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Add comments to ClassLoader scoped weak map

This commit is contained in:
Luca Abbati 2019-07-16 11:00:48 +02:00
parent de6f33c035
commit bfa5712c04
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1 changed files with 9 additions and 0 deletions
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9
dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/ClassLoaderScopedWeakMap.java
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@ -4,12 +4,17 @@ import datadog.trace.bootstrap.WeakMap;
import java.util.HashMap; import java.util.HashMap;
import java.util.Map; import java.util.Map;
/** A registry which is scoped per-classloader able to hold key-value pairs with weak keys. */
public class ClassLoaderScopedWeakMap { public class ClassLoaderScopedWeakMap {
public static final ClassLoaderScopedWeakMap INSTANCE = new ClassLoaderScopedWeakMap(); public static final ClassLoaderScopedWeakMap INSTANCE = new ClassLoaderScopedWeakMap();
private final WeakMap<ClassLoader, Map<Object, Object>> map = WeakMap.Supplier.DEFAULT.get(); private final WeakMap<ClassLoader, Map<Object, Object>> map = WeakMap.Supplier.DEFAULT.get();
/**
* Gets the element registered at the specified key or register as new one retrieved by the
* provided supplier.
*/
public synchronized Object getOrCreate( public synchronized Object getOrCreate(
ClassLoader classLoader, Object key, Supplier valueSupplier) { ClassLoader classLoader, Object key, Supplier valueSupplier) {
Map<Object, Object> classLoaderMap = map.get(classLoader); Map<Object, Object> classLoaderMap = map.get(classLoader);
@ -27,6 +32,10 @@ public class ClassLoaderScopedWeakMap {
return value; return value;
} }
/**
* Supplies the value to be stored and it is called only when a value does not exists yet in the
* registry.
*/
public interface Supplier { public interface Supplier {
Object get(); Object get();
} }