java-源码-工具包-Metrics
一. 成员
ScheduledReporter成员
private final MetricRegistry registry;
private final ScheduledExecutorService executor;
private final MetricFilter filter;
private final double durationFactor;
private final String durationUnit;
private final double rateFactor;
private final String rateUnit;
ConsoleReporter成员
private static final int CONSOLE_WIDTH = 80;
private final PrintStream output;
private final Locale locale;
private final Clock clock;
private final DateFormat dateFormat; //java自带的类
二. MetricRegistry
创建MetricRegistry的实例，默认构造方法创建，内部含有metrics是一个ConcurrentHashMap
private final ConcurrentMap<String, Metric> metrics
其value是一个Metric,是一个空接口，这个空接口是什么作用呢，从类图可以看到继承关系
MetricRegistry---->MertricSet->Metric
MetricRegistry自身也是一个Mertric接口的实现,所有的数据类型都是Metric
内部包含一些getXX方法，比如：
public SortedMap<String, Gauge> getGauges() {
return getGauges(MetricFilter.ALL);
}
public SortedMap<String, Gauge> getGauges(MetricFilter filter) {
return getMetrics(Gauge.class, filter);
}
...
无参getGauges方法中，调用了MetricFilter接口如下，All是一个始终返回true的滤波器
public interface MetricFilter {
MetricFilter ALL = new MetricFilter() {
@Override
public boolean matches(String name, Metric metric) {
return true;
}
};
boolean matches(String name, Metric metric);
}
调用有参方法
public SortedMap<String, Gauge> getGauges(MetricFilter filter) {
return getMetrics(Gauge.class, filter);
}
getMertrics如下
private <T extends Metric> SortedMap<String, T> getMetrics(Class<T> klass, MetricFilter filter) {
final TreeMap<String, T> timers = new TreeMap<String, T>();
for (Map.Entry<String, Metric> entry : metrics.entrySet()) {
if (klass.isInstance(entry.getValue()) && filter.matches(entry.getKey(),
entry.getValue())) {
timers.put(entry.getKey(), (T) entry.getValue());
}
}
return Collections.unmodifiableSortedMap(timers);
}
返回一个不可变的TreeMap，这里显然是空的
三. ConsoleReporter
ConsoleReporter创建时调用构造器方法，把metrics传入，然后设置了一些默认参数
private static ConsoleReporter reporter = ConsoleReporter.forRegistry(metrics).build();
构造器默认参数
this.registry = registry;
this.output = System.out; //输出流可以配置
this.locale = Locale.getDefault();
this.clock = Clock.defaultClock();
this.timeZone = TimeZone.getDefault();
this.rateUnit = TimeUnit.SECONDS;
this.durationUnit = TimeUnit.MILLISECONDS;
this.filter = MetricFilter.ALL;
构造器调用build创建ConsoleReporter
private ConsoleReporter(MetricRegistry registry,
PrintStream output,
Locale locale,
Clock clock,
TimeZone timeZone,
TimeUnit rateUnit,
TimeUnit durationUnit,
MetricFilter filter) {
super(registry, "console-reporter", filter, rateUnit, durationUnit);
this.output = output;
this.locale = locale;
this.clock = clock;
this.dateFormat = DateFormat.getDateTimeInstance(DateFormat.SHORT,
DateFormat.MEDIUM,
locale);
dateFormat.setTimeZone(timeZone);
}
ScheduledReporter构造时调用的默认参数
protected ScheduledReporter(MetricRegistry registry,
String name,
MetricFilter filter,
TimeUnit rateUnit,
TimeUnit durationUnit) {
this.registry = registry;
this.filter = filter;
this.executor = Executors.newSingleThreadScheduledExecutor(new NamedThreadFactory(name));
this.rateFactor = rateUnit.toSeconds(1);
this.rateUnit = calculateRateUnit(rateUnit);
this.durationFactor = 1.0 / durationUnit.toNanos(1);
this.durationUnit = durationUnit.toString().toLowerCase(Locale.US);
}
start方法
reporter.start(3, TimeUnit.SECONDS);
以固定频率即3s执行,report任务
public void start(long period, TimeUnit unit) {
executor.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
report();
}
}, period, period, unit);
}
空参report如下
public void report() {
report(registry.getGauges(filter),
registry.getCounters(filter),
registry.getHistograms(filter),
registry.getMeters(filter),
registry.getTimers(filter));
}
这里调用的是带参report是抽象方法，实现在ConsoleReporter中
public void report(SortedMap<String, Gauge> gauges,
SortedMap<String, Counter> counters,
SortedMap<String, Histogram> histograms,
SortedMap<String, Meter> meters,
SortedMap<String, Timer> timers) {
final String dateTime = dateFormat.format(new Date(clock.getTime()));
printWithBanner(dateTime, '=');
output.println();
if (!gauges.isEmpty()) {
printWithBanner("-- Gauges", '-');
for (Map.Entry<String, Gauge> entry : gauges.entrySet()) {
output.println(entry.getKey());
printGauge(entry);
}
output.println();
}
if (!counters.isEmpty()) {
printWithBanner("-- Counters", '-');
for (Map.Entry<String, Counter> entry : counters.entrySet()) {
output.println(entry.getKey());
printCounter(entry);
}
output.println();
}
if (!histograms.isEmpty()) {
printWithBanner("-- Histograms", '-');
for (Map.Entry<String, Histogram> entry : histograms.entrySet()) {
output.println(entry.getKey());
printHistogram(entry.getValue());
}
output.println();
}
if (!meters.isEmpty()) {
printWithBanner("-- Meters", '-');
for (Map.Entry<String, Meter> entry : meters.entrySet()) {
output.println(entry.getKey());
printMeter(entry.getValue());
}
output.println();
}
if (!timers.isEmpty()) {
printWithBanner("-- Timers", '-');
for (Map.Entry<String, Timer> entry : timers.entrySet()) {
output.println(entry.getKey());
printTimer(entry.getValue());
}
output.println();
}
output.println();
output.flush();
}
默认的report方法就是输出所有容器的内容
四. 构造类型
Gauge接口，有一个getValue方法
public interface Gauge<T> extends Metric {
T getValue();
}
我们的调用实现这个方法
Gauge<Integer> gauge = new Gauge<Integer>() {
@Override
public Integer getValue() {
return queue.size();
}
};
调用register注册进MetricRegistry容器中
metrics.register(MetricRegistry.name(MetricsTest.class, "pending-job", "size"), gauge);
名字以.分隔的形式，这里是MetricsTest.pending-job.size
该方法源码如下
public <T extends Metric> T register(String name, T metric) throws IllegalArgumentException {
if (metric instanceof MetricSet) {
registerAll(name, (MetricSet) metric);
} else {
final Metric existing = metrics.putIfAbsent(name, metric);
if (existing == null) {
onMetricAdded(name, metric);
} else {
throw new IllegalArgumentException("A metric named " + name + " already exists");
}
}
return metric;
}
把key value加入到metrics中，然后退出
浙公网安备 33010602011771号