Component-Based Software Engineering
|
|
- Bruce Griffin
- 6 years ago
- Views:
Transcription
1 Component-Based Software Engineering More stuff on Threads Paul Krause Lecture 7 - Contents Basics of threads and synchronization Waiting - releasing locks Collection Plate example Choices when pausing execution Ice Cream Example Notify versus NotifyAll 1
2 Quick Reminder User requests document is printed and saved Word processor spools print job Word processor starts saving to hard drive User requests document is printed and saved A Better Solution Thread starts spooling print job User requests document is printed and saved Spawn threads to print and save Main thread waits until other threads are complete User gets control ready for next operation Thread starts saving document to hard drive 2
3 Basic concepts Synchronization enables a Java object to be locked for exclusive use by a thread A locked object is inaccessible to any thread other than the one that locked it So long as the other threads honour this Each object can keep track of the other threads that want exclusive access to it How to keep threads fighting over limited toys! Waiting This is not just a matter of notifying the JVM it can (but doesn t have to!) provide resource to other threads As with Thread.yield or Thread.sleep Calling myobject.wait will release myobject s lock Waiting is the process of getting (completely) out of the way when you can t be productive 3
4 CollectionPlate example Minister passes around a collection plate He waits until the collection has exceeded a certain amount While he is waiting, other people can modify the state of the collection plate By adding money to it Once the total collected exceeds a certain amount, the Minister takes back the plate Structure of Minister Class public class Minister { private CollectionPlate collectionplate = new CollectionPlate(); private class CollectionAcceptor extends Thread { private class CollectionChecker extends Thread { 4
5 CollectionPlate We will lock the instance of CollectionPlate whenever we access or modify its state private class CollectionPlate { int amount = 0; main method Start off a thread that is going to monitor the state of the collectionplate minister.new CollectionChecker().start(); Within the run method of the CollectionChecker, we Obtain the lock on collectionplate If the amount on the collectionplate is less than 100 we temporarily release the lock until we are notified by another thread of a change 5
6 CollectionChecker s run() synchronized (collectionplate) { while (collectionplate.amount < 100) { try { System.out.println("Waiting"); collectionplate.wait(); catch (InterruptedException ie) { ie.printstacktrace(); // getting past the while statement means that the // contribution goal has been met System.out.println("Thank you!"); More detail The CollectionChecker must have the lock for collectionplate before it calls wait() on it The CollectionChecker cannot proceed if there is less than 100 units on the plate So thecollectionchecker waits by releasing the lock on the collectionplate and waiting until another thread notifies it of a change in state to the latter If the amount is still < 100 it waits some more. Otherwise it says Thank you and terminates 6
7 What happens during a wait In the Minister case, several threads have been started up that can accept contributions: for (int i = 0; i < 6; i++ ) { minister.new CollectionAcceptor(20).start(); In turn, each will claim the lock on the collectionplate, add $20 and then notify the ministrr when it has finished CollectionAcceptor s run() synchronized (collectionplate) { int amount = collectionplate.amount + contribution; String msg = "Contributing: current amount: " + amount; System.out.println(msg); collectionplate.amount = amount; collectionplate.notify(); 7
8 The result In turn (why?) each instance of CollectionAcceptor obtains the lock on collectionplate $20 is then added to the collectionplate and the waiting class is notified when the lock is released again The CollectionAcceptor ( minister ) can resume execution and check the contents of the collectionplate An example run run-single: Waiting Contributing: current amount: 20 Waiting Contributing: current amount: 40 Waiting Contributing: current amount: 60 Waiting Contributing: current amount: 80 Waiting Contributing: current amount: 100 Thank you! Contributing: current amount: 120 8
9 In General If myobject.wait() is called by threada, then: threada temporarily releases the lock on myobject Execution of threada is suspended threada registers its interest in being notified after another thread has modified myobject Once notified, threada can resume execution having recovered the lock on myobject It is the designer s responsibility to ensure waiting objects are notified Pausing execution Maintain current locks Waiting for some event to occur, before completing the process of accessing or modifying a resource Release current locks Having completed business with a resource, this pause means the thread has finished its work for now 9
