Roschelle Updated

8/9/2019 Roschelle Updated

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Season of mists and mellowfruitfulness ,


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Agenda

#ostly this$


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Agenda

And this$


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Agenda

And this$


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About your s!ea%er

& ' b a r uc hg i t h u b (c o m ) ' b a r u c h

lin%d(in)'baruch

stac%over*ow(com)users)+ - .


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What 0rog1


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What 0rog1


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What 0rog1


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What 0rog1


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SERVE BINARIES FOR A L


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CONCURRENT DOWNLOAD

Y U NO SUPPORT THEM?!


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2e3uirements

4 !arallel 5le 6ownloads

4 arallel 5le !arts4 interru!t)!ause)resume

4 rogress events4 Chec%sums caching


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9uc%y day$ 6ownload managerwritten in 'ava:


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ONE DOES NOT SIMPLY

EMBED JDM


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9et;s loo% if we can use it:

t;s an a!!, not a lib


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WANT CONCURRENT DOW

WRITE IT YOURSELF


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WHY WONT YOU JUST

USE URLCONNECTION?


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"ava(net(urlconnection

/( Bloc%ing streams


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What we;re loo%ing for


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What is >T going to ta%e


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Welcome to the reactor


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4 !attern for lightweight

concurrency4 Event driven

4 Threads reuse

4 Dses non bloc%ing >o


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riginal !attern

htt!$))www(dre(vanderbilt(edu)Fschmidt) 60)reactor siemens(!df


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Guess the author by thediagram

htt!$))gee(cs(oswego(edu)dl)c!'


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In Java,Reactor means

NIO


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Selector as a multi!le er


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"ava version 2egistering

SocketChannel channel=SocketChannel.open();

socketChannel.connect(new

InetSocketAddress("http://remote.com", 80));

...Selector selector = Selector.open();

channel.configureBlocking(false);

SelectionKey k =


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"ava version 6is!atcher

while (!Thread.interrupted()) {

selector.select() ;

Set selected =selector.selectedKeys();

Iterator it =selected.iterator();

while (it.hasNext()) SelectionKey k = (SelectionKey)(it.next();

( (Runnable)


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Handling reactor events is com!le

4=eed to maintain state

4Bu@ering 4 assemblingchun%s

4Coordinating async events


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HTTP NIO FRAMWORKS

DO THE HEAVY LIFTING


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=io libraries

4#ost of them are servers4=etty, griIIly, etc(

4A!ache #ina

4A!ache HTT com!onentsasyncclient

4=ing htt! client


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4Client and server nio

library4Evolved from netty49atest release ctober

-


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=io libraries

4#ost of them are servers4=etty, griIIly, etc

4A!ache #ina

4A!ache HTT com!onentsasyncclient

4=ing htt! client


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=ing;s async htt! client


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try ?AsyncHtt!Client asyncHtt!Client J newAsyncHtt!Client? 9istenable0utureL2es!onseM future J

asyncHtt!Client(!re!areGet? "http://oss.jfrog.org/api/system/ping" (e ecute? new AsyncCom!letionHandlerL2es!onseM? & verride public 2es!onse onCom!leted?2es!onseres!onse System( out (!rintln?res!onse(get2es!onseBody?

N return res!onse N

O & verride public void onThrowable?Throwable t t(!rintStac%Trace? N O


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HAC Conce!ts

42e3uest !roducer4

2es!onse consumer

try (CloseableHttpAsyncClient asyncHttpClient = HttpAsyncClients. createDefault ()) {


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asyncHttpClient.start();Future future = asyncHttpClient.execute(

HttpAsyncMethods.create et("http://oss.jfrog.org/api/system/ping" )!new AsyncByteConsumer() {

"#$errideprotected void onResponseRecei$ed(final HttpResponse response) {

%yste&.out .println(response.'et%tatus ine().'etReason hrase());*

"#$errideprotected void onByteReceived(final Char+u,,er bu,! final -#Control ioctrl) { *

"#$errideprotected void releaseResources() { *

"#$errideprotected HttpResponse buildResult( final HttpContext context) {return (HttpResponse) context.'etAttribute( "http.response" );

*

*! null );

HttpResponse response = future.get() ;*


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Choosing between ning and htt!asyncclient


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PAll !roblems in com!uterscience can be solved byanother level ofindirectionP 6avidWheeler


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URL ENCODING?


