dd.db
Class HashStorageManager

java.lang.Object
  |
  +--bamboo.util.StandardStage
        |
        +--dd.db.HashStorageManager

All Implemented Interfaces:

EventHandlerIF, SingleThreadedEventHandlerIF

public class HashStorageManager

extends StandardStage

implements SingleThreadedEventHandlerIF

An inline/in memory database backed by java hashtables..

Data is stored on disk in a table with the following fields:

Bytes	Data
0-7	put time since the epoch (microseconds)
8-11	ttl interval after put time (seconds)
12-31	guid
32-51	data hash
52	whether this is a put (1) or remove (0)
53-	data

The data hash is needed to guarentee a consistent scan order and for removes. The primary key is bytes 0-52, and the secondary key is the guid concatenated with the data hash.

Version:

$Id: HashStorageManager.java,v 1.6 2004/05/28 17:45:39 hweather Exp $

Author:

Hakim Weatherspoon

Nested Class Summary

protected static class	HashStorageManager.EnqueueEvent EnqueueEvent is the event used by Classifier.dispatch_later(seda.sandStorm.api.QueueElementIF, long) to prevent StackOverflowError when the DataManager is creating a MerkleTree.
protected static class	HashStorageManager.GBGCont
protected static class	HashStorageManager.GBTCont
protected static class	HashStorageManager.IBGCont

Field Summary

static byte[]	MAX_HASH
static byte[]	MIN_HASH
static StorageManager.Key	MIN_KEY
protected static BigInteger	zero_guid

Fields inherited from class bamboo.util.StandardStage

acore, classifier, DEBUG, event_types, inb_msg_types, logger, my_node_id, my_sink, outb_msg_types, sim_running

Constructor Summary

HashStorageManager()

Method Summary

protected void	application_enqueue(SinkIF sink, QueueElementIF item) application_enqueue calls Classifier.dispatch_later(seda.sandStorm.api.QueueElementIF, long), even in simulation to prevent StackOverflowError when the DataManager is creating a MerkleTree.
protected void	do_get_by_guid(HashStorageManager.GBGCont cont, SinkIF comp_q, Object user_data)
protected void	do_get_by_time(HashStorageManager.GBTCont cont, SinkIF comp_q, Object user_data)
protected void	do_iterate_by_guid(HashStorageManager.IBGCont cont, SinkIF comp_q, Object user_data)
protected void	handle_discard_req(StorageManager.DiscardReq req)
protected void	handle_get_by_guid_cont(StorageManager.GetByGuidCont req)
protected void	handle_get_by_guid_req(StorageManager.GetByGuidReq req)
protected void	handle_get_by_key_req(StorageManager.GetByKeyReq req)
protected void	handle_get_by_time_cont(StorageManager.GetByTimeCont req)
protected void	handle_get_by_time_req(StorageManager.GetByTimeReq req)
protected void	handle_iterate_by_guid_cont(StorageManager.IterateByGuidCont req)
protected void	handle_iterate_by_guid_req(StorageManager.IterateByGuidReq req)
protected void	handle_put_req(StorageManager.PutReq req) handle_put_req does exactly that.
void	handleEvent(QueueElementIF item) Specified by seda.sandStorm.api.EventHandlerIF
void	init(ConfigDataIF config)
protected boolean	key_expired(StorageManager.Key k)
static void	main(String[] args)

Methods inherited from class bamboo.util.StandardStage

BUG, BUG, BUG, config_get_boolean, config_get_double, config_get_int, config_get_string, destroy, dispatch, enqueue, handleEvents, lookup_stage, now_ms, timer_ms

Methods inherited from class java.lang.Object

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

Field Detail

zero_guid

protected static BigInteger zero_guid

MIN_HASH

public static final byte[] MIN_HASH

MAX_HASH

public static final byte[] MAX_HASH

MIN_KEY

public static final StorageManager.Key MIN_KEY

Constructor Detail

HashStorageManager

public HashStorageManager()

Method Detail

init

public void init(ConfigDataIF config)
          throws Exception

Specified by:

init in interface EventHandlerIF

Overrides:

init in class StandardStage

Exception

handleEvent

public void handleEvent(QueueElementIF item)

Specified by seda.sandStorm.api.EventHandlerIF

Specified by:

handleEvent in interface EventHandlerIF

handle_put_req

protected void handle_put_req(StorageManager.PutReq req)

handle_put_req does exactly that. That is, there should be at most one put and one remove stored in the database for this (guid, data_hash) pair. We need to check for them first, then put this new datum in, and then return whichever existing datum it overrides, if any.

Parameters:

req - StorageManager.PutReq.

key_expired

protected boolean key_expired(StorageManager.Key k)

handle_get_by_key_req

protected void handle_get_by_key_req(StorageManager.GetByKeyReq req)

handle_iterate_by_guid_req

protected void handle_iterate_by_guid_req(StorageManager.IterateByGuidReq req)

handle_iterate_by_guid_cont

protected void handle_iterate_by_guid_cont(StorageManager.IterateByGuidCont req)

do_iterate_by_guid

protected void do_iterate_by_guid(HashStorageManager.IBGCont cont,
                                  SinkIF comp_q,
                                  Object user_data)

handle_get_by_guid_req

protected void handle_get_by_guid_req(StorageManager.GetByGuidReq req)

handle_get_by_guid_cont

protected void handle_get_by_guid_cont(StorageManager.GetByGuidCont req)

do_get_by_guid

protected void do_get_by_guid(HashStorageManager.GBGCont cont,
                              SinkIF comp_q,
                              Object user_data)

handle_get_by_time_req

protected void handle_get_by_time_req(StorageManager.GetByTimeReq req)

handle_get_by_time_cont

protected void handle_get_by_time_cont(StorageManager.GetByTimeCont req)

do_get_by_time

protected void do_get_by_time(HashStorageManager.GBTCont cont,
                              SinkIF comp_q,
                              Object user_data)

handle_discard_req

protected void handle_discard_req(StorageManager.DiscardReq req)

application_enqueue

protected void application_enqueue(SinkIF sink,
                                   QueueElementIF item)

application_enqueue calls Classifier.dispatch_later(seda.sandStorm.api.QueueElementIF, long), even in simulation to prevent StackOverflowError when the DataManager is creating a MerkleTree.

main

public static void main(String[] args)