Programação Concorrente/Paralela em Java

Transcrição

1 em Java Resolução do Exercício 1 public class Cont extends Thread { protected int ct; public Cont() { ct=0; public synchronized void inc() { ct++; public void run() { for (int i=0; i<100; i++) { inc(); System.out.print(" i= " + ct); public static void main(string[] arg) { System.out.print("\nSequencial"); new Cont().run(); new Cont().run(); System.out.print("\nParalelo"); new Cont().start(); new Cont().run(); Resolução do Exercício 2 public class MyClock extends Thread { public MyClock() { start(); public void run() { for(int i=0; i<10; i++) { sleep(1000); catch (InterruptedException e) { System.out.println(i + " segundos"); System.out.println("terminou"); public static void main(string[] arg) { new MyClock(); // durante 10 segundos Arquitecturas Paralelas I 13 João Luís Sobral 2002

2 Resolução do Exercício 3 // Versão do contador com indicação de falha public class CannotIncException extends Exception { public class CannotDecException extends Exception { public class Cont1 { private int ct; public void Cont1() { ct=0; public void inc() throws CannotIncException { if (ct==100) throw new CannotIncException(); else ct++; public void dec() throws CannotDecException { if (ct==0) throw new CannotDecException(); else ct--; // Versão com métodos guardados com base no estado físico public class Cont2 { private int ct; public void Cont2() { ct=0; public synchronized void inc() { while (ct>=100) { wait(); // suspende até ser acordado por um dec catch(interruptedexception e) { ct++; if (ct==1) notifyall(); // para acordar os que suspenderam em dec public synchronized void dec() { while (ct<=0) { wait(); catch(interruptedexception e) { ct--; if (ct==99) notifyall(); Arquitecturas Paralelas I 14 João Luís Sobral 2002

3 Resolução do Exercício 3 (continuação) // Versão com métodos guardados com base no estado lógico public class Cont3 { private int ct; private String estado; public void Cont3() { ct=0; estado = "min"; public synchronized void inc() { while (estado=="max") { wait(); // suspende até ser acordado por um dec catch(interruptedexception e) { if (estado=="min") { notifyall(); estado="med"; ct++; if (ct==100) estado="max"; public synchronized void dec() { while (estado=="min") { wait(); catch(interruptedexception e) { if (estado=="max") { notifyall(); estado="med"; ct--; if (ct==0) estado="min"; Arquitecturas Paralelas I 15 João Luís Sobral 2002

4 Resolução do Exercício 4 // Counter.java public interface Counter extends Remote { void count() throws RemoteException; // CounterServer.java import java.rmi.*; import java.rmi.server.*; public class CounterServer extends RemoteObject implements Counter { public void count() throws RemoteException { for(int i=0; i<100; i++) System.out.print(i + " "); // CounterServerApp.java import javax.naming.*; import javax.rmi.portableremoteobject; public class CounterServerApp { public static void main(string args[]) { CounterServer cs1 = new CounterServer(); PortableRemoteObject.exportObject(cs1); CounterServer cs2 = new CounterServer(); PortableRemoteObject.exportObject(cs2); Context ctx = new InitialContext(); ctx.rebind("counterserver1",cs1); ctx.rebind("counterserver2",cs2); BufferedReader rdr = new BufferedReader(new InputStreamReader(System.in)); while (true) { System.out.println("Type EXIT to shutdown the server"); if ("EXIT".equals(rdr.readLine())) { break; ctx.unbind("counterserver1"); ctx.unbind("counterserver2"); PortableRemoteObject.unexportObject(cs1); PortableRemoteObject.unexportObject(cs2); catch(exception e) { e.printstacktrace(); Arquitecturas Paralelas I 16 João Luís Sobral 2002

