com.emc.mongoose.api.metrics.CustomMetricRegistry Maven / Gradle / Ivy
Show all versions of mongoose-api-metrics Show documentation
package com.emc.mongoose.api.metrics;
import com.codahale.metrics.Counter;
import com.codahale.metrics.ExponentiallyDecayingReservoir;
import com.codahale.metrics.Gauge;
import com.codahale.metrics.Histogram;
import com.codahale.metrics.Meter;
import com.codahale.metrics.Metric;
import com.codahale.metrics.MetricFilter;
import com.codahale.metrics.MetricRegistryListener;
import com.codahale.metrics.MetricSet;
import com.codahale.metrics.Timer;
import java.io.Closeable;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* A registry of metric instances.
*/
public final class CustomMetricRegistry
implements Closeable, MetricSet {
/**
* Concatenates elements to form a dotted name, eliding any null values or empty strings.
*
* @param name the first element of the name
* @param names the remaining elements of the name
* @return {@code name} and {@code names} concatenated by periods
*/
public static String name(final String name, final String... names) {
final StringBuilder builder = new StringBuilder();
append(builder, name);
if(names != null) {
for(String s : names) {
append(builder, s);
}
}
return builder.toString();
}
/**
* Concatenates a class name and elements to form a dotted name, eliding any null values or
* empty strings.
*
* @param klass the first element of the name
* @param names the remaining elements of the name
* @return {@code klass} and {@code names} concatenated by periods
*/
public static String name(final Class klass, final String... names) {
return name(klass.getName(), names);
}
private static void append(StringBuilder builder, String part) {
if(part != null && !part.isEmpty()) {
if(builder.length() > 0) {
builder.append('.');
}
builder.append(part);
}
}
private final ConcurrentMap metrics;
private final List listeners;
/**
* Creates a new {@link CustomMetricRegistry}.
*/
public CustomMetricRegistry() {
this.metrics = buildMap();
this.listeners = new CopyOnWriteArrayList();
}
/**
* Creates a new {@link ConcurrentMap} implementation for use inside the registry. Override this
* to create a {@link CustomMetricRegistry} with space- or time-bounded metric lifecycles, for
* example.
*
* @return a new {@link ConcurrentMap}
*/
private ConcurrentMap buildMap() {
return new ConcurrentHashMap<>();
}
/**
* Given a {@link Metric}, registers it under the given name.
*
* @param name the name of the metric
* @param metric the metric
* @param the type of the metric
* @return {@code metric}
* @throws IllegalArgumentException if the name is already registered
*/
@SuppressWarnings("unchecked")
public final T register(final String name, final 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;
}
/**
* Given a metric set, registers them.
*
* @param metrics a set of metrics
* @throws IllegalArgumentException if any of the names are already registered
*/
public final void registerAll(final MetricSet metrics) throws IllegalArgumentException {
registerAll(null, metrics);
}
/**
* Return the {@link Counter} registered under this name; or create and register
* a new {@link Counter} if none is registered.
*
* @param name the name of the metric
* @return a new or pre-existing {@link Counter}
*/
public final Counter counter(final String name) {
return getOrAdd(name, MetricBuilder.COUNTERS);
}
/**
* Return the {@link Histogram} registered under this name; or create and register
* a new {@link Histogram} if none is registered.
*
* @param name the name of the metric
* @return a new or pre-existing {@link Histogram}
*/
public final Histogram histogram(final String name) {
return getOrAdd(name, MetricBuilder.HISTOGRAMS);
}
/**
* Return the {@link Meter} registered under this name; or create and register
* a new {@link Meter} if none is registered.
*
* @param name the name of the metric
* @return a new or pre-existing {@link Meter}
*/
public final Meter meter(final String name) {
return getOrAdd(name, MetricBuilder.METERS);
}
/**
* Return the {@link Timer} registered under this name; or create and register
* a new {@link Timer} if none is registered.
