CEJavaProgAssignment

/*
*  Programming Assignment 1
*  Author : Wang Yee Lin Pamela, Tan Jun Hui Augustine
∗ ID: 1002367, 1002158
∗ Date: 03/03/2018
*
* */

Purpose of the program

The purpose of this program is to execute a group of programs that have control and data dependencies on each other in the correct order.

How to compile

To compile this program, place the testing instruction set and the test files in the same folder as the .java files provided and compile using: javac *.java

How the program works

First it will set the current working directory, then it will set the instruction set to testproc.txt as per the default code given.

Next the program will parse the file and populate the data structure as provided, according to the instruction set from the testproc.txt in the same folder.

Next the program will set up the parent pointers for every node in the data structure. Before printing out the graph information.

Process builder is initialized and it's directory is set to the current directory. An arraylist is initialized for the list of runnable nodes

A boolean variable, allE is used to check if all nodes are executed. It controls a while loop that keeps executing the following set of actions as long as all nodes are not executed.

set the list of runnable nodes to all nodes that are currently runnable (parents have been executed and the node itself has not been executed before.
for every node in the runnable list, redirect the input and output of the node if required (if it isn't stdin or stdout) and run the command, starting the process. Wait if neccessary. Then set the current node as having been executed.
set allE to the boolean of whether all nodes have been executed

Once it is done print out the graph again.

Explaining the functions

myParentExecuted

Here is a function to check all parents have been executed

    public boolean myParentExecuted() {
        boolean ans = true;
        for (ProcessGraphNode parent : this.getParents()) {
            if (!parent.isExecuted())
                ans = false;
        }

        return ans;
    }

areAllExecuted

Here is a function to check if all nodes have been executed

private static boolean areAllExecuted() {
        boolean aE = true;
        for(ProcessGraphNode a : ProcessGraph.nodes){
            if(a.isExecuted() == false){
                aE = false;
            }
        }
        return aE;
    }

setRunnables

Here is a function that returns all runnable nodes Nodes are deemed to be runnable if their parent nodes have all been executed and they have not been executed before.

    private static ArrayList<ProcessGraphNode> setRunnables() {
        ArrayList<ProcessGraphNode> listToRun = new ArrayList<>();
        for(ProcessGraphNode a : ProcessGraph.nodes){
            if(a.myParentExecuted() && a.isExecuted() == false){
                a.setRunnable();
                listToRun.add(a);
            }else{
                a.setNotRunable();
            }
        }
        return listToRun;
    }

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