10 Other fun things with threads! Yielding Politely offering up your place the the queue Does not release locks Blocking A thread will block while it is waiting for a lock The JVM will automatically tranisition it to Runnable when the lock becomes available Sleeping Waits at least as long as the specified time Ice-cream man example We create a number of Children as customers of an IceCream man Each Child has an IceCreamDish that should be filled completely before the IceCream man serves another customer In the the application, the instance of IceCreamMan is declared static to ensure there is only one instance (is there another way of doing this?) The IceCreamMan s thread is set as a daemon thread - So? 10
11 Basic outline Start the IceCreamMan on a new thread Start three instances of Child, each on their own thread Each child will obtain a dish of ice cream and eat it Once all three children have eaten their ice cream, the main thread prints out a message and terminates What about icecreamman? Starting the icecreamman Remember icecreamman = new IceCreamMan() is a static property of Chil\ Hence (as far as Children are concerned) there is only one icecreamman In the main method: icecreamman.setdaemon(true); icecreamman.start(); 11
12 Getting the children going String[] names = {"Ricardo", "Paolo", "Maria"; Thread[] children = new Thread[names.length]; // create some child objects // create a thread for each child // get the Child threads started int counter = -1; for (String name : names) { Child child = new Child(name); children[++counter] = new Thread(child); children[counter].start(); What s the icecreamman doing? The icecreamman has a list of IceCreamDishes: private List<IceCreamDish> dishes = new ArrayList<IceCreamDish> (); If the list is not empty, he serves some ice cream, otherwise he sleeps for a bit to give the children a chance to add dishes 12
13 icecreamman.run() public void run() { while (true) { if (!dishes.isempty()) { serveicecream(); else { try { sleep(1000); catch(interruptedexception ie) { ie.printstacktrace(); The story so far The icecreamman is waiting for some dishes to fill Three children have been started, so what are they doing? Child.run() // add mydish to icecreamman.dishes icecreamman.requesticecream(mydish); // now try to eat mydish of ice cream eaticecream(); 13
14 Eating icecream public void eaticecream() { synchronized(mydish) { while (mydish.readytoeat == false) { try { System.out.println(name + msg); mydish.wait(); catch (InterruptedException ie) { ie.printstacktrace(); mydish.readytoeat = false; System.out.println(name + " yum"); So? The Child owns the lock on its icecreamdish If the icecreamdish is not ready to eat, the Child releases the lock and waits to be notified when it is full Note the use of a while loop, and not an if statement. It is possible that the Child thread could wake up before it is notified. By using a while loop, the guard will be checked again if such a spurious wake up occurs 14
15 IceCreamMan.serveIceCream private void serveicecream() { // get an ice cream dish IceCreamDish currentdish = dishes.get(0); synchronized (currentdish) { currentdish.readytoeat = true; // notify the dish's owner that the dish is ready currentdish.notify(); // remove the dish from the queue of dishes dishes.remove(currentdish); Note Correct functioning requires both the writer of Child and the writer of IceCreamMan to synchronise on IceCreamDishes. There is nothing here that forces a Child to synchronize. But if she doesn t, then she may get a half-full or even empty IceCreamDish 15
16 notify() vs. notifyall() In the previous examples, we only had one thread waiting for the lock on an object at a time We used notify() to inform the JVM that when lock was available and the waiting thread could resume In general, there could be several threads waiting notifyall() might be more appropriate More in wait() Following a wait(myobject) invocation: The current thread is blocked Unless the current thread has been interrupted, in which case the method exits throwing an InterruptedException. The thread is placed in an internal wait set associated with myobject The lock on myobject is released But all other locks are retained 16
17 notify() Following a myobject.notify() invocation: If one exists, then an arbitrarily chosen thread T is removed from the wait set associated with myobject T must re-obtain the lock on myobject It will be blocked until it does so T will then resume from the point of its wait myobject.notifyall() All threads in the wait set for myobject are removed But they must wait in turn for the synchronization lock on myobject So they will continue one at a time (at least until each respective thread releases the lock) 17
18 NotifyVersusNotifyAll.java We will run the program first using notify() in the main method and then again using notifyall() Usage guidelines Only use notify() if you are sure that the thread that will be notified will be able to use the notification Note that in general you will not know which thread will be notified by the JVM If multiple threads are waiting on one event, but with different conditions to meet, then best to use notifyall() 18
19 Simple example Producer thread synchronized(lock) { value = Math.random(); lock.notifyall(); Consumer Thread 1 synchronized(lock) { While (value < 0.5) { lock.wait(); Consumer Thread 2 synchronized(lock) { While (value >= 0.5) { lock.wait(); 19
Java Threads. Written by John Bell for CS 342, Spring 2018
Java Threads Written by John Bell for CS 342, Spring 2018 Based on chapter 9 of Learning Java, Fourth Edition by Niemeyer and Leuck, and other sources. Processes A process is an instance of a running program.
