From b63be079f7aa961b40364ad3dda71cbd43f34bd0 Mon Sep 17 00:00:00 2001 From: tomcat8 Date: Thu, 7 Nov 2019 18:15:00 +0000 Subject: [PATCH] Initialised task --- LICENSE | 202 ++++++++++++++++++ NOTICE | 5 + .../cam/jsh77/fjava/tick3/BankSimulator.java | 101 +++++++++ .../cam/jsh77/fjava/tick3/MessageQueue.java | 27 +++ .../jsh77/fjava/tick3/ProducerConsumer.java | 54 +++++ .../ac/cam/jsh77/fjava/tick3/QueueTest.java | 118 ++++++++++ .../jsh77/fjava/tick3/UnsafeMessageQueue.java | 53 +++++ 7 files changed, 560 insertions(+) create mode 100644 LICENSE create mode 100644 NOTICE create mode 100644 src/uk/ac/cam/jsh77/fjava/tick3/BankSimulator.java create mode 100644 src/uk/ac/cam/jsh77/fjava/tick3/MessageQueue.java create mode 100644 src/uk/ac/cam/jsh77/fjava/tick3/ProducerConsumer.java create mode 100644 src/uk/ac/cam/jsh77/fjava/tick3/QueueTest.java create mode 100644 src/uk/ac/cam/jsh77/fjava/tick3/UnsafeMessageQueue.java diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..7a4a3ea --- /dev/null +++ b/LICENSE @@ -0,0 +1,202 @@ + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright [yyyy] [name of copyright owner] + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. \ No newline at end of file diff --git a/NOTICE b/NOTICE new file mode 100644 index 0000000..40302c2 --- /dev/null +++ b/NOTICE @@ -0,0 +1,5 @@ +Further Java Ticklet 3 +Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + +This software comprises a programming exercise provided by the Department of Computer Science and Technology. +Ownership rests jointly with the original exercise authors and the person who undertook the exercise. \ No newline at end of file diff --git a/src/uk/ac/cam/jsh77/fjava/tick3/BankSimulator.java b/src/uk/ac/cam/jsh77/fjava/tick3/BankSimulator.java new file mode 100644 index 0000000..837cb82 --- /dev/null +++ b/src/uk/ac/cam/jsh77/fjava/tick3/BankSimulator.java @@ -0,0 +1,101 @@ +/* + * Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package uk.ac.cam.jsh77.fjava.tick3; + +import java.util.Arrays; +import java.util.Random; + +public class BankSimulator { + + private class BankAccount { + + private int balance; + private int acc; + + BankAccount(int accountNumber, int deposit) { + balance = deposit; + acc = accountNumber; + } + + public int getAccountNumber() { + return acc; + } + + public void transferTo(BankAccount b, int amount) { + balance -= amount; + b.balance += amount; + } + } + + private static Random r = new Random(); + + private class RoboTeller extends Thread { + public void run() { + // Robots work from 9am until 5pm; one customer per second + for (int i = 9 * 60 * 60; i < 17 * 60 * 60; i++) { + int a = r.nextInt(account.length); + int b = r.nextInt(account.length); + account[a].transferTo(account[b], r.nextInt(100)); + } + } + } + + private int capital; + private BankAccount[] account; + private RoboTeller[] teller; + + public BankSimulator(int capital, int accounts, int tellers) { + this.capital = capital; + this.account = new BankAccount[accounts]; + this.teller = new RoboTeller[tellers]; + for (int i = 0; i < account.length; i++) { + account[i] = new BankAccount(i, capital / account.length); + } + } + + public int getCapital() { + return capital; + } + + public void runDay() { + for (int i = 0; i < teller.length; i++) { + teller[i] = new RoboTeller(); + } + + for (int i = 0; i < teller.length; i++) { + teller[i].start(); + } + + int done = 0; + while (done < teller.length) { + try { + teller[done].join(); + done++; + } catch (InterruptedException e) { + // IGNORED exception + } + } + + capital = Arrays.stream(account).mapToInt(a -> a.balance).sum(); + } + + public static void main(String[] args) { + BankSimulator javaBank = new BankSimulator(10000, 10, 100); + javaBank.runDay(); + System.out.printf("Capital at close: %d pounds%n", javaBank.getCapital()); + } +} diff --git a/src/uk/ac/cam/jsh77/fjava/tick3/MessageQueue.java b/src/uk/ac/cam/jsh77/fjava/tick3/MessageQueue.java new file mode 100644 index 0000000..0b0168e --- /dev/null +++ b/src/uk/ac/cam/jsh77/fjava/tick3/MessageQueue.java @@ -0,0 +1,27 @@ +/* + * Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package uk.ac.cam.jsh77.fjava.tick3; + +// A FIFO queue of items of type T +public interface MessageQueue { + + // place msg on back of queue + public abstract void put(T msg); + + // block until queue length > 0; return head of queue + public abstract T take(); +} diff --git a/src/uk/ac/cam/jsh77/fjava/tick3/ProducerConsumer.java b/src/uk/ac/cam/jsh77/fjava/tick3/ProducerConsumer.java new file mode 100644 index 