rice.p2p.past
Class PastImpl

java.lang.Object
  rice.p2p.past.PastImpl

All Implemented Interfaces:

Application, Past, ReplicationManagerClient

Direct Known Subclasses:

GCPastImpl

public class PastImpl

extends java.lang.Object

implements Past, Application, ReplicationManagerClient

Version:

$Id: PastImpl.java 2866 2005-12-20 15:57:54Z jstewart $

Author:

Alan Mislove, Ansley Post, Peter Druschel

Nested Class Summary

static interface

PastImpl.MessageBuilder Class which builds a message

Field Summary

protected Cache	backup DESCRIBE THE FIELD
protected Endpoint	endpoint DESCRIBE THE FIELD
protected Environment	environment DESCRIBE THE FIELD
protected IdFactory	factory DESCRIBE THE FIELD
int	fetchHandles DESCRIBE THE FIELD
int	inserts DESCRIBE THE FIELD
protected java.lang.String	instance DESCRIBE THE FIELD
protected Logger	logger DESCRIBE THE FIELD
int	lookups DESCRIBE THE FIELD
int	MESSAGE_TIMEOUT DESCRIBE THE FIELD
int	other DESCRIBE THE FIELD
protected PastPolicy	policy DESCRIBE THE FIELD
protected ReplicationManager	replicaManager DESCRIBE THE FIELD
protected int	replicationFactor DESCRIBE THE FIELD
protected StorageManager	storage DESCRIBE THE FIELD
double	SUCCESSFUL_INSERT_THRESHOLD DESCRIBE THE FIELD
protected StorageManager	trash DESCRIBE THE FIELD

Constructor Summary

PastImpl(Node node, StorageManager manager, Cache backup, int replicas, java.lang.String instance, PastPolicy policy, StorageManager trash)
Constructor for Past

PastImpl(Node node, StorageManager manager, int replicas, java.lang.String instance)
Constructor for Past, using the default policy

PastImpl(Node node, StorageManager manager, int replicas, java.lang.String instance, PastPolicy policy)
Constructor for Past

Method Summary

protected ReplicationManager	buildReplicationManager(Node node, java.lang.String instance) Internal method which builds the replication manager.
void	cache(PastContent content, Continuation command) Method which inserts the given object into the cache
void	deliver(Id id, Message message) This method is called on the application at the destination node for the given id.
protected void	doInsert(Id id, PastImpl.MessageBuilder builder, Continuation command) Internal method which actually performs an insert for a given object.
boolean	exists(Id id) This upcall should return whether or not the given id is currently stored by the client.
void	existsInOverlay(Id id, Continuation command) DESCRIBE THE METHOD
void	fetch(Id id, NodeHandle hint, Continuation command) This upcall is invoked to tell the client to fetch the given id, and to call the given command with the boolean result once the fetch is completed.
void	fetch(PastContentHandle handle, Continuation command) Retrieves the object associated with a given content handle.
boolean	forward(RouteMessage message) This method is invoked on applications when the underlying node is about to forward the given message with the provided target to the specified next hop.
Endpoint	getEndpoint() Returns the endpoint associated with the Past - ONLY FOR TESTING - DO NOT USE
Environment	getEnvironment() Gets the Environment attribute of the PastImpl object
protected void	getHandles(Id id, int max, Continuation command) Internal method which returns the handles to an object.
java.lang.String	getInstance() Gets the Instance attribute of the PastImpl object
NodeHandle	getLocalNodeHandle() get the nodeHandle of the local Past node
Continuation[]	getOutstandingMessages() Returns of the outstanding messages.
Replication	getReplication() Returns the replica manager for this Past instance.
int	getReplicationFactor() Returns the number of replicas used in this Past
protected Continuation	getResponseContinuation(PastMessage msg) Returns a continuation which will respond to the given message.
StorageManager	getStorageManager() Returns this Past's storage manager.
protected int	getUID() Returns a new uid for a message
void	insert(PastContent obj, Continuation command) Inserts an object with the given ID into this instance of Past.
void	lookup(Id id, boolean cache, Continuation command) Method which performs the same as lookup(), but allows the callee to specify if the data should be cached.
void	lookup(Id id, Continuation command) Retrieves the object stored in this instance of Past with the given ID.
void	lookupHandle(Id id, NodeHandle handle, Continuation command) Retrieves the handle for the given object stored on the requested node.
void	lookupHandles(Id id, int max, Continuation command) Retrieves the handles of up to max replicas of the object stored in this instance of Past with the given ID.
void	reInsert(Id id, Continuation command) DESCRIBE THE METHOD
void	remove(Id id, Continuation command) This upcall is to notify the client that the given id can be safely removed from the storage.
IdSet	scan() This upcall should return the set of keys that the application currently stores.
IdSet	scan(IdRange range) This upcall should return the set of keys that the application currently stores in this range.
protected void	sendRequest(Id id, PastMessage message, Continuation command) Sends a request message across the wire, and stores the appropriate continuation.
protected void	sendRequest(Id id, PastMessage message, NodeHandle hint, Continuation command) Sends a request message across the wire, and stores the appropriate continuation.
protected void	sendRequest(NodeHandle handle, PastMessage message, Continuation command) Sends a request message across the wire, and stores the appropriate continuation.
void	update(NodeHandle handle, boolean joined) This method is invoked to inform the application that the given node has either joined or left the neighbor set of the local node, as the set would be returned by the neighborSet call.