More informationJava Threads. COMP 585 Noteset #2 1
Java Threads The topic of threads overlaps the boundary between software development and operation systems. Words like process, task, and thread may mean different things depending on the author and the
More informationAnimation Part 2: MoveableShape interface & Multithreading
Animation Part 2: MoveableShape interface & Multithreading MoveableShape Interface In the previous example, an image was drawn, then redrawn in another location Since the actions described above can apply
More informationMultitasking Multitasking allows several activities to occur concurrently on the computer. A distinction is usually made between: Process-based multit
Threads Multitasking Multitasking allows several activities to occur concurrently on the computer. A distinction is usually made between: Process-based multitasking Thread-based multitasking Multitasking
More informationThreads Chate Patanothai
Threads Chate Patanothai Objectives Knowing thread: 3W1H Create separate threads Control the execution of a thread Communicate between threads Protect shared data C. Patanothai Threads 2 What are threads?
More informationNeed for synchronization: If threads comprise parts of our software systems, then they must communicate.
Thread communication and synchronization There are two main aspects to Outline for Lecture 19 multithreaded programming in Java: I. Thread synchronization. thread lifecycle, and thread synchronization.
More informationWhat is a thread anyway?
Concurrency in Java What is a thread anyway? Smallest sequence of instructions that can be managed independently by a scheduler There can be multiple threads within a process Threads can execute concurrently
More informationCOURSE 11 PROGRAMMING III OOP. JAVA LANGUAGE
COURSE 11 PROGRAMMING III OOP. JAVA LANGUAGE PREVIOUS COURSE CONTENT Input/Output Streams Text Files Byte Files RandomAcessFile Exceptions Serialization NIO COURSE CONTENT Threads Threads lifecycle Thread
More information27/04/2012. We re going to build Multithreading Application. Objectives. MultiThreading. Multithreading Applications. What are Threads?
Objectives MultiThreading What are Threads? Interrupting threads Thread properties By Võ Văn Hải Faculty of Information Technologies Summer 2012 Threads priorities Synchronization Callables and Futures
More informationUnit - IV Multi-Threading
Unit - IV Multi-Threading 1 Uni Processing In the early days of computer only one program will occupy the memory. The second program must be in waiting. The second program will be entered whenever first
More informationInfo 408 Distributed Applications Programming Exercise sheet nb. 4
Lebanese University Info 408 Faculty of Science 2017-2018 Section I 1 Custom Connections Info 408 Distributed Applications Programming Exercise sheet nb. 4 When accessing a server represented by an RMI
More informationCSCD 330 Network Programming
CSCD 330 Network Programming Lecture 12 More Client-Server Programming Winter 2019 Reading: References at end of Lecture 1 Introduction So far, Looked at client-server programs with Java Sockets TCP and
More informationCSCD 330 Network Programming
CSCD 330 Network Programming Lecture 12 More Client-Server Programming Winter 2016 Reading: References at end of Lecture 1 Introduction So far, Looked at client-server programs with Java Sockets TCP and
More informationOverview. Processes vs. Threads. Computation Abstractions. CMSC 433, Fall Michael Hicks 1
CMSC 433 Programming Language Technologies and Paradigms Spring 2003 Threads and Synchronization April 1, 2003 Overview What are threads? Thread scheduling, data races, and synchronization Thread mechanisms
More informationCS11 Java. Fall Lecture 7
CS11 Java Fall 2006-2007 Lecture 7 Today s Topics All about Java Threads Some Lab 7 tips Java Threading Recap A program can use multiple threads to do several things at once A thread can have local (non-shared)
More informationCMSC 330: Organization of Programming Languages. Threads Classic Concurrency Problems
: Organization of Programming Languages Threads Classic Concurrency Problems The Dining Philosophers Problem Philosophers either eat or think They must have two forks to eat Can only use forks on either
