Package org.apache.hadoop.oncrpc

Class RpcCallCache

java.lang.Object

org.apache.hadoop.oncrpc.RpcCallCache

public class RpcCallCache
extends java.lang.Object

This class is used for handling the duplicate non-idempotenty Rpc calls. A non-idempotent request is processed as follows:

• If the request is being processed for the first time, its state is in-progress in cache.
• If the request is retransimitted and is in-progress state, it is ignored.
• If the request is retransimitted and is completed, the previous response from the cache is sent back to the client.

A request is identified by the client ID (address of the client) and transaction ID (xid) from the Rpc call.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RpcCallCache.CacheEntry
static class	RpcCallCache.ClientRequest	Call that is used to track a client in the RpcCallCache

Constructor Summary

Constructors

Constructor	Description
RpcCallCache(java.lang.String program, int maxEntries)

Method Summary

Modifier and Type	Method	Description
void	callCompleted(java.net.InetAddress clientId, int xid, RpcResponse response)	Mark a request as completed and add corresponding response to the cache.
RpcCallCache.CacheEntry	checkOrAddToCache(java.net.InetAddress clientId, int xid)	Check the cache for an entry.
java.lang.String	getProgram()	Return the program name.
java.util.Iterator<java.util.Map.Entry<RpcCallCache.ClientRequest,RpcCallCache.CacheEntry>>	iterator()	Iterator to the cache entries.
int	size()	Return number of cached entries.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RpcCallCache

public RpcCallCache(java.lang.String program,
                    int maxEntries)

Method Detail

getProgram

public java.lang.String getProgram()

Return the program name.

Returns:

RPC program name

callCompleted

public void callCompleted(java.net.InetAddress clientId,
                          int xid,
                          RpcResponse response)

Mark a request as completed and add corresponding response to the cache.

Parameters:

clientId - client IP address

xid - transaction id

response - RPC response

checkOrAddToCache

public RpcCallCache.CacheEntry checkOrAddToCache(java.net.InetAddress clientId,
                                                 int xid)

Check the cache for an entry. If it does not exist, add the request as in progress.

Parameters:

clientId - client IP address

xid - transaction id

Returns:

cached entry

size

public int size()

Return number of cached entries.

Returns:

cache size

iterator

@VisibleForTesting
public java.util.Iterator<java.util.Map.Entry<RpcCallCache.ClientRequest,RpcCallCache.CacheEntry>> iterator()

Iterator to the cache entries.

Returns:

iterator cache iterator