mainUI.java

import java.io.*;
import java.util.*;

public class mainUI {

    // Retrieve data to the end of the line as an argument for a method call
    // Include two special kinds of arguments:
    //   "null" asks us to return no string
    //   "empty" asks us to return an empty string

    private static String getEndingString(Scanner userInput ) {
        String userArgument = null;

        userArgument = userInput.nextLine();
        userArgument = userArgument.trim();

        // Include a "hack" to provide null and empty strings for testing
        if (userArgument.equalsIgnoreCase("empty")) {
            userArgument = "";
        } else if (userArgument.equalsIgnoreCase("null")) {
            userArgument = null;
        }

        return userArgument;
    }

    // Main program to process user commands.
    // This method is not robust.  When it asks for a command, it expects all arguments to be there.
    // It is a quickly-done test harness rather than a full solution for an assignment.

    public static void main(String[] args) {
        // Command options

        String addCommand = "add";
        String findCommand = "find";
        String resetCommand = "reset";
        String printCommand = "print";
        String quitCommand = "quit";

        // Define variables to manage user input

        String userCommand = "";
        String userArgument = "";
        Scanner userInput = new Scanner( System.in );

        // Define the recommender that we will be testing.

        SearchTree theTree = new SearchTree();

        // Define variables to catch the return values of the methods

        boolean booleanOutcome;
        Integer findOutcome;

        // Let the user know how to use this interface

        System.out.println("Commands available:");
        System.out.println("  " + addCommand + " <string to the end of line>");
        System.out.println("  " + findCommand + " <string to the end of line>");
        System.out.println("  " + resetCommand );
        System.out.println("  " + printCommand );
        System.out.println("  " + quitCommand);

        // Process the user input until they provide the command "quit"

        do {
            // Find out what the user wants to do
            userCommand = userInput.next();

            /* Do what the user asked for. */

            if (userCommand.equalsIgnoreCase(addCommand)) {
                // Get the parameters.

                userArgument = getEndingString( userInput );

                // Call the method

                booleanOutcome = theTree.add( userArgument );
                System.out.println(userCommand + " \""+userArgument+"\" outcome " + booleanOutcome );
            } else if (userCommand.equalsIgnoreCase(findCommand)) {
                // Get the parameters.

                userArgument = getEndingString( userInput );

                // Call the method

                findOutcome = theTree.find( userArgument );
                System.out.println(userCommand + " \""+userArgument+"\" outcome " + findOutcome );
            } else if (userCommand.equalsIgnoreCase(resetCommand)) {
                // Clear the rest of the line text.

                userArgument = getEndingString( userInput );

                // Call the method

                theTree.reset( );
                System.out.println(userCommand + " \""+userArgument+"\"" );
            } else if (userCommand.equalsIgnoreCase(printCommand)) {
                // Clear the rest of the line text.

                userArgument = getEndingString( userInput );

                // Call the method
                String treeStructure;
                treeStructure = theTree.printTree( );
                System.out.println(userCommand + " \""+userArgument+"\" outcome " );
                System.out.println(treeStructure);
            } else if (userCommand.equalsIgnoreCase(quitCommand)) {
                System.out.println ( userCommand );
            } else {
                System.out.println ("Bad command: " + userCommand);
            }
        } while (!userCommand.equalsIgnoreCase("quit"));

        // The user is done so close the stream of user input before ending.

        userInput.close();
    }
}