More informationWeek 7. Concurrent Programming: Thread Synchronization. CS 180 Sunil Prabhakar Department of Computer Science Purdue University
Week 7 Concurrent Programming: Thread Synchronization CS 180 Sunil Prabhakar Department of Computer Science Purdue University Announcements Exam 1 tonight 6:30 pm - 7:30 pm MTHW 210 2 Outcomes Understand
More informationCS180 Review. Recitation Week 15
CS180 Review Recitation Week 15 Announcement Final exam will be held on Thursday(12/17) 8:00~10:00 AM The coverage is comprehensive Project 5 is graded. Check your score in Blackboard. Classes and Methods
More informationCS18000: Programming I
CS18000: Programming I Synchronization 22 February, 2010 Prof. Chris Clifton Concurrency Example: Banking class ATM { public void withdrawcash(acct a) { Scanner sc = new Scanner(System.in); int amount
More information04-Java Multithreading
04-Java Multithreading Join Google+ community http://goo.gl/u7qvs You can ask all your doubts, questions and queries by posting on this G+ community during/after webinar http://openandroidlearning.org
More informationThe Dining Philosophers Problem CMSC 330: Organization of Programming Languages
The Dining Philosophers Problem CMSC 0: Organization of Programming Languages Threads Classic Concurrency Problems Philosophers either eat or think They must have two forks to eat Can only use forks on
More informationCMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Threads Synchronization Refers to mechanisms allowing a programmer to control the execution order of some operations across different threads in a concurrent
More informationCS 159: Parallel Processing
Outline: Concurrency using Java CS 159: Parallel Processing Spring 2007 Processes vs Threads Thread basics Synchronization Locks Examples Avoiding problems Immutable objects Atomic operations High"level
More informationMultithreaded Programming
Multithreaded Programming Multithreaded programming basics Concurrency is the ability to run multiple parts of the program in parallel. In Concurrent programming, there are two units of execution: Processes
More information7. MULTITHREDED PROGRAMMING
7. MULTITHREDED PROGRAMMING What is thread? A thread is a single sequential flow of control within a program. Thread is a path of the execution in a program. Muti-Threading: Executing more than one thread
More informationCMSC 330: Organization of Programming Languages. The Dining Philosophers Problem
CMSC 330: Organization of Programming Languages Threads Classic Concurrency Problems The Dining Philosophers Problem Philosophers either eat or think They must have two forks to eat Can only use forks
More informationSynchronization synchronization.
Unit 4 Synchronization of threads using Synchronized keyword and lock method- Thread pool and Executors framework, Futures and callable, Fork-Join in Java. Deadlock conditions 1 Synchronization When two
More informationMulti-threaded programming in Java
Multi-threaded programming in Java Java allows program to specify multiple threads of execution Provides instructions to ensure mutual exclusion, and selective blocking/unblocking of threads What is a
More informationCMSC 433 Programming Language Technologies and Paradigms. Spring 2013
1 CMSC 433 Programming Language Technologies and Paradigms Spring 2013 Wait / Notify / NotifyAll Optimistic Retries Composition Follow-up (the risk I mentioned) ReentrantLock, Wait, Notify, NotifyAll Some
More informationCOMP31212: Concurrency A Review of Java Concurrency. Giles Reger
COMP31212: Concurrency A Review of Java Concurrency Giles Reger Outline What are Java Threads? In Java, concurrency is achieved by Threads A Java Thread object is just an object on the heap, like any other
More informationCS360 Lecture 12 Multithreading
CS360 Lecture 12 Multithreading Thursday, March 11, 2004 Reading Multithreading: Chapter 16 Thread States At any time, a thread can be in one of several thread states: - Born: this is the time when the
More informationLecture 8: September 30
CMPSCI 377 Operating Systems Fall 2013 Lecture 8: September 30 Lecturer: Prashant Shenoy Scribe: Armand Halbert 8.1 Semaphores A semaphore is a more generalized form of a lock that can be used to regulate
More informationJava Threads. Introduction to Java Threads