*
* @param name the name of the metric
* @return a new or pre-existing {@link Timer}
*/
public final Timer timer(final String name) {
return getOrAdd(name, MetricBuilder.TIMERS);
}
/**
* Removes the metric with the given name.
*
* @param name the name of the metric
* @return whether or not the metric was removed
*/
public final boolean remove(final String name) {
final Metric metric = metrics.remove(name);
if(metric != null) {
onMetricRemoved(name, metric);
return true;
}
return false;
}
/**
* Removes all metrics which match the given filter.
*
* @param filter a filter
*/
public final void removeMatching(final MetricFilter filter) {
for(Map.Entry entry : metrics.entrySet()) {
if(filter.matches(entry.getKey(), entry.getValue())) {
remove(entry.getKey());
}
}
}
/**
* Adds a {@link MetricRegistryListener} to a collection of listeners that will be notified on
* metric creation. Listeners will be notified in the order in which they are added.
*
* N.B.: The listener will be notified of all existing metrics when it first registers.
*
* @param listener the listener that will be notified
*/
public final void addListener(final MetricRegistryListener listener) {
listeners.add(listener);
for(Map.Entry entry : metrics.entrySet()) {
notifyListenerOfAddedMetric(listener, entry.getValue(), entry.getKey());
}
}
/**
* Removes a {@link MetricRegistryListener} from this registry's collection of listeners.
*
* @param listener the listener that will be removed
*/
public final void removeListener(final MetricRegistryListener listener) {
listeners.remove(listener);
}
/**
* Returns a set of the names of all the metrics in the registry.
*
* @return the names of all the metrics
*/
public final SortedSet getNames() {
return Collections.unmodifiableSortedSet(new TreeSet(metrics.keySet()));
}
/**
* Returns a map of all the gauges in the registry and their names.
*
* @return all the gauges in the registry
*/
public final SortedMap getGauges() {
return getGauges(MetricFilter.ALL);
}
/**
* Returns a map of all the gauges in the registry and their names which match the given filter.
*
* @param filter the metric filter to match
* @return all the gauges in the registry
*/
public final SortedMap getGauges(final MetricFilter filter) {
return getMetrics(Gauge.class, filter);
}
/**
* Returns a map of all the counters in the registry and their names.
*
* @return all the counters in the registry
*/
public final SortedMap getCounters() {
return getCounters(MetricFilter.ALL);
}
/**
* Returns a map of all the counters in the registry and their names which match the given
* filter.
*
* @param filter the metric filter to match
* @return all the counters in the registry
*/
public final SortedMap getCounters(final MetricFilter filter) {
return getMetrics(Counter.class, filter);
}
/**
* Returns a map of all the histograms in the registry and their names.
*
* @return all the histograms in the registry
*/
public final SortedMap getHistograms() {
return getHistograms(MetricFilter.ALL);
}
/**
* Returns a map of all the histograms in the registry and their names which match the given
* filter.
*
* @param filter the metric filter to match
* @return all the histograms in the registry
*/
public final SortedMap getHistograms(final MetricFilter filter) {
return getMetrics(Histogram.class, filter);
}
/**
* Returns a map of all the meters in the registry and their names.
*
* @return all the meters in the registry
*/
public final SortedMap getMeters() {
return getMeters(MetricFilter.ALL);
}
/**
* Returns a map of all the meters in the registry and their names which match the given filter.
*
* @param filter the metric filter to match
* @return all the meters in the registry
*/
public final SortedMap getMeters(final MetricFilter filter) {
return getMetrics(Meter.class, filter);
}
/**
* Returns a map of all the timers in the registry and their names.
*
* @return all the timers in the registry
*/
public final SortedMap getTimers() {
return getTimers(MetricFilter.ALL);
}
/**
* Returns a map of all the timers in the registry and their names which match the given filter.