0000000..6e59d4b --- /dev/null +++ b/src/uk/ac/cam/jsh77/fjava/tick3/ProducerConsumer.java @@ -0,0 +1,54 @@ +/* + * Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package uk.ac.cam.jsh77.fjava.tick3; + +class ProducerConsumer { + private MessageQueue m = new UnsafeMessageQueue(); + + private class Producer implements Runnable { + char[] cl = "Department of Computer Science and Technology".toCharArray(); + + public void run() { + for (char c : cl) { + m.put(c); + try { + Thread.sleep(500); + } catch (InterruptedException e) { + e.printStackTrace(); + } + } + } + } + + private class Consumer implements Runnable { + public void run() { + while (true) { + System.out.print(m.take()); + System.out.flush(); + } + } + } + + void execute() { + new Thread(new Producer()).start(); + new Thread(new Consumer()).start(); + } + + public static void main(String[] args) { + new ProducerConsumer().execute(); + } +} diff --git a/src/uk/ac/cam/jsh77/fjava/tick3/QueueTest.java b/src/uk/ac/cam/jsh77/fjava/tick3/QueueTest.java new file mode 100644 index 0000000..c1ce6e6 --- /dev/null +++ b/src/uk/ac/cam/jsh77/fjava/tick3/QueueTest.java @@ -0,0 +1,118 @@ +/* + * Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package uk.ac.cam.jsh77.fjava.tick3; + +public class QueueTest { + + private class Producer extends Thread { + private int sent = 0; + + public void run() { + for (int i = 0; i < 50000; ++i) { + q.put("" + i); + sent++; + } + } + + public int numberProduced() { + return sent; + } + } + + private class Consumer extends Thread { + private int recv = 0; + + public void run() { + while (!q.take().equals("EOF")) { + recv++; + } + q.put("EOF"); + } + + public int numberConsumed() { + return recv; + } + } + + private MessageQueue q; + private Consumer[] consumers; + private Producer[] producers; + + QueueTest(MessageQueue q, int c, int p) { + this.q = q; + consumers = new Consumer[c]; + for (int i = 0; i < c; ++i) { + consumers[i] = new Consumer(); + } + producers = new Producer[p]; + for (int i = 0; i < p; ++i) { + producers[i] = new Producer(); + } + } + + public void run() { + + for (Consumer c : consumers) { + c.start(); + } + + for (Producer p : producers) { + p.start(); + } + + for (Producer p : producers) { + try { + p.join(); + } catch (InterruptedException e) { + // IGNORE exception + } + } + q.put("EOF"); + // terminate join at 10 secs since EOF marker may get lost + for (Consumer c : consumers) { + try { + c.join(10000); + } catch (InterruptedException e) { + // IGNORE exception + } + } + + int recv = 0; + for (Consumer consumer : consumers) { + recv += consumer.numberConsumed(); + } + int sent = 0; + for (Producer p : producers) { + sent += p.numberProduced(); + } + System.out.println(recv + " / " + sent); + } + + public static void main(String[] args) { + System.out.println("** UNSAFE ** "); + new QueueTest(new UnsafeMessageQueue(), 1, 1).run(); + new QueueTest(new UnsafeMessageQueue(), 3, 1).run(); + new QueueTest(new UnsafeMessageQueue(), 1, 3).run(); + new QueueTest(new UnsafeMessageQueue(), 3, 3).run(); + + // System.out.println("** SAFE ** "); + // new QueueTest(new SafeMessageQueue(), 1, 1).run(); + // new QueueTest(new SafeMessageQueue(), 3, 1).run(); + // new QueueTest(new SafeMessageQueue(), 1, 3).run(); + // new QueueTest(new SafeMessageQueue(), 3, 3).run(); + } +} diff --git a/src/uk/ac/cam/jsh77/fjava/tick3/UnsafeMessageQueue.java b/src/uk/ac/cam/jsh77/fjava/tick3/UnsafeMessageQueue.java new file mode 100644 index 0000000..ad1abc4 --- /dev/null +++ b/src/uk/ac/cam/jsh77/fjava/tick3/UnsafeMessageQueue.java @@ -0,0 +1,53 @@ +/* + * Copyright 2019 Andrew Rice , Alastair Beresford , J.S. Hillion + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package uk.ac.cam.jsh77.fjava.tick3; + +public class UnsafeMessageQueue implements MessageQueue { + private static class Link { + L val; + Link next; + + Link(L val) { + this.val = val; + this.next = null; + } + } + + private Link first = null; + private Link last = null; + + public void put(T val) { + // TODO: given a new "val", create a new Link + // element to contain it and update "first" and + // "last" as appropriate + } + + public T take() { + while (first == null) { // use a loop to block thread until data is available + try { + Thread.sleep(100); + } catch (InterruptedException ie) { + // Ignored exception + // TODO: what causes this exception to be thrown? and what should + // you do with it ideally? + } + } + // TODO: retrieve "val" from "first", update "first" to refer + // to next element in list (if any). Return "val" + return null; + } +}