import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
/**
 * Acquires the named cached gauge 
 * @param name The name of the gauge
 * @param provider The value provider for the gauge
 * @param refreshPeriod The refresh period of the cached gauge in seconds
 * @return the cached gauge
 */
public <T> CachedGauge<T> gauge(final String name, final Callable<T> provider, final int refreshPeriod) {
	final String fullName = name + serviceTag;
	final CachedGauge<T> g = new CachedGauge<T>(refreshPeriod, TimeUnit.SECONDS) {
		@Override
		protected T loadValue() {
			try {
			return provider.call();
			} catch (Exception ex) {
				throw new RuntimeException("Failed to get cached value for [" + name + "]", ex);
			}
		}
	};
	metricRegistry.register("gauge." + fullName, g);
	gauges.put(name, g);
	return g;
}
 

import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
private void registerAggregateMetrics(final MetricRegistry registry) {
    //
    // JVM used percentage
    //
    Map<String, Gauge> gauges = registry.getGauges();
    final Gauge<Long> gaugeJvmMemMax = gauges.get("jvm.memory.total.max");
    final Gauge<Long> gaugeJvmMemUsed = gauges.get("jvm.memory.total.used");
    
    registry.register(JVM_MEM_PERC.key(), new CachedGauge<Double>(5L, TimeUnit.SECONDS) {
        
        @Override
        protected Double loadValue() {
            double memMax = gaugeJvmMemMax.getValue();
            double memUsed = gaugeJvmMemUsed.getValue();
            return (memUsed / memMax) * 100.0d;
        }
    });
}
 

import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
/**
 * {@inheritDoc}
 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
 */
@Override
public void afterPropertiesSet() throws Exception {		
	configDir = new File(configDirName).getAbsoluteFile();
	appDir = new File(appDirName).getAbsoluteFile();
	if(!configDir.isDirectory()) throw new IllegalArgumentException("The configuration directory [" + configDirName + "] is invalid");
	if(!appDir.exists()) {
		appDir.mkdirs();
	}
	if(!appDir.isDirectory()) throw new IllegalArgumentException("The app directory [" + appDirName + "] is invalid");
	log.info("Configuration Directory: [{}]", configDir);
	if(!cacheSpec.contains("recordStats")) cacheSpec = cacheSpec + ",recordStats";
	
	configCache = CacheBuilder.from(cacheSpec).build(configCacheLoader);
	configCacheStats = new CachedGauge<CacheStats>(5, TimeUnit.SECONDS) {
		@Override
		protected CacheStats loadValue() {				
			return configCache.stats();
		}
	};
	appJarCache = CacheBuilder.from(cacheSpec).build(appJarCacheLoader);
	appJarCacheStats = new CachedGauge<CacheStats>(5, TimeUnit.SECONDS) {
		@Override
		protected CacheStats loadValue() {				
			return appJarCache.stats();
		}
	};
	
	reloadConfigCache();
	log.info("Loaded [{}] App Configurations", configCache.size());
	reloadAppJarCache();
	log.info("Loaded [{}] App Jar Sets", appJarCache.size());
}
 

import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
/**
 * Creates a new TSDBEndpoint
 * @param sqlWorker The SQLWorker that will drive the lookups
 */
private TSDBEndpoint(final SQLWorker sqlWorker) {
	this.sqlWorker = sqlWorker;
	knownServers = new CachedGauge<String[]>(60, TimeUnit.SECONDS) {
		@Override
		protected String[] loadValue() {
			final String order = (asc.getAndSet(asc.get()) ? "ASC" : "DESC"); 
			return sqlWorker.sqlForFormat(null, null, "SELECT HOST, PORT, URI FROM TSD_KNOWNSERVERS WHERE UP = 'Y' ORDER BY HOST " + order + ", PORT " + order, "http://##0##:##1##/##2##");
		}
	};
}
 

import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
public CachedGaugeImpl(String name, Level level, long timeout, TimeUnit timeoutUnit, final Gauge<T> gauge) {
    super(name, level);
    this.gauge = new CachedGauge<T>(timeout, timeoutUnit) {
        @Override
        protected T loadValue() {
            return gauge.getValue();
        }
    };
}
 

import com.codahale.metrics.CachedGauge; //导入依赖的package包/类
public static <T> void measureCachedGauge( String metric, long timeout, TimeUnit timeUnit, Supplier<T> get ) {
    registry.register( metric, new CachedGauge<T>( timeout, timeUnit ) {
        @Override
        protected T loadValue() {
            return get.get();
        }
    } );
}