Methods inherited from class java.lang.Object

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

Field Detail

MESSAGE_TIMEOUT

public final int MESSAGE_TIMEOUT

DESCRIBE THE FIELD

SUCCESSFUL_INSERT_THRESHOLD

public final double SUCCESSFUL_INSERT_THRESHOLD

DESCRIBE THE FIELD

endpoint

protected Endpoint endpoint

DESCRIBE THE FIELD

storage

protected StorageManager storage

DESCRIBE THE FIELD

trash

protected StorageManager trash

DESCRIBE THE FIELD

backup

protected Cache backup

DESCRIBE THE FIELD

replicationFactor

protected int replicationFactor

DESCRIBE THE FIELD

replicaManager

protected ReplicationManager replicaManager

DESCRIBE THE FIELD

policy

protected PastPolicy policy

DESCRIBE THE FIELD

factory

protected IdFactory factory

DESCRIBE THE FIELD

instance

protected java.lang.String instance

DESCRIBE THE FIELD

inserts

public int inserts

DESCRIBE THE FIELD

lookups

public int lookups

DESCRIBE THE FIELD

fetchHandles

public int fetchHandles

DESCRIBE THE FIELD

other

public int other

DESCRIBE THE FIELD

environment

protected Environment environment

DESCRIBE THE FIELD

logger

protected Logger logger

DESCRIBE THE FIELD

Constructor Detail

PastImpl

public PastImpl(Node node,
                StorageManager manager,
                int replicas,
                java.lang.String instance)

Constructor for Past, using the default policy

Parameters:

node - The node below this Past implementation

manager - The storage manager to be used by Past

replicas - The number of object replicas

instance - The unique instance name of this Past

PastImpl

public PastImpl(Node node,
                StorageManager manager,
                int replicas,
                java.lang.String instance,
                PastPolicy policy)

Constructor for Past

Parameters:

node - The node below this Past implementation

manager - The storage manager to be used by Past

replicas - The number of object replicas

instance - The unique instance name of this Past

policy - DESCRIBE THE PARAMETER

PastImpl

public PastImpl(Node node,
                StorageManager manager,
                Cache backup,
                int replicas,
                java.lang.String instance,
                PastPolicy policy,
                StorageManager trash)

Constructor for Past

Parameters:

node - The node below this Past implementation

manager - The storage manager to be used by Past

replicas - The number of object replicas

instance - The unique instance name of this Past

backup - DESCRIBE THE PARAMETER

policy - DESCRIBE THE PARAMETER

trash - DESCRIBE THE PARAMETER

Method Detail

getEnvironment

public Environment getEnvironment()

Gets the Environment attribute of the PastImpl object

Specified by:

getEnvironment in interface Past

Returns:

The Environment value

getOutstandingMessages

public Continuation[] getOutstandingMessages()

Returns of the outstanding messages. This is a DEBUGGING method ONLY!

Returns:

The list of all the outstanding messages

getEndpoint

public Endpoint getEndpoint()

Returns the endpoint associated with the Past - ONLY FOR TESTING - DO NOT USE

Returns:

The endpoint

getUID

protected int getUID()

Returns a new uid for a message

Returns:

A new id

getResponseContinuation

protected Continuation getResponseContinuation(PastMessage msg)

Returns a continuation which will respond to the given message.

