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1. Java Sockets

)Echo service

Java 4.5 4.6

(www.cdk5.net/ipc)

echo TCP streams.

M javac command line

client (TCPClient.java) server (TCPServer.java).

server client.

:

java TCPServer

java TCPClient Hello SDY50 Tomos Blocalhost

server IP

port number / .

) Knock KncokWhos there?

Knock Kncok Whos there

(http://en.wikipedia.org/wiki/Knock-knock_joke)

- Java sockets.

To ( )

(). :

: Knock, knock!

: Who's there?

: (.. Atch)

: ; (.. Atch who?)

: (..Bless you!)

()

.

, ,

http://www.cdk5.net/ipchttp://www.cdk5.net/ipchttp://www.cdk5.net/ipchttp://en.wikipedia.org/wiki/Knock-knock_jokehttp://en.wikipedia.org/wiki/Knock-knock_jokehttp://en.wikipedia.org/wiki/Knock-knock_jokehttp://en.wikipedia.org/wiki/Knock-knock_jokehttp://www.cdk5.net/ipc

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Bye. .

.

, Client,

TCPClient . Client

( {localhost, 5050})

.

Client socket server

socket / Java, streams

(.. BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in))

While( socket stream != null)

Begin

Bye. to loop

socket stream

EndWhile

KKServer Protocol.

Server

.

KKServer

listening socket While(true)

Begin

socket accept

I/O Java, streams

Protocol

output = processInput(null) // Protocol

(output)

While (input = socket stream != null)

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Begin

output = processInput(input)

(output)

output = Bye. to loop

EndWhile

EndWhile

. H

processInput Protocol.

( 1).

(input)

(output)

.

AWAIT

KNOCK_

KNOCK_

SENT

NAME_

SENT

[input==null]/

outpout="Knock! Knock!"

[input=="Who's there?"]/

outpout=names[currentRound]

[input!="Who's there?"]/

outpout= +"Knock! Knock!"

MORE

[input==names[currentRound]+" who?"]/

outpout=punch_line[currentRound] +

"Want more? (y/n)"

[input!=names[currentRound]+"who?"]/

outpout=+"Knock!Knock!"

[input=="y

"]/

outpout="K

nock!Kno

ck!"

currentRo

und+=%M

AX

[input!="y"]/outpout="Bye."

1.

:

private String[] names = { "You", "DNT", "Atch", "Who", "Who" };

private String[] punch_line = { "Did you call?",

"Your DeNTist! I wont hurt you!",

"Bless you!",

"Is there an owl in here?",

"Is there an echo in here?" };

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http://joke5.co.uk/joke/Category:Knock_Knock_Jokes

:

JAVA API TCP streams

Java.

1 KKProtocol.

:

.

, (threads)

.

:

KKServer threads

While(true)

Begin

thread

EndWhile

To thread

(Server).

.

2. Distributed Objects and Remote Invocation

(interface) Election :

vote: , (string)

(integer).

.

result:

.

http://joke5.co.uk/joke/Category:Knock_Knock_Jokeshttp://joke5.co.uk/joke/Category:Knock_Knock_Jokeshttp://joke5.co.uk/joke/Category:Knock_Knock_Jokes

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:

) input output;

) Election Java RMI.

) Election

.

Election (Maybe invocation, At-Least-OnceInvocation, At-Most-Once Invocation);

) Election

.

) Election

.

).

3.

(threads)

) threads, ,

;

) file server caching (hit ratio)

80%. sever 5 ms CPU time,

caching , 15 ms / .

server (

/sec), :i) server (single-threaded)

ii) o server -

iii) server

4.

web-based .

.

:

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(entry ticket) (

)

(

)

( ,

, , ,),

.

,

(web service provider)

.

5.

Pastry

(P2P) ,

(overlay routing) Pastry,

b=4 ( GUIDs) L=8 . GUID:

65a1fc D: e232fc, :

GUIDs 4

; ( ?)

;

( Figure 10.6 Distributed

Systems)