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Question:

What;s

wrongwith the

followingcode1


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public static StringencodeDrl?String urlStr D29Encoder( encode ?urlStr, "UTF- " N

(((O


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6ecoded D29s cannot bere encoded to the same form

http //exa& ple.co& /01uery= a2 b= = c

Cannot be decoded bac4 a,ter it 5 asencoded

http //exa& ple.co& /01uery= a6 78b= = c

6 t
http://example.com/?query=a&b==chttp://example.com/?query=a&b==chttp://example.com/?query=a&b==chttp://example.com/?query=a&b==chttp://example.com/?query=a&b==chttp://example.com/?query=a&b==chttp://example.com/?query=a&b==c


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6on;t use 'ava(net(D29Encoder

7Dtility class for HT#9 formencoding( This class contains static

methods for converting a String tothe application/x-www-form-urlencoded #>#E format(

0or more information about HT#9form encoding, consult the HT#9s!eci5cation(8


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AHC Alternatives

or'.apache.http.client.utils.9 R-+uilder

or'.apache.http.client.utils.9 R :ncoded9 tils


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Question:

How do >

close asoc%et

correctly1

H h d i b l


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How hard can it be to close asoc%et1


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The art of soc%et closing

htt!$))www(safariboo%sonline(com)library)view)htt! the

Half closed$ no new


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Half closed$ no newcustomers

=ever bloc% in soc%et


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=ever bloc% in soc%etclose?

The other side e !ects

you to clean u! nicely >t will give u! on time

out You will wait ?forever

I ALWAYS CLOSE


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I ALWAYS CLOSE

CONNECTIONS

AND WHEN I DO IT, I USE

TRY-WITH-RESOURCES


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2emember1


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4 W i ! 5l


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4 Write to se!arate 5les,

combine on 5nish4 Write to same 5le,

see%ing to the right!osition

WHY WONT YOU JUST U


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WHY WON T YOU JUST U

JAVA IO RANDOMACCESSFIL


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DSE 0ileChannel

>m!lements %ee4able+yteChannel

a$a.nio.channels. ileC hannel < w rite( a$a.nio.+yte+u,, er src! lon'position )


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download !rogress trac%ing

!ersistent 0ile rogress>nfo Save the total siIe, shanfo

0ile art rogress>nfo

U


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0ile 9oc%ing


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0ile loc%ing 9evels

4V# level4 S level


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S level 0ile loc%ing

#ulti!le downloader instanceswriting to the same 5le

=eeded for writing$ artial download 5le ersistent download !rogress

S 9evel 0ile 9oc%ing


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File oc4 loc4 = ,i leChannel.try oc4(); // ! on"shared ( ! on'.M A>?@A 9 :!

false )if (loc4 = = null ) { throw new# $erlappin'File oc4:xception();

* return loc4;*

S 9evel 0ile 9oc%ing E clusive

S 9evel 0ile 9oc%ing 4


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private File oc4 loc4(FileChannel ,i leChannel) throw s-# :xception {

File oc4 loc4 = ,i leChannel.try oc4( on'. M A X _VA LU EB! B! false );

if (loc4 = = null ) { throw new # $erlappin'File oc4:xception();

* return loc4;*

S 9evel 0ile 9oc%ing 4Advisory e clusive

WT01:


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V# 9evel 0ile 9oc%ing

WHY DO YOU NEEDLOCKS

IF YOU WRITE TO

DIFFERENT PARTS OF


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V# 9evel 0ile 9oc%ing

4 revent same V# threads writing tothe 5le when we started closing it

4Closing se3uence$42elease 5le loc%s4Close channels42ename a 5le to it s 5nal name

?remove (!art4Erase !rogress info


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V# 9evel 0ile 9oc%ingReentrantRead rite oc4.Read oc4 w rite$o ile%oc& = r5 l.read oc4();ReentrantRead rite oc4. rite oc4 close ile%oc& =r5 l.5 rite oc4();

public $oid close() thro5 s -# :xception { this. close ile%oc&.loc& ();*

public int 5 rite(int part-ndex! +yte+u,, er bu,) { i, (Dthis. w rite$o ile%oc&.try%oc& ()) { thro5 ne5 -lle'al%tate:xception(EFile is bein'closedE); *