*
* @param filter the metric filter to match
* @return all the timers in the registry
*/
public final SortedMap getTimers(final MetricFilter filter) {
return getMetrics(Timer.class, filter);
}
@SuppressWarnings("unchecked")
private T getOrAdd(final String name, final MetricBuilder builder) {
final Metric metric = metrics.get(name);
if(builder.isInstance(metric)) {
return (T) metric;
} else if(metric == null) {
try {
return register(name, builder.newMetric());
} catch (IllegalArgumentException e) {
final Metric added = metrics.get(name);
if(builder.isInstance(added)) {
return (T) added;
}
}
}
throw new IllegalArgumentException(name + " is already used for a different type of metric");
}
@SuppressWarnings("unchecked")
private SortedMap getMetrics(
final Class klass, final MetricFilter filter
) {
final TreeMap timers = new TreeMap();
for(final Map.Entry 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);
}
private void onMetricAdded(final String name, final Metric metric) {
for(final MetricRegistryListener listener : listeners) {
notifyListenerOfAddedMetric(listener, metric, name);
}
}
private void notifyListenerOfAddedMetric(
final MetricRegistryListener listener, final Metric metric, final String name
) {
if(metric instanceof Gauge) {
listener.onGaugeAdded(name, (Gauge) metric);
} else if(metric instanceof Counter) {
listener.onCounterAdded(name, (Counter) metric);
} else if(metric instanceof Histogram) {
listener.onHistogramAdded(name, (Histogram) metric);
} else if(metric instanceof Meter) {
listener.onMeterAdded(name, (Meter) metric);
} else if(metric instanceof Timer) {
listener.onTimerAdded(name, (Timer) metric);
} else {
throw new IllegalArgumentException("Unsupported metric type: " + metric.getClass());
}
}
private void onMetricRemoved(final String name, final Metric metric) {
for(final MetricRegistryListener listener : listeners) {
notifyListenerOfRemovedMetric(name, metric, listener);
}
}
private void notifyListenerOfRemovedMetric(
final String name, final Metric metric, final MetricRegistryListener listener
) {
if(metric instanceof Gauge) {
listener.onGaugeRemoved(name);
} else if(metric instanceof Counter) {
listener.onCounterRemoved(name);
} else if(metric instanceof Histogram) {
listener.onHistogramRemoved(name);
} else if(metric instanceof Meter) {
listener.onMeterRemoved(name);
} else if(metric instanceof Timer) {
listener.onTimerRemoved(name);
} else {
throw new IllegalArgumentException("Unsupported metric type: " + metric.getClass());
}
}
private void registerAll(final String prefix, final MetricSet metrics)
throws IllegalArgumentException {
for(final Map.Entry entry : metrics.getMetrics().entrySet()) {
if(entry.getValue() instanceof MetricSet) {
registerAll(name(prefix, entry.getKey()), (MetricSet) entry.getValue());
} else {
register(name(prefix, entry.getKey()), entry.getValue());
}
}
}
@Override
public final Map getMetrics() {
return Collections.unmodifiableMap(metrics);
}
@Override
public final void close()
throws IOException {
metrics.clear();
listeners.clear();
}
/**
* A quick and easy way of capturing the notion of default metrics.
*/
private interface MetricBuilder {
MetricBuilder COUNTERS = new MetricBuilder() {
@Override
public Counter newMetric() {
return new Counter();
}
@Override
public boolean isInstance(final Metric metric) {
return Counter.class.isInstance(metric);
}
};
MetricBuilder HISTOGRAMS = new MetricBuilder() {
@Override
public Histogram newMetric() {
return new Histogram(new ExponentiallyDecayingReservoir());
}
@Override
public boolean isInstance(final Metric metric) {
return Histogram.class.isInstance(metric);
}
};
MetricBuilder METERS = new MetricBuilder() {
@Override
public Meter newMetric() {
return new Meter();
}
@Override
public boolean isInstance(final Metric metric) {
return Meter.class.isInstance(metric);
}
};
MetricBuilder TIMERS = new MetricBuilder() {
@Override
public Timer newMetric() {
return new Timer();
}
@Override
public boolean isInstance(final Metric metric) {
return Timer.class.isInstance(metric);
}
};
T newMetric();
boolean isInstance(final Metric metric);
}
}