Directory:Derek Elder/Programs/ReverseGraph

//Program 1b
//Professor Pattis, ICS-23 Lab 1
//Programmers: Cameron Ruatta, Derek Elder

import edu.uci.ics.pattis.introlib.Prompt;
import edu.uci.ics.pattis.introlib.TypedBufferReader;
import edu.uci.ics.pattis.ics23.collections.*;

import java.util.StringTokenizer;
import java.io.EOFException;
import java.util.Arrays;

public class Reverse
{
	public static void printGraph(Map<String,Set<String>> graphMap, String output)
	{
		System.out.println(output);
		List<String> sourceNodesList = new ArrayList<String>(graphMap.keys());
		Collections.sort(sourceNodesList);
		for(String sourceNode : sourceNodesList)
		{
			Set<String> destinationNodes = graphMap.get(sourceNode);
			System.out.println(sourceNode + " -> " + destinationNodes);
		}
	}
	public static Map<String,Set<String>> reverse(Map<String,Set<String>> graphMap)
	{
		Map<String,Set<String>> reverseMap = new ArrayMap<String,Set<String>>();
		for(String newValue : graphMap.keys()) //Go through old keys (new values)
		{
			for(String newKey : graphMap.get(newValue)) //Go through old values (new keys)
			{
				Set<String> nodes = reverseMap.get(newKey);
				if (nodes == null)
				{
					nodes = new ArraySet<String>();
					reverseMap.put(newKey,nodes);
				}
				nodes.add(newValue);
			}
		}
		return reverseMap;
	}
	public static void main(String[] args)
	{
		Map<String,Set<String>> graphMap = new ArrayMap<String,Set<String>>();
		TypedBufferReader tbr = new TypedBufferReader("Enter name of file with graph");
		//Repeatedly read lines from a file until the EOFException is thrown.
		for (;;)
		{
			try
			{
				String line = tbr.readLine();
				StringTokenizer st = new StringTokenizer(line, ";");
				String sourceNode = st.nextToken();
				
				while (st.hasMoreTokens())
				{
					String token = st.nextToken();

					//Update map for the current node
					Set<String> nodes = graphMap.get(sourceNode);
					if (nodes == null)
					{
						nodes = new ArraySet<String>();
						graphMap.put(sourceNode,nodes);
					}
					nodes.add(token);
				}
			} catch (EOFException e) {break;}
		}
		printGraph(graphMap, "Graph: source -> {destination} edges");
		printGraph(reverse(graphMap), "Reverse Graph: source -> {destination} edges");
	}
}