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What;s ne t1


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htt!)-

4 #ostly standardiIing Google s s!dy4 Header com!ression

4 multi!le ing4 rioritiIation4 Server !ush

4 n the way clear some stu@ 4 E(g( com!ressed content length


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Ease the load


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9in%s:

2T0#$ 20C -R

h
http://www.w3.org/Protocols/rfc2616http://www.amazon.com/HTTP-The-Definitive-Guide-Guides/dp/1565925092http://www.safaribooksonline.com/library/view/http-the-definitive/1565925092/http://jeewanthad.blogspot.co.il/2013/02/reactor-pattern-explained-part-1.htmlhttp://gee.cs.oswego.edu/dl/cpjslides/nio.pdfhttp://gee.cs.oswego.edu/dl/cpjslides/nio.pdfhttp://jeewanthad.blogspot.co.il/2013/02/reactor-pattern-explained-part-1.htmlhttp://www.safaribooksonline.com/library/view/http-the-definitive/1565925092/http://www.amazon.com/HTTP-The-Definitive-Guide-Guides/dp/1565925092http://www.w3.org/Protocols/rfc2616


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=o, Than% you:


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A Quic% Tourof Logos

The 9ogical A!!eal


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So what e actly is logic1 Whocares1>nformally, logic is about saying things that ma&esense. You can thin% of it in that way if you li%e(

7>t s !retty sunny today, so you should wear sunscreen(8

0ormally, logic is the art of arguing 4not li%e a 5ght or debate, but by

using the information we already%now to draw new and usefulconclusions(7>f it s sunny today, you should wear sunscreen(

>ndeed it is sunny today( Therefore, you should wear sunscreen(8


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7But wait( That 'ust loo%ed li%e the

e act same thing you said before,you hac%( 8

ell, yes( But that s how an argument loo%s in starm: You can brea% down any argument into thisat ma%es it easier to thin% about(

>f it s sunny today, you should wear sunscre

>t is sunny today( XXXXXXXXXXXXXXXXXXXXXXXXXXXX

Therefore, you should wear sunscreen(

remises)givens

Conclusion? remises always come 5rst, and the conclusion always come


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How about a more com!leargument1

t also has seeds(

/( >f a fruit is fuIIy, it s either a %iwi or a !each(+( eaches have a !itN they don t have seeds(

.( So the fruit can t be a !each(R( So the fruit must be a %iwi(

Which of the above sentences is a conclusion


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How about a more com!leargument1

t also has seeds(

/( >f a fruit is fuIIy, it s either a %iwi or a !each(+( eaches have a !itN they don t have seeds(

.( So the fruit can t be a !each(R( So the fruit must be a %iwi(

Good logic lets us cobble together lots of di@erent !ieces of information, and tell from

them what s probably or defnitely true.


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But what counts as 7good logic81

Some !eo!le have fallen o@ cli@s and lived(

erefore, if > 'um! o@ this cli@, > will de5nitely be

7Comeon(Whatcould!ossibly


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Some !eo!le have fallen o@ cli@s and lived(

erefore, if > 'um! o@ this cli@, > will de5nitely be

his argument is wea%( Although the !remise is ts easy to thin% of ways ?very !ainful ways that

nclusion could be false( The easiest way to s!ogic is to do 'ust that$ try to thin% of another wa

hiloso!hers call these counterexamples (


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9et s loo% at two %inds ofarguments(

'. 6eductive reasoning$ All interns can breathe 5re( Sohili! can breathe 5re(

>s there a !iece of the !uIIle missing1


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9et s loo% at two %inds of arguments('. 6eductive reasoning$

All interns can breathe 5re( hili!is an intern( So hili! canbreathe 5re(

ometimes you may encounter 7hidden8 statemnd ideas, which the writer snea%s in but doesn ty outright(


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9et s loo% at two %inds of arguments((. >nductive reasoning$

> touched a stove and it burned me( > did this

5fty times, and the same thing ha!!ened( Sothene t time > touch the stove, it will burn me(

Are the !remises true1>f so, then the conclusion s

probably true( There mightstill be e ce!tions(

9>KE WHAT1


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How is this useful to me1

9i%e #r( #organ said, the ability toma%e strong logical arguments willbecome more and more im!ortantlater on in high school and college(

athos and ethos are still valuable:But your audience will be a lot betterat 3uestioning them( 9ogos is handybecause, if you use it well, it can t