Parameters:

msg - DESCRIBE THE PARAMETER

Returns:

A new id

getHandles

protected void getHandles(Id id,
                          int max,
                          Continuation command)

Internal method which returns the handles to an object. It first checks to see if the handles can be determined locally, and if so, returns. Otherwise, it sends a LookupHandles messsage out to find out the nodes.

Parameters:

id - The id to fetch the handles for

max - The maximum number of handles to return

command - The command to call with the result (NodeHandle[])

getLocalNodeHandle

public NodeHandle getLocalNodeHandle()

get the nodeHandle of the local Past node

Specified by:

getLocalNodeHandle in interface Past

Returns:

the nodehandle

getReplicationFactor

public int getReplicationFactor()

Returns the number of replicas used in this Past

Specified by:

getReplicationFactor in interface Past

Returns:

the number of replicas for each object

getReplication

public Replication getReplication()

Returns the replica manager for this Past instance. Should *ONLY* be used for testing. Messing with this will cause unknown behavior.

Returns:

This Past's replica manager

getStorageManager

public StorageManager getStorageManager()

Returns this Past's storage manager. Should *ONLY* be used for testing. Messing with this will cause unknown behavior.

Returns:

This Past's storage manager.

getInstance

public java.lang.String getInstance()

Gets the Instance attribute of the PastImpl object

Specified by:

getInstance in interface Past

Returns:

The Instance value

buildReplicationManager

protected ReplicationManager buildReplicationManager(Node node,
                                                     java.lang.String instance)

Internal method which builds the replication manager. Can be overridden by subclasses.

Parameters:

node - The node to base the RM off of

instance - The instance name to use

Returns:

The replication manager, ready for use

sendRequest

protected void sendRequest(Id id,
                           PastMessage message,
                           Continuation command)

Sends a request message across the wire, and stores the appropriate continuation.

Parameters:

id - The destination id

message - The message to send.

command - The command to run once a result is received

sendRequest

protected void sendRequest(NodeHandle handle,
                           PastMessage message,
                           Continuation command)

Sends a request message across the wire, and stores the appropriate continuation.

Parameters:

handle - The node handle to send directly too

message - The message to send.

command - The command to run once a result is received

sendRequest

protected void sendRequest(Id id,
                           PastMessage message,
                           NodeHandle hint,
                           Continuation command)

Sends a request message across the wire, and stores the appropriate continuation. Sends the message using the provided handle as a hint.

Parameters:

id - The destination id

message - The message to send.

command - The command to run once a result is received

hint - DESCRIBE THE PARAMETER

cache

public void cache(PastContent content,
                  Continuation command)

Method which inserts the given object into the cache

Parameters:

content - The content to cache

command - The command to run once done

doInsert

protected void doInsert(Id id,
                        PastImpl.MessageBuilder builder,
                        Continuation command)

Internal method which actually performs an insert for a given object. Here so that subclasses can override the types of insert messages which are sent across the wire.

Parameters:

builder - The object which builds the messages

command - The command to call once done

id - DESCRIBE THE PARAMETER

insert

public void insert(PastContent obj,
                   Continuation command)

Inserts an object with the given ID into this instance of Past. Asynchronously returns a PastException to command, if the operation was unsuccessful. If the operation was successful, a Boolean[] is returned representing the responses from each of the replicas which inserted the object.

Specified by:

insert in interface Past

Parameters:

obj - the object to be inserted

command - Command to be performed when the result is received

lookup

public void lookup(Id id,
                   Continuation command)

Retrieves the object stored in this instance of Past with the given ID. Asynchronously returns a PastContent object as the result to the provided Continuation, or a PastException. This method is provided for convenience; its effect is identical to a lookupHandles() and a subsequent fetch() to the handle that is nearest in the network. The client must authenticate the object. In case of failure, an alternate replica of the object can be obtained via lookupHandles() and fetch(). This method is not safe if the object is immutable and storage nodes are not trusted. In this case, clients should used the lookUpHandles method to obtains the handles of all primary replicas and determine which replica is fresh in an application-specific manner.

Specified by:

lookup in interface Past

Parameters:

id - the key to be queried

command - Command to be performed when the result is received

lookup

public void lookup(Id id,
                   boolean cache,
                   Continuation command)

Method which performs the same as lookup(), but allows the callee to specify if the data should be cached.