5 Resolução do Exercício 4 (continuação) // AssCounter.java public class AssCounter extends Thread { Counter mycount; public AssCounter(Counter c) { mycount =c; public void run() { mycount.count(); catch(exception ex) { ex.printstacktrace(); // CounterClient.java import javax.naming.*; import java.util.*; public class CounterClient { public static Counter findcounter(string cnt, Context ctx) { Counter cs=null; cs = (Counter) PortableRemoteObject.narrow( ctx.lookup(cnt), Counter.class); catch(exception ex) { ex.printstacktrace(); return(cs); public static void main(string args[]) { Context ctx = new InitialContext(); Counter cs1 = findcounter("counterserver1",ctx); Counter cs2 = findcounter("counterserver2",ctx); // Execução sequencial cs1.count(); cs2.count(); // Execução em paralelo (new AssCounter(cs1)).start(); cs2.count(); catch(exception ex) { ex.printstacktrace(); Arquitecturas Paralelas I 17 João Luís Sobral 2002

6 Resolução do Exercício 5. São alteradas as classes AssCounter e CounterClient e é adicionado a interface Callback: // Callback.java public interface Callback { void callop(); // AssCounter.java public class AssCounter extends Thread { Counter mycount; Callback myclient; public AssCounter(Counter c, Callback cl) { mycount =c; myclient = cl; public void run() { mycount.count(); catch(exception ex) { ex.printstacktrace(); myclient.callop(); // CounterClient.java public class CounterClient implements Callback { public void execute() { Context ctx = new InitialContext(); Counter cs1 = findcounter("counterserver1",ctx); Counter cs2 = findcounter("counterserver2",ctx); // Execução em paralelo new AssCounter(cs1,this).start(); new AssCounter(cs2,this).start(); catch(exception ex) { ex.printstacktrace(); public void callop() { System.out.println("Done"); public static void main(string args[]) { new CounterClient().execute(); Arquitecturas Paralelas I 18 João Luís Sobral 2002

7 Resolução do Exercício 6 // Counter.cs using System; using System.Runtime.Remoting.Messaging; public abstract class Counter: MarshalByRefObject { public abstract void count(); // CounterServer.cs using System; using System.Runtime.Remoting; using System.Runtime.Remoting.Channels.Http; using System.Runtime.Remoting.Channels; using System.Runtime.Remoting.Messaging; using System.Threading; class CounterServer : Counter { public override void count() { for(int i=0; i<100; i++) { Console.Write(i + " "); Thread.Sleep(50); Console.WriteLine(); class ServerStartup { static void Main(string[] args) { Console.WriteLine ("ServerStartup.Main(): Server started"); HttpChannel chnl = new HttpChannel(1234); ChannelServices.RegisterChannel(chnl); RemotingConfiguration.RegisterWellKnownServiceType( typeof(counterserver), "CounterServer.soap", WellKnownObjectMode.Singleton); // the server will keep running until keypress. Console.ReadLine(); Arquitecturas Paralelas I 19 João Luís Sobral 2002

8 Resolução do Exercício 6 (continuação) // CounterClient.cs using System; using System.Runtime.Remoting; using System.Runtime.Remoting.Channels.Http; using System.Runtime.Remoting.Channels.Tcp; using System.Runtime.Remoting.Channels; using System.Runtime.Remoting.Proxies; class CounterClient { delegate void CounterDelegate(); static void Main(string[] args) { HttpChannel channel = new HttpChannel(); ChannelServices.RegisterChannel(channel); Counter obj = (Counter) Activator.GetObject( typeof(counter), " Console.WriteLine("Client.Main(): Reference to rem.obj. acquired"); // execução sequencial obj.count(); obj.count(); // execução em paralelo CounterDelegate cdel1 = new CounterDelegate(obj.count); IAsyncResult svasy1 = cdel1.begininvoke(null,null); Console.WriteLine("Client.Main(): Invocation1 done"); CounterDelegate cdel2 = new CounterDelegate(obj.count); IAsyncResult svasy2 = cdel2.begininvoke(null,null); Console.WriteLine("Client.Main(): Invocation2 done"); cdel1.endinvoke(svasy1); Console.WriteLine("EndInvoke1 returned successfully "); catch (Exception e) { Console.WriteLine("EXCEPTION during EndInvoke1"); cdel2.endinvoke(svasy2); Console.WriteLine("EndInvoke2 returned successfully"); catch (Exception e) { Console.WriteLine("EXCEPTION during EndInvoke2"); // wait for keypress Console.ReadLine(); Arquitecturas Paralelas I 20 João Luís Sobral 2002