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What time is it1Adven wait, no( Activity time:

air o@ into grou!s of four( Each grou! will receive an e amf a !oor argument ?these may be either inductive or deduc

ith your grou!, you will have . minutes to try to come u!ne countere)ample one way in which the argumentould be wrong, even if the !remises are de5nitely true(

o%e it full of holes:lso, choose a grou! re!resentative to tell us your reasonin

>t s K to imagine unli%ely or weird e !lanationsN

on t be afraid to thin% outside the bo (


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*ohn +eats


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PTo ,utumn P is a !oem by English2omantic !oet "ohn Keats ?/< ctober

< . 4 -/ 0ebruary < -< (
http://en.wikipedia.org/wiki/Poetryhttp://en.wikipedia.org/wiki/Romanticismhttp://en.wikipedia.org/wiki/John_Keatshttp://en.wikipedia.org/wiki/John_Keatshttp://en.wikipedia.org/wiki/Romanticismhttp://en.wikipedia.org/wiki/Poetry


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PTo AutumnP is a !oem of three stanIas, each of elevenlines( Written in < < , the structure is that of an odal hymn, having three clearly de5ned sections corres!onding to the

Classical divisions of stro!he , antistro!he , and e!ode
http://en.wikipedia.org/wiki/Ode#English_odehttp://en.wikipedia.org/wiki/Ode#English_odehttp://en.wikipedia.org/wiki/Strophehttp://en.wikipedia.org/wiki/Antistrophehttp://en.wikipedia.org/wiki/Epodehttp://en.wikipedia.org/wiki/Epodehttp://en.wikipedia.org/wiki/Antistrophehttp://en.wikipedia.org/wiki/Strophehttp://en.wikipedia.org/wiki/Ode#English_odehttp://en.wikipedia.org/wiki/Ode#English_ode


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The imagery is richly achieved throughthe !ersoni5cation of Autumn
http://en.wikipedia.org/wiki/Personificationhttp://en.wikipedia.org/wiki/Personification


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!oem

Season of mists and mellow


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fruitfulness,


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lose bosom-friend of thematuring sun


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ith fruit the vines that roundthe thatch-eves run


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To bend with a!!les the moss d


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cottage trees ,

,nd $ll all fruit withripeness to the core


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ripeness to the core

To swell the gourd, and !lum! thehaIel shells


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haIel shells

With a sweet %ernelN to set


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budding more,

And still more, later *owers for


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the bees,

Dntil they thin% warm days will


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never cease,


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Who hath not seen thee oft amidh


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thy store 1

Sometimes whoever see%sb d 5 d


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abroad may 5nd

Thee sitting careless on a granary


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*oor,

Thy hair soft lifted by thed


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winnowing wind


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6rowsed with the fume of !o!!ies, whileth h %


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thy hoo%


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And sometimes li%e a gleaner thoud % !


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dost %ee!

Steady thy laden head across ab %N


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broo%N

3patient loo&3


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Thou watchest the last ooIings,hours by hours(


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hours by hours(

Where are the songs of S!ring1 Ay,where are they1


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where are they1

Thin% not of them, thou hast thyi t [


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music too,[

While barrZd clouds bloom the softdying day


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dying day

And touch the stubble !lains withrosy hueN


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en n a wa u c o r e smagnats mourn


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-sallows3 borne aloft


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r sin&ing as the light windives or dies


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ives or diessin%ing


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edge cric%ets singN and now withreble soft


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reble soft

The redbreast whistles from a gardencroftN


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An gat er ng swa ows tw tter n t es%ies(


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lose bosom-friend of thematuring sun

onspiring with him how to load andbless


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ith fruit the vines that round the thatch-eves run


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To bend with a!!les the moss d cottagetrees


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trees ,

,nd $ll all fruit with ripeness to the core


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To swell the gourd, and !lum! thehaIel shells


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With a sweet %ernelN to set buddingmore


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more,

And still more, later *owers for thebees


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bees,

Dntil they thin% warm days will nevercease,


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cease,

For 0ummer has o1er-brimm1d theirclammy cells.


