMetricsSettings(); wicketMetricsSettings.setPrefix(getFilterName()); application.setMetaData(METRIC_SETTINGS, wicketMetricsSettings); } return wicketMetricsSettings; } /** * Gets the filter name the application should be resolved with * * @return the filter name */ public static String getFilterName() { return filterName; } /** * Sets the filter name the application should be resolved with * * @param filterName * the filter name */ public static void setFilterName(String filterName) { WicketMetrics.filterName = filterName; } }