org.apache.hadoop.oncrpc
Class RpcCallCache

java.lang.Object
  org.apache.hadoop.oncrpc.RpcCallCache

public class RpcCallCache
extends 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

static class	RpcCallCache.CacheEntry
static class	RpcCallCache.ClientRequest Call that is used to track a client in the RpcCallCache

Constructor Summary

RpcCallCache(String program, int maxEntries)

Method Summary

void	callCompleted(InetAddress clientId, int xid, RpcResponse response) Mark a request as completed and add corresponding response to the cache
RpcCallCache.CacheEntry	checkOrAddToCache(InetAddress clientId, int xid) Check the cache for an entry.
String	getProgram() Return the program name
Iterator<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(String program,
                    int maxEntries)

Method Detail

getProgram

public String getProgram()

Return the program name

callCompleted

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

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

checkOrAddToCache

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

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

size

public int size()

Return number of cached entries

iterator

public Iterator<Map.Entry<RpcCallCache.ClientRequest,RpcCallCache.CacheEntry>> iterator()

Iterator to the cache entries

Returns:

iterator