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Who hath not seen thee oft amid thystore 1


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store 1

Sometimes whoever see%s abroadmay 5nd


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Thee sitting careless on a granary*oor,


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oor,

Thy hair soft lifted by the winnowingwind


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w d

r on a half rea!;d furrow soundaslee!,


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,

6rowsed with the fume of !o!!ies, while thyhoo%


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S!ares the ne t swath and all itstwinZd *owers$


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And sometimes li%e a gleaner thoudost %ee!


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Steady thy laden head across abroo%N


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- 3patient loo&3


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Thou watchest the last ooIings, hoursby hours(


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Where are the songs of S!ring1 Ay, whereare they1


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Thin% not of them, thou hast thy musictoo,[


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While barrZd clouds bloom the softdying day


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And touch the stubble !lains withrosy hueN


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en n a wa u c o r e sma gna smourn


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r sin&ing as the light windives or dies


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sin%ing

And full grown lambs loud bleat from hillybournN


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edge cric%ets singN and now with trebloft


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The redbreast whistles from a gardencroftN


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Element 0ormulation by VirtualWor%


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Dse virtual wor% to derive elementsti@ness matri based on assumeddis!lacements

rinci!le of virtual wor% states that if ageneral structure that is in e3uilibriumwith its a!!lied forces deforms due to aset of small com!atible virtual

dis!lacements, the virtual wor% done ise3ual to its virtual strain energy ofinternal stresses(


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At element level, Ue J ' e Ue J virtual strain energy of internal

stresses

' e J virtual wor% of e ternal forcesacting through virtual dis!lacements


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We now assume a sim!le dis!lacementfunction to de5ne the dis!lacement ofevery material !oint in the element(

Dsually use low order !olynomials Here

u J a < \ a - x u is a ial dis!lacement a


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The constants are found by im!osingthe %nown nodal dis!lacements u i, u ( at nodes i and (

u i ) a < * a - x iu ( ) a < * a - x (

u i, u ( are nodal dis!lacements x i, ( are nodal coordinates


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letting x i J , x ( J L, we get a < J u i a - J ? u ( u i +)L

We can write

]=^ J matri of element sha!e functionsor inter!olation functions

d O J nodal dis!lacements

u x

L x L

u

u d

i

j

= =1 [ ]{ } N

[ ] [ ]N N N=


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=


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Strain is given by

where ]B^ is a matri relating strainto nodal dis!lacement ?matri of

derivatives of sha!e function

[ ] [ ]

du d[N]{d} [B]{d}

dx dx1

B 1 1L

= = =

=


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=ow ) !, ) ) ! ]B^ d O E

Stress and strain are constant in amember

6e5ne internal virtual strain energyfor a set of virtual dis!lacements

d O to beT

e! " # d =


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- J virtual strain- J stress level at e3uilibrium d- J volume

Virtual wor% of nodal forces is ' e J d O# O

Then, virtual wor% is given by

( ) { } { }T Td$ d % =

Substituting and rearranging gives


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Substituting and rearranging gives

Canceling d O# gives ]%^ d OJ / Owhere

0or thermal !roblem

( ) ( )T ToT T T T T

o

[B]{ d} &[B]{d} & d { d} {% }

{ d} [B] &[B]{d}d { d} [B] & d$ { d} {% }

= = +

[ ] [ ] [ ]' B B= T V E dV

{ } { } o 1( % &) 1 = +

oT =


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for a truss we get

this formulation method also a!!liesto - d and / d elements

[ ]' =

EA

L

1 1

1 1

cedure for 6irect Sti@ness #ethod ?6is!lacement #eth

1. *is+retize into %inite elements, denti%y nodes, elements


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and num-er them in order.

2. *e$elop element sti%%ness matri+es [ e] %or all theelements.

/. )ssem-le element sti%%ness matri+es to 0et the 0lo-alsti%%ness matrix "[ ] [ e]#. The size o% o% 0lo-alsti%%ness matrix total d.o.% o% the stru+ture in+ludin0 at

-oundary nodes. )ssem-ly is done -y mat+hin0 element

displa+ement 3ith 0lo-al displa+ements. )lso de$elopappropriate %or+e $e+tor "-y addin0 element %or+e $e+tors#su+h that e4uation o% the type [ ] {u} {(} is o-tained.

