ReferenceCountingMap

java.lang.Object
- io.grpc.xds.internal.security.ReferenceCountingMap<K,V>

Type Parameters:

K - Key type for the map

V - Value type for the map - it should be a Closeable
```
@ThreadSafe
public final class ReferenceCountingMap<K,V extends Closeable>
extends java.lang.Object
```
A map for managing reference-counted shared resources - typically providers.
A key (of generic type K) identifies a provider (of generic type V). The map also depends on a factory ReferenceCountingMap.ValueFactory to create a new instance of V as needed. Values are ref-counted and closed by calling Closeable.close() when ref-count reaches zero.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`private static class`	`ReferenceCountingMap.Instance<V extends Closeable>`
`static interface`	`ReferenceCountingMap.ValueFactory<K,V extends Closeable>`	A factory to create a value from the given key.

Field Summary

Fields
Modifier and Type Field Description

private java.util.Map<K,ReferenceCountingMap.Instance<V>> instances

private ReferenceCountingMap.ValueFactory<K,V> valueFactory

Constructor Summary

Constructors
Constructor Description

ReferenceCountingMap(ReferenceCountingMap.ValueFactory<K,V> valueFactory)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`V`	`get(K key)`	Gets an existing instance of a provider.
`private V`	`getInternal(K key)`
`V`	`release(K key, V value)`	Releases an instance of the given value.
`private V`	`releaseInternal(K key, V value)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - instances
```
private final java.util.Map<K,ReferenceCountingMap.Instance<V extends Closeable>> instances
```
  - valueFactory
```
private final ReferenceCountingMap.ValueFactory<K,V extends Closeable> valueFactory
```
- Constructor Detail
  - ReferenceCountingMap
```
public ReferenceCountingMap(ReferenceCountingMap.ValueFactory<K,V> valueFactory)
```
- Method Detail
  - get
```
@CheckReturnValue
public V get(K key)
```
    Gets an existing instance of a provider. If it doesn't exist, creates a new one using the provided <K, V>
  - release
```
public V release(K key,
                 V value)
```
    Releases an instance of the given value.
    The instance must have been obtained from get(Object). Otherwise will throw IllegalArgumentException.
    Caller must not release a reference more than once. It's advised that you clear the reference to the instance with the null returned by this method.
    
    Parameters:
    
    key - for the instance to be released
    
    value - the instance to be released
    
    Returns:
    
    a null which the caller can use to clear the reference to that instance.
  - getInternal
```
private V getInternal(K key)
```
  - releaseInternal
```
private V releaseInternal(K key,
                          V value)
```