Specified by:

lookup in interface Past

Parameters:

id - the key to be queried

cache - Whether or not the data should be cached

command - Command to be performed when the result is received

lookupHandles

public void lookupHandles(Id id,
                          int max,
                          Continuation command)

Retrieves the handles of up to max replicas of the object stored in this instance of Past with the given ID. Asynchronously returns an array of PastContentHandles as the result to the provided Continuation, or a PastException. Each replica handle is obtained from a different primary storage root for the the given key. If max exceeds the replication factor r of this Past instance, only r replicas are returned. This method will return a PastContentHandle[] array containing all of the handles.

Specified by:

lookupHandles in interface Past

Parameters:

id - the key to be queried

max - the maximal number of replicas requested

command - Command to be performed when the result is received

lookupHandle

public void lookupHandle(Id id,
                         NodeHandle handle,
                         Continuation command)

Retrieves the handle for the given object stored on the requested node. Asynchronously returns a PostContentHandle (or null) to the provided continuation.

Specified by:

lookupHandle in interface Past

Parameters:

id - the key to be queried

handle - The node on which the handle is requested

command - Command to be performed when the result is received

fetch

public void fetch(PastContentHandle handle,
                  Continuation command)

Retrieves the object associated with a given content handle. Asynchronously returns a PastContent object as the result to the provided Continuation, or a PastException. The client must authenticate the object. In case of failure, an alternate replica can be obtained using a different handle obtained via lookupHandles().

Specified by:

fetch in interface Past

Parameters:

command - Command to be performed when the result is received

handle - DESCRIBE THE PARAMETER

forward

public boolean forward(RouteMessage message)

This method is invoked on applications when the underlying node is about to forward the given message with the provided target to the specified next hop. Applications can change the contents of the message, specify a different nextHop (through re-routing), or completely terminate the message.

Specified by:

forward in interface Application

Parameters:

message - The message being sent, containing an internal message along with a destination key and nodeHandle next hop.

Returns:

Whether or not to forward the message further

deliver

public void deliver(Id id,
                    Message message)

This method is called on the application at the destination node for the given id.

Specified by:

deliver in interface Application

Parameters:

id - The destination id of the message

message - The message being sent

update

public void update(NodeHandle handle,
                   boolean joined)

This method is invoked to inform the application that the given node has either joined or left the neighbor set of the local node, as the set would be returned by the neighborSet call.

Specified by:

update in interface Application

Parameters:

handle - The handle that has joined/left

joined - Whether the node has joined or left

fetch

public void fetch(Id id,
                  NodeHandle hint,
                  Continuation command)

This upcall is invoked to tell the client to fetch the given id, and to call the given command with the boolean result once the fetch is completed. The client *MUST* call the command at some point in the future, as the manager waits for the command to return before continuing.

Specified by:

fetch in interface ReplicationManagerClient

Parameters:

id - The id to fetch

hint - DESCRIBE THE PARAMETER

command - DESCRIBE THE PARAMETER

remove

public void remove(Id id,
                   Continuation command)

This upcall is to notify the client that the given id can be safely removed from the storage. The client may choose to perform advanced behavior, such as caching the object, or may simply delete it.

Specified by:

remove in interface ReplicationManagerClient

Parameters:

id - The id to remove

command - DESCRIBE THE PARAMETER

scan

public IdSet scan(IdRange range)

This upcall should return the set of keys that the application currently stores in this range. Should return a empty IdSet (not null), in the case that no keys belong to this range.

Specified by:

scan in interface ReplicationManagerClient

Parameters:

range - the requested range

Returns:

DESCRIBE THE RETURN VALUE

scan

public IdSet scan()

This upcall should return the set of keys that the application currently stores. Should return a empty IdSet (not null), in the case that no keys belong to this range.

Returns:

DESCRIBE THE RETURN VALUE

exists

public boolean exists(Id id)

This upcall should return whether or not the given id is currently stored by the client.

Specified by:

exists in interface ReplicationManagerClient

Parameters:

id - The id in question

Returns:

Whether or not the id exists

existsInOverlay

public void existsInOverlay(Id id,
                            Continuation command)

DESCRIBE THE METHOD

Specified by:

existsInOverlay in interface ReplicationManagerClient

Parameters:

id - DESCRIBE THE PARAMETER

command - DESCRIBE THE PARAMETER

reInsert

public void reInsert(Id id,
                     Continuation command)

DESCRIBE THE METHOD

Specified by:

reInsert in interface ReplicationManagerClient

Parameters:

id - DESCRIBE THE PARAMETER

command - DESCRIBE THE PARAMETER