5. )pply 'inemati+ -oundary +onditions. 6ithout applyin0

rocedure for 6irect Sti@ness #ethod


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)pp y y pp y -oundary +onditions, [ ] 3ill -e sin0ular. "minimumnum-er o% -oundary +onditions re4uired is to arrest 78i0idBody9 displa+ements#.

:. ;ol$e %or un'no3n displa+ements {u} " {u} [ ] n+e displa+ements are determined %ind

"a# rea+tions -y pi+'in0 up appropriate ro3s %rom thee4uation {(} [ ] {u}, "-# (ind element %or+es {%} [ e]{u e}, "+# &lement stresses 0i$en -y { e} [*][B]{u e}.


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1 2 3

F1 , u 1F2, u 2 F

3, u

3

Boundary Conditionsu

1=0, u

2=0

-A, 9, E A, 9, E


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[ ]2 ?2

)& ?2 2@1 ?1L

?1 1

=


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2eactions

{ } [ ]

{ } [ ]

1

/

A)& PL 2P

( 2 ?2 A 1L /)& /

A

A)& PL P

( A ?1 1 1L /)& /

A

= =

= =

Element 0orces

f f&lement 1


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A, 9, E

f < f -

-A, 9, E

A, 9, E

1 1

2 2

21

/2

% u1 ?12)&% ?1 1 uL

1 ?1 A 2p /2)& PL

?1 1 1 2p /L /)&&lement 2

u% 1 ?1)&u% ?1 1L

1 ?1)&

?1L

=

=

=

1 p /PL 1 A p //)&

=

2P/

2P/

P/

P/


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u < u - u - u /

[ ] [ ]1 2

&lement 1 &lement 2

1 1 1 1)& )&

1 1 1 1L L = =


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;tress in element 1


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1 11 1

2 2

5 22 1

2 22 2

/ /

5/ 2

u u1 1& &B &u uL L

u u 1.: A & 2.A 1A 2AAN mm

L 1:A;tress in element 2

u u1 1& &B &

u uL Lu u 1.2 1.:

& 2.A 1AL 1:A

= = = = =

= = =

= = 25AN mm

6irect Element 0ormulation


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truss element acts li%e < d s!ring l MM transverse dimensions !inned connection to other members

?only a ial loading ( usually constant cross section and

modulus of elasticity


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A J cross section area ! J modulus of elasticity L J length

k AE

L=


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Assume dis!lacements are muchsmaller than overall geometry vertical dis!lacements of horiIontal

member !roduce no vertical force Sti@ness matri is written in local

element coordinates aligned alongelement a is

want sti@ness matri for arbitraryorientation


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rotate coordinate systems usingrotation matri ]2^ dis!lacement com!onents in global

coordinates are related todis!lacement com!onents in localcoordinates by d OJ]2^ d O d O J dis!lacement in global

coordinates d;O J dis!lacement in local elementcoordinates

AE

y

i jui ui

vi v j

pi

P j

i j


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L

x

i u ip i

st

' A

1 +olumn '

A

=

rd

'

A/ +olumn

'

A

=

A


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th A5 +olumnA

A

=

nd

A

A2 +olumn

A

A

=


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start with member on x a is, elemente3uations are

or %;O d;OJ f;O =ote that y e3uations are all Iero

i i

i i

C C

C C

u D p D' A ' A$ D 4 DA A A A

u D pD' A ' A$ D 4 DA A A A

=

xy yp j u j

v j

j


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pi ui

x

i

vi

i i i i i i

i i i i i i

at node iu D u +os" # $ sin" # p D p +os" # 4 sin" #$ D u sin" # $ +os" # 4 D 4 sin" # 4 +os" #

= + = + = + = +

At node i


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A similar matri can be obtained at node '

i i

i i

u D u+os sin$ D sin +os $

= i i

i i

pD p+os sin4 D sin +os 4

=

i i

i i

C C

C

u D u+os sin A A$ D $sin +os A Au D u A A +os sin

A A sin +os$ D

= C$


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#atri ]2^ is$+os sin

sin +os

+os sin

sin +os

A A

A A

A A

A A

A A

A A

A A

A A

=

c s

s c

c s

s c


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Similarly , force com!onents arerelated by O J ]2^ O 9ocal force dis!lacement relation is

]%;^ d;O J f;O global force dis!lacement relation is]%^]2^ d O J ]2^ O

using fact that ]2^

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