edu.harvard.deas.hyperenc.vsat
Class PageServerNode

java.lang.Object
  java.lang.Thread
      edu.harvard.deas.hyperenc.vsat.PageServerNode

All Implemented Interfaces:

Runnable

public class PageServerNode
extends Thread

The PageServerNode represents a Page Server Node in the hyper-encryption system. It listens for page requests and responds to them. Each request consists of a 32-bit integer, the page request key. The PSN responds to a page request by sending back a 4096-byte page of random data; each page is served at most twice.

A PageServerNode is backed by a PageDatabase, which handles the details of page management. The PageServerNode itself receives requests and uses the contained request key to retrieve a page from the PageDatabase. It then sends this page back to the requester.

The request key is interpreted as a big-endian integer: the high byte comes first.

See Also:

PageDatabase

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

static int

DEFAULT_PSN_PORT The port on which the PSN listens for connections/requests.

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

PageServerNode()
Creates a new Page Server Node using the default port.

PageServerNode(int psn_port)
Creates a new Virtual Satellite node that listens for connections on psn_port.

Method Summary

boolean	isShutdown() Whether or not to shut down.
static void	main(String[] args) Creates a PSN and runs it until the process is killed.
void	run() The main thread of execution for the PSN.
void	shutdownNow() Shut down the server now.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PSN_PORT

public static final int DEFAULT_PSN_PORT

The port on which the PSN listens for connections/requests.

See Also:

Constant Field Values

Constructor Detail

PageServerNode

public PageServerNode()

Creates a new Page Server Node using the default port. Equivalent to PageServerNode(DEFAULT_PSN_PORT).

PageServerNode

public PageServerNode(int psn_port)

Creates a new Virtual Satellite node that listens for connections on psn_port. This does all of the network setup as well

Parameters:

psn_port - The port on which to listen for connections.

Method Detail

main

public static void main(String[] args)

Creates a PSN and runs it until the process is killed.

isShutdown

public boolean isShutdown()

Whether or not to shut down.

Returns:

Whether we have been told to shut down.

shutdownNow

public void shutdownNow()

Shut down the server now.

run

public void run()

The main thread of execution for the PSN. It listens for connections and processes any received requests. Loops until killed, for example by SIGTERM.

Specified by:

run in interface Runnable

Overrides:

run in class Thread