Java Threads Resources Java Threads by Scott Oaks & Henry Wong (O Reilly) API docs http://download.oracle.com/javase/6/docs/api/ java.lang.thread, java.lang.runnable java.lang.object, java.util.concurrent
More informationLecture 9: Introduction to Monitors
COMP 150-CCP Concurrent Programming Lecture 9: Introduction to Monitors Dr. Richard S. Hall rickhall@cs.tufts.edu Concurrent programming February 14, 2008 Abstracting Locking Details Recall our discussion
More informationContents. 6-1 Copyright (c) N. Afshartous
Contents 1. Classes and Objects 2. Inheritance 3. Interfaces 4. Exceptions and Error Handling 5. Intro to Concurrency 6. Concurrency in Java 7. Graphics and Animation 8. Applets 6-1 Copyright (c) 1999-2004
More informationpublic class Shared0 { private static int x = 0, y = 0;
A race condition occurs anytime that the execution of one thread interferes with the desired behavior of another thread. What is the expected postcondition for the following bump() method? What should
More informationProgramming Language Concepts: Lecture 11
Programming Language Concepts: Lecture 11 Madhavan Mukund Chennai Mathematical Institute madhavan@cmi.ac.in PLC 2011, Lecture 11, 01 March 2011 Concurrent Programming Monitors [Per Brinch Hansen, CAR Hoare]
More informationTwo Types of Semaphores
Two Types of Semaphores Counting semaphore integer value can range over an unrestricted domain. Binary semaphore integer value can range only between 0 and 1; can be simpler to implement. Can implement
More informationModule - 4 Multi-Threaded Programming
Terminologies Module - 4 Multi-Threaded Programming Process: A program under execution is called as process. Thread: A smallest component of a process that can be executed independently. OR A thread is
More informationProgramming in Parallel COMP755
Programming in Parallel COMP755 All games have morals; and the game of Snakes and Ladders captures, as no other activity can hope to do, the eternal truth that for every ladder you hope to climb, a snake
More informationMonitors & Condition Synchronization
Feb. 15, 2012 Monitors & condition Synchronization Concepts: monitors: encapsulated data + access procedures mutual exclusion + condition synchronization single access procedure active in the monitor Models:
More informationCS 556 Distributed Systems
CS 556 Distributed Systems Tutorial on 4 Oct 2002 Threads A thread is a lightweight process a single sequential flow of execution within a program Threads make possible the implementation of programs that
More informationCS 351 Design of Large Programs Threads and Concurrency
CS 351 Design of Large Programs Threads and Concurrency Brooke Chenoweth University of New Mexico Spring 2018 Concurrency in Java Java has basic concurrency support built into the language. Also has high-level
More informationSynchronization in Java
Synchronization in Java Nelson Padua-Perez Bill Pugh Department of Computer Science University of Maryland, College Park Synchronization Overview Unsufficient atomicity Data races Locks Deadlock Wait /
More informationSummary Semaphores. Passing the Baton any await statement. Synchronisation code not linked to the data
Lecture 4 Monitors Summary Semaphores Good news Simple, efficient, expressive Passing the Baton any await statement Bad news Low level, unstructured omit a V: deadlock omit a P: failure of mutex Synchronisation
More informationChair of Software Engineering. Java and C# in depth. Carlo A. Furia, Marco Piccioni, Bertrand Meyer. Java: concurrency
Chair of Software Engineering Carlo A. Furia, Marco Piccioni, Bertrand Meyer Java: concurrency Outline Java threads thread implementation sleep, interrupt, and join threads that return values Thread synchronization
More informationWhat's wrong with Semaphores?
Next: Monitors and Condition Variables What is wrong with semaphores? Monitors What are they? How do we implement monitors? Two types of monitors: Mesa and Hoare Compare semaphore and monitors Lecture
More informationJAVA and J2EE UNIT - 4 Multithreaded Programming And Event Handling
JAVA and J2EE UNIT - 4 Multithreaded Programming And Event Handling Multithreaded Programming Topics Multi Threaded Programming What are threads? How to make the classes threadable; Extending threads;
More informationJava Monitors. Parallel and Distributed Computing. Department of Computer Science and Engineering (DEI) Instituto Superior Técnico.
