Java Program - HashMaps and TreeMaps

• 5th Jun, 2019
• 17:31 PM

Java Program - Question

Remove the linked lists from project 3 and use a HashMap and TreeMap to store the Box objects. Read a line from the input file, instantiate a new Box (check for exceptions), and insert the Box into a HashMap and into a TreeMap.

Print the results of the stored HashMap in the left column of the grid layout, and the results of the stored TreeMap in the right column of the grid layout. The TreeMap results should come out in sorted order.

 

Java Program - Solution

 

Public Class Box
 

public class Box
{
    private int length;
    private int width;
    private int height;

    public Box ()
    {
      
    }
    

    //constructor
    public Box (int l, int w, int h)
    {
        if(l < 1 || w < 1 || h < 1)
        {
            throw new IllegalBoxException("The measurement for the box are invalid ");
        }
        else 
        {
            this.length = l;
            this.width = w;
            this.height = h;
        }
    }

    //set length method
    public void setLength(int l)
    {
        if(l > 0)
        {
            this.length = l;
        }
        else
        {
            this.length = 1;
        }
    }

    //set width method
    public void setWidth(int w)
    {
        if(w > 0)
        {
            width = w;
        }
        else
        {
            width = 1;
        }
    }

    //set height method
    public void setHeight(int h)
    {
        if(h > 0)
        {
            height = h;
        }
        else
        {
            height = 1;
        }
    }

    //calculate volume method
    public int getvolume()
    {
        return length *width *height;
    }
    
    //get length method
    public int getLength()
    {
        return length;
    }
    //get width method
    public int getWidth()
    {
        return width;
    }
    //get height
    public int getHeight()
    {
        return height;
    }

    public String toString()
    {
        return String.format("L: %d, W: %d, H:%d (V: %d)",
                getLength(), getWidth(), getHeight(),getvolume());
    }
}

Box GUI

import java.awt.GridLayout;
import java.util.Map;

import javax.swing.JFrame;

import javax.swing.JTextArea;

@SuppressWarnings("serial")
public class BoxGUI extends JFrame {
    private JTextArea leftTextArea=new JTextArea(10,10);
    private JTextArea rightTextArea=new JTextArea(10,10);

    public BoxGUI(Map hashmap, Map treemap) {

        setTitle("Box");
        setSize(350, 350);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(1, 2,20,20));
        String data = "HASH MAP\n\n"; //Title for Unsorted Boxes
                
                for(Map.Entry entry : hashmap.entrySet()) {
                    data+= entry.getValue().toString() + "\n";
                }
                
        leftTextArea.setText(data);
        add(leftTextArea);
        rightTextArea.setEditable(false);
                
                data = "TREE MAP\n\n";
        for(Map.Entry entry : treemap.entrySet()) {
                    data+= entry.getValue().toString() + "\n";
                }
        rightTextArea.setText(data);
        add(rightTextArea);
        setVisible(true);
        pack();
    }
}

Illegal Box Exception

/**
 *

Title: IllegalBoxException Class

 *
 *

Description: Exception Class for use by all Box classