org.apache.tez.runtime.api

Interface ObjectRegistry

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public interface ObjectRegistry

A simple shared object registry to cache objects in the memory of the container running the task. This registry can be used to avoid re-creating objects like common hash-tables, dictionaries etc. and provide performance improvements. The cached objects have different life-cycles. If a task adds an object to the cache with Vertex life-cycle then that object is in the cache while the Vertex (to which the task belongs) is running. DAG life-cycle is while the DAG (to which that task belongs) is running. Session life-cycle is while the session (to which that task belongs) is running.
This interface is not supposed to be implemented by users.

Method Summary

Modifier and Type	Method and Description
Object	cacheForDAG(String key, Object value) Insert or update object into the registry with DAG life-cycle.
Object	cacheForSession(String key, Object value) Insert or update object into the registry with Session life-cycle.
Object	cacheForVertex(String key, Object value) Insert or update object into the registry with Vertex life-cycle.
boolean	delete(String key) Delete the object associated with the provided key
Object	get(String key) Return the object associated with the provided key

Method Detail

cacheForVertex

Object cacheForVertex(String key,
                      Object value)

Insert or update object into the registry with Vertex life-cycle. This will remove an object associated with the same key with a different life-cycle as there is only one instance of an Object stored for a given key irrespective of the life-cycle attached to the Object. The object may stay in the cache while the Vertex (to which the task belongs) is running.

Parameters:

key - Key to identify the Object

value - Object to be inserted

Returns:

Previous Object associated with the key attached if present else null. Could return the same object if the object was associated with the same key for a different life-cycle.

cacheForDAG

Object cacheForDAG(String key,
                   Object value)

Insert or update object into the registry with DAG life-cycle. This will remove an object associated with the same key with a different life-cycle as there is only one instance of an Object stored for a given key irrespective of the life-cycle attached to the Object. The object may stay in the cache while the DAG (to which the task belongs) is running.

Parameters:

key - Key to identify the Object

value - Object to be inserted

Returns:

Previous Object associated with the key attached if present else null. Could return the same object if the object was associated with the same key for a different life-cycle.

cacheForSession

Object cacheForSession(String key,
                       Object value)

Insert or update object into the registry with Session life-cycle. This will remove an object associated with the same key with a different life-cycle as there is only one instance of an Object stored for a given key irrespective of the life-cycle attached to the Object. The object may stay in the cache while the Session (to which the task belongs) is running.

Parameters:

key - Key to identify the Object

value - Object to be inserted

Returns:

Previous Object associated with the key attached if present else null. Could return the same object if the object was associated with the same key for a different life-cycle.

get

Object get(String key)

Return the object associated with the provided key

Parameters:

key - Key to find object

Returns:

Object if found else null

delete

boolean delete(String key)

Delete the object associated with the provided key

Parameters:

key - Key to find object

Returns:

True if an object was found and removed