Java Monitors Parallel and Distributed Computing Department of Computer Science and Engineering (DEI) Instituto Superior Técnico October 19, 2010 Monteiro, Costa (DEI / IST) Parallel and Distributed Computing
More informationUnit 4. Thread class & Runnable Interface. Inter Thread Communication
Unit 4 Thread class & Runnable Interface. Inter Thread Communication 1 Multithreaded Programming Java provides built-in support for multithreaded programming. A multithreaded program contains two or more
More informationTechniques of Java Programming: Concurrent Programming in Java
Techniques of Java Programming: Concurrent Programming in Java Manuel Oriol May 11, 2006 1 Introduction Threads are one of the fundamental structures in Java. They are used in a lot of applications as
More informationSynchronization. CS 475, Spring 2018 Concurrent & Distributed Systems
Synchronization CS 475, Spring 2018 Concurrent & Distributed Systems Review: Threads: Memory View code heap data files code heap data files stack stack stack stack m1 m1 a1 b1 m2 m2 a2 b2 m3 m3 a3 m4 m4
More informationOnly one thread can own a specific monitor
Java 5 Notes Threads inherit their priority and daemon properties from their creating threads The method thread.join() blocks and waits until the thread completes running A thread can have a name for identification
More informationMultithreading using Java. Dr. Ferdin Joe John Joseph
Multithreading using Java Dr. Ferdin Joe John Joseph 1 Agenda Introduction Thread Applications Defining Threads Java Threads and States Priorities Accessing Shared Resources Synchronisation Assignment
More informationAdvanced Concepts of Programming
Berne University of Applied Sciences E. Benoist / E. Dubuis January 2005 1 Multithreading in Java Java provides the programmer with built-in threading capabilities The programmer can create and manipulate
More informationChapter 32 Multithreading and Parallel Programming
Chapter 32 Multithreading and Parallel Programming 1 Objectives To get an overview of multithreading ( 32.2). To develop task classes by implementing the Runnable interface ( 32.3). To create threads to
More informationCOMPSCI 230 Threading Week8. Figure 1 Thread status diagram [http://www.programcreek.com/2009/03/thread-status/]
COMPSCI 230 Threading Week8 Figure 1 Thread status diagram [http://www.programcreek.com/2009/03/thread-status/] Synchronization Lock DeadLock Why do we need Synchronization in Java? If your code is executing
More informationThreads Questions Important Questions
Threads Questions Important Questions https://dzone.com/articles/threads-top-80-interview https://www.journaldev.com/1162/java-multithreading-concurrency-interviewquestions-answers https://www.javatpoint.com/java-multithreading-interview-questions
More informationPerformance Throughput Utilization of system resources
Concurrency 1. Why concurrent programming?... 2 2. Evolution... 2 3. Definitions... 3 4. Concurrent languages... 5 5. Problems with concurrency... 6 6. Process Interactions... 7 7. Low-level Concurrency
More informationMonitors; Software Transactional Memory
Monitors; Software Transactional Memory Parallel and Distributed Computing Department of Computer Science and Engineering (DEI) Instituto Superior Técnico March 17, 2016 CPD (DEI / IST) Parallel and Distributed
More informationSynchronization in Concurrent Programming. Amit Gupta
Synchronization in Concurrent Programming Amit Gupta Announcements Project 1 grades are out on blackboard. Detailed Grade sheets to be distributed after class. Project 2 grades should be out by next Thursday.
More informationIntroduction to Java Threads
Object-Oriented Programming Introduction to Java Threads RIT CS 1 "Concurrent" Execution Here s what could happen when you run this Java program and launch 3 instances on a single CPU architecture. The
More informationRecap. Contents. Reenterancy of synchronized. Explicit Locks: ReentrantLock. Reenterancy of synchronise (ctd) Advanced Thread programming.
Lecture 07: Advanced Thread programming Software System Components 2 Behzad Bordbar School of Computer Science, University of Birmingham, UK Recap How to deal with race condition in Java Using synchronised
More informationThreads and Parallelism in Java
Threads and Parallelism in Java Java is one of the few main stream programming languages to explicitly provide for user-programmed parallelism in the form of threads. A Java programmer may organize a program
More informationMultithread Computing
Multithread Computing About This Lecture Purpose To learn multithread programming in Java What You Will Learn ¾ Benefits of multithreading ¾ Class Thread and interface Runnable ¾ Thread methods and thread
More informationLecture 29: Java s synchronized statement
COMP 322: Fundamentals of Parallel Programming Lecture 29: Java s synchronized statement Vivek Sarkar Department of Computer Science, Rice University vsarkar@rice.edu https://wiki.rice.edu/confluence/display/parprog/comp322
More informationUnit III Rupali Sherekar 2017
Unit III Exceptions An exception is an abnormal condition that arises in a code sequence at run time. In other words, an exception is a run-time error. In computer languages that do not support exception
More informationCS61B, Spring 2003 Discussion #17 Amir Kamil UC Berkeley 5/12/03
CS61B, Spring 2003 Discussion #17 Amir Kamil UC Berkeley 5/12/03 Topics: Threading, Synchronization 1 Threading Suppose we want to create an automated program that hacks into a server. Many encryption
More informationSynchronized Methods of Old Versions of Java
Administrivia Assignment #4 is out Due Thursday April 8, 10:00pm no late assignments will be accepted Sign up in labs next week for a demo time In case you hadn t noticed Classes end Thursday April 15
More informationwait with priority An enhanced version of the wait operation accepts an optional priority argument:
wait with priority An enhanced version of the wait operation accepts an optional priority argument: syntax: .wait the smaller the value of the parameter, the highest the priority
More informationG52CON: Concepts of Concurrency
G52CON: Concepts of Concurrency Lecture 11: Semaphores I" Brian Logan School of Computer Science bsl@cs.nott.ac.uk Outline of this lecture" problems with Peterson s algorithm semaphores implementing semaphores
More informationPrinciples of Software Construction: Concurrency, Part 2
Principles of Software Construction: Concurrency, Part 2 Josh Bloch Charlie Garrod School of Computer Science 1 Administrivia Homework 5a due now Homework 5 framework goals: Functionally correct Well documented
More informationComputation Abstractions. Processes vs. Threads. So, What Is a Thread? CMSC 433 Programming Language Technologies and Paradigms Spring 2007
CMSC 433 Programming Language Technologies and Paradigms Spring 2007 Threads and Synchronization May 8, 2007 Computation Abstractions t1 t1 t4 t2 t1 t2 t5 t3 p1 p2 p3 p4 CPU 1 CPU 2 A computer Processes
More informationMultiThreading 07/01/2013. Session objectives. Introduction. Introduction. Advanced Java Programming Course
Advanced Java Programming Course MultiThreading By Võ Văn Hải Faculty of Information Technologies Industrial University of Ho Chi Minh City Session objectives Introduction Creating thread Thread class
More informationAdvanced Java Programming Course. MultiThreading. By Võ Văn Hải Faculty of Information Technologies Industrial University of Ho Chi Minh City
Advanced Java Programming Course MultiThreading By Võ Văn Hải Faculty of Information Technologies Industrial University of Ho Chi Minh City Session objectives Introduction Creating thread Thread class
More informationModels of concurrency & synchronization algorithms
Models of concurrency & synchronization algorithms Lecture 3 of TDA383/DIT390 (Concurrent Programming) Carlo A. Furia Chalmers University of Technology University of Gothenburg SP3 2016/2017 Today s menu
More informationNote: Each loop has 5 iterations in the ThreeLoopTest program.
Lecture 23 Multithreading Introduction Multithreading is the ability to do multiple things at once with in the same application. It provides finer granularity of concurrency. A thread sometimes called
More informationMultitasking. Multitasking allows several activities to occur concurrently on the computer Levels of multitasking: Process based multitasking
Java Thread Multitasking Multitasking allows several activities to occur concurrently on the computer Levels of multitasking: Process based multitasking Allows programs (processes) to run concurrently
More informationJava Threads. What Are Threads? General-purpose solution for managing concurrency. Multiple independent execution streams. Shared state.
Java Threads What Are Threads? Shared state (variables, files) Threads General-purpose solution for managing concurrency. Multiple independent execution streams Shared state SoftEng Group 1 What Are Threads
More informationJava Programming Lecture 23
Java Programming Lecture 23 Alice E. Fischer April 19, 2012 Alice E. Fischer () Java Programming - L23... 1/20 April 19, 2012 1 / 20 Outline 1 Thread Concepts Definition and Purpose 2 Java Threads Creation
More informationJAVA. Lab 12 & 13: Multithreading
JAVA Prof. Navrati Saxena TA: Rochak Sachan Lab 12 & 13: Multithreading Outline: 2 What is multithreaded programming? Thread model Synchronization Thread Class and Runnable Interface The Main Thread Creating
More informationBasics of. Multithreading in Java
Basics of programming 3 Multithreading in Java Thread basics Motivation in most cases sequential (single threaded) applications are not adequate it s easier to decompose tasks into separate instruction
More informationThreads. Definitions. Process Creation. Process. Thread Example. Thread. From Volume II
Definitions A glossary Threads From Volume II Copyright 1998-2002 Delroy A. Brinkerhoff. All Rights Reserved. Threads Slide 1 of 30 PMultitasking: (concurrent ramming, multiramming) the illusion of running
More informationCS 455: INTRODUCTION TO DISTRIBUTED SYSTEMS [THREADS] Frequently asked questions from the previous class survey
CS 455: INTRODUCTION TO DISTRIBUTED SYSTEMS [THREADS] Threads block when they can t get that lock Wanna have your threads stall? Go ahead, synchronize it all The antidote to this liveness pitfall? Keeping
More informationPre- and post- CS protocols. CS 361 Concurrent programming Drexel University Fall 2004 Lecture 7. Other requirements for a mutual exclusion algorithm
CS 361 Concurrent programming Drexel University Fall 2004 Lecture 7 Bruce Char and Vera Zaychik. All rights reserved by the author. Permission is given to students enrolled in CS361 Fall 2004 to reproduce
More informationProgramming Java. Multithreaded Programming
Programming Multithreaded Programming Incheon Paik 1 Contents An Overview of Threads Creating Threads Synchronization Deadlock Thread Communication 2 An Overview of Threads What is a Thread? A sequence
More informationParallel Programming Languages COMP360
Parallel Programming Languages COMP360 The way the processor industry is going, is to add more and more cores, but nobody knows how to program those things. I mean, two, yeah; four, not really; eight,
More informationUNIT IV MULTITHREADING AND GENERIC PROGRAMMING
UNIT IV MULTITHREADING AND GENERIC PROGRAMMING Differences between multithreading and multitasking, thread life cycle, creating threads, creating threads, synchronizing threads, Inter-thread communication,
More informationG51PGP Programming Paradigms. Lecture 009 Concurrency, exceptions
G51PGP Programming Paradigms Lecture 009 Concurrency, exceptions 1 Reminder subtype polymorphism public class TestAnimals public static void main(string[] args) Animal[] animals = new Animal[6]; animals[0]
More informationMonitors; Software Transactional Memory
Monitors; Software Transactional Memory Parallel and Distributed Computing Department of Computer Science and Engineering (DEI) Instituto Superior Técnico October 18, 2012 CPD (DEI / IST) Parallel and
More informationConcurrent Programming using Threads
Concurrent Programming using Threads Threads are a control mechanism that enable you to write concurrent programs. You can think of a thread in an object-oriented language as a special kind of system object
More informationOverview. CMSC 330: Organization of Programming Languages. Concurrency. Multiprocessors. Processes vs. Threads. Computation Abstractions
CMSC 330: Organization of Programming Languages Multithreaded Programming Patterns in Java CMSC 330 2 Multiprocessors Description Multiple processing units (multiprocessor) From single microprocessor to
More informationConcurrency in Java Prof. Stephen A. Edwards
Concurrency in Java Prof. Stephen A. Edwards The Java Language Developed by James Gosling et al. at Sun Microsystems in the early 1990s Originally called Oak, first intended application was as an OS for
More informationCmpSci 187: Programming with Data Structures Spring 2015
CmpSci 187: Programming with Data Structures Spring 2015 Lecture #13, Concurrency, Interference, and Synchronization John Ridgway March 12, 2015 Concurrency and Threads Computers are capable of doing more
More informationExercises and Labs. Part I. Exercises
Exercises and Labs Part I Exercises 7 Exercises and Labs Exercise 1 Semaphores Answer the questions below: 1. Sometimes, multiple threads in a program write to the same file concurrently. One example
More informationHandouts. 1 Handout for today! Recap. Homework #2 feedback. Last Time. What did you think? HW3a: ThreadBank. Today. Small assignment.
Handouts CS193J: Programming in Java Summer Quarter 2003 Lecture 10 Thread Interruption, Cooperation (wait/notify), Swing Thread, Threading conclusions 1 Handout for today! #21: Threading 3 #22: HW3a:
More informationProblems with Concurrency. February 19, 2014
with Concurrency February 19, 2014 s with concurrency interleavings race conditions dead GUI source of s non-determinism deterministic execution model 2 / 30 General ideas Shared variable Access interleavings
More informationMonitors & Condition Synchronisation
Chapter 5 Monitors & Condition Synchronisation controller 1 Monitors & Condition Synchronisation Concepts: monitors (and controllers): encapsulated data + access procedures + mutual exclusion + condition
More informationRobotics and Autonomous Systems
1 / 38 Robotics and Autonomous Systems Lecture 10: Threads and Multitasking Robots Simon Parsons Department of Computer Science University of Liverpool 2 / 38 Today Some more programming techniques that
More informationThreads and Java Memory Model
Threads and Java Memory Model Oleg Šelajev @shelajev oleg@zeroturnaround.com October 6, 2014 Agenda Threads Basic synchronization Java Memory Model Concurrency Concurrency - several computations are executing
More information