LookupCacheManager (Flink : Table : Runtime 2.0.1-cp2 API)

java.lang.Object
- org.apache.flink.table.runtime.functions.table.lookup.LookupCacheManager

```
@Internal
public class LookupCacheManager
extends Object
```
Managing shared caches across different subtasks.
In order to reduce the memory usage of cache, different subtasks of the same lookup join runner will share the same cache instance. Caches are managed by the identifier of the lookup table for which it is serving.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class LookupCacheManager.RefCountedCache
A wrapper class of LookupCache which also tracks the reference count of it.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`checkAllReleased()`
`void`	`clear()`
`static LookupCacheManager`	`getInstance()`	Get the shared instance of `LookupCacheManager`.
`Map<String,LookupCacheManager.RefCountedCache>`	`getManagedCaches()`
`static void`	`keepCacheOnRelease(boolean toKeep)`
`org.apache.flink.table.connector.source.lookup.cache.LookupCache`	`registerCacheIfAbsent(String cacheIdentifier, org.apache.flink.table.connector.source.lookup.cache.LookupCache cache)`	Register a cache instance with identifier to the manager.
`void`	`unregisterCache(String cacheIdentifier)`	Release the cache with the given identifier from the manager.

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

- Method Detail
  - getInstance
```
public static LookupCacheManager getInstance()
```
    Get the shared instance of LookupCacheManager.
  - registerCacheIfAbsent
```
public org.apache.flink.table.connector.source.lookup.cache.LookupCache registerCacheIfAbsent(String cacheIdentifier,
                                                                                              org.apache.flink.table.connector.source.lookup.cache.LookupCache cache)
```
    Register a cache instance with identifier to the manager.
    If the cache with the given identifier is already registered in the manager, this method will return the registered one, otherwise this method will register the given cache into the manager then return.
    
    Parameters:
    
    cacheIdentifier - identifier of the cache
    
    cache - instance of cache trying to register
    
    Returns:
    
    instance of the shared cache
  - unregisterCache
```
public void unregisterCache(String cacheIdentifier)
```
    Release the cache with the given identifier from the manager.
    The manager will track a reference count of managed caches, and will close the cache if the reference count reaches 0.
  - keepCacheOnRelease
```
public static void keepCacheOnRelease(boolean toKeep)
```
  - checkAllReleased
```
public void checkAllReleased()
```
  - clear
```
public void clear()
```
  - getManagedCaches
```
public Map<String,LookupCacheManager.RefCountedCache> getManagedCaches()
```