package com.codahale.metrics;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicReference;
A map of shared, named metric registries.
/**
* A map of shared, named metric registries.
*/
public class SharedMetricRegistries {
private static final ConcurrentMap<String, MetricRegistry> REGISTRIES =
new ConcurrentHashMap<>();
private static AtomicReference<String> defaultRegistryName = new AtomicReference<>();
/* Visible for testing */
static void setDefaultRegistryName(AtomicReference<String> defaultRegistryName) {
SharedMetricRegistries.defaultRegistryName = defaultRegistryName;
}
private SharedMetricRegistries() { /* singleton */ }
public static void clear() {
REGISTRIES.clear();
}
public static Set<String> names() {
return REGISTRIES.keySet();
}
public static void remove(String key) {
REGISTRIES.remove(key);
}
public static MetricRegistry add(String name, MetricRegistry registry) {
return REGISTRIES.putIfAbsent(name, registry);
}
public static MetricRegistry getOrCreate(String name) {
final MetricRegistry existing = REGISTRIES.get(name);
if (existing == null) {
final MetricRegistry created = new MetricRegistry();
final MetricRegistry raced = add(name, created);
if (raced == null) {
return created;
}
return raced;
}
return existing;
}
Creates a new registry and sets it as the default one under the provided name.
Params: - name – the registry name
Throws: - IllegalStateException – if the name has already been set
Returns: the default registry
/**
* Creates a new registry and sets it as the default one under the provided name.
*
* @param name the registry name
* @return the default registry
* @throws IllegalStateException if the name has already been set
*/
public synchronized static MetricRegistry setDefault(String name) {
final MetricRegistry registry = getOrCreate(name);
return setDefault(name, registry);
}
Sets the provided registry as the default one under the provided name
Params: - name – the default registry name
- metricRegistry – the default registry
Throws: - IllegalStateException – if the default registry has already been set
/**
* Sets the provided registry as the default one under the provided name
*
* @param name the default registry name
* @param metricRegistry the default registry
* @throws IllegalStateException if the default registry has already been set
*/
public static MetricRegistry setDefault(String name, MetricRegistry metricRegistry) {
if (defaultRegistryName.compareAndSet(null, name)) {
add(name, metricRegistry);
return metricRegistry;
}
throw new IllegalStateException("Default metric registry name is already set.");
}
Gets the name of the default registry, if it has been set
Throws: - IllegalStateException – if the default has not been set
Returns: the default registry
/**
* Gets the name of the default registry, if it has been set
*
* @return the default registry
* @throws IllegalStateException if the default has not been set
*/
public static MetricRegistry getDefault() {
MetricRegistry metricRegistry = tryGetDefault();
if (metricRegistry == null) {
throw new IllegalStateException("Default registry name has not been set.");
}
return metricRegistry;
}
Same as getDefault()
except returns null when the default registry has not been set. Returns: the default registry or null
/**
* Same as {@link #getDefault()} except returns null when the default registry has not been set.
*
* @return the default registry or null
*/
public static MetricRegistry tryGetDefault() {
final String name = defaultRegistryName.get();
if (name != null) {
return getOrCreate(name);
} else {
return null;
}
}
}