Introduction
写一个管理进程的library，这门课其实考察的不是代码，而是熟悉整个软件开发流程。
Objectives
The main objectives of this assignment are:
- to practise software project management (Agile);
- to gain experience in using version control systems (git);
- to gain experience in reading code documentation;
- to gain experience in writing code documentation;
- to gain experience in designing unit and integration tests.
Note This assignment specification aims to provide as complete a description of this assessment task as possible. However, as with any specification, there will always be things we should have said that we have left out and areas in which we could have done a better job of explanation. As a result, you are strongly encouraged to ask any questions of clarification you might have, either by raising them during a lecture or by posting them on the iLearn discussion forum devoted to this assignment.
The Specification
You have to develop a small library, in Java. The library should provide an interface to interact with other programs, typically shell scripts, not necessarily written in Java. More precisely, the objective is to be able to programmatically interact with a program that can read its input from the standard input and produce its results, as a string, on the standard output.
For this assignment, you may have to look up and learn by yourself, some concepts (e.g. standard input, output). The code to be written is fairly short and does not require intricate algorithms. The emphasis in this task is on:
- understanding the problem to be solved and write a formal specification;
- understanding what Java libraries offer and how to use them;
- documenting your code so that other developers can use it;
- writing tests for your code;
- developing the software as a Agile project;
An example of usage is as follows. In many operating systems, there is a command or script to list all the user’s processes (e.g. ps aux on Unix) in the terminal. Assume you need to collect the set of running processes but programmatically from a Java program. In the Java program, you want to do the following:1
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4// create a process manager to interact with 'ps'
ProcessManager p = new ProcessManager("ps", "aux");
// spawn a process that runs 'ps aux' and collect the result
String res = p.spanwAndCollect();
First sprint
In a first instance, we assume that the program to be run (e.g. ps aux), runs and terminates, and we do not need to collect the result of the output.
Useful Concept for this sprint: ProcessBuilder (Java)
Write the code for the spawn method in the Java class ProcessManager. Can you test that the process is actually created, and properly destroyed (resources released)?
Implement the method destroy(). Can you write tests (using Junit) to test that a process is created and destroyed?
You have to document your code using the JavaDoc 1 standard.
Second sprint
Useful Concept for this sprint: Pipes, InputReader/Writer, BufferedReader/Writer
You have to write the code for the spanwAndCollect method. To do this, you need to connect the input/output streams of the external process to the Java program (ProcessManager).
You have to write the documentation and provide some tests (JUnit). Notice that you may use other external processes to test your implementation (e.g. write your own scripts).
An example usage is as follows:1
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7// create a process manager to interact with 'ps'
ProcessManager p = new ProcessManager("ps", "aux");
// spawn a process and collect the result
String res = p.spanwAndCollect();
// res should contain the list of processes
Third sprint
Add a timeout to the spawnAndCollect method. If the process does not answer before the timeout, an exception should be raised.
An example usage is as follows:1
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8// create a process manager to interact with 'sleepAndEcho'
// where 'sleepAndEcho echoes "DONE" after 3 seconds
ProcessManager p = new ProcessManager("sleepAndEcho", "3");
// spawn a process and collect the result. Timeout 2 seconds
String res = p.spanwAndCollectWithTimeout(2000);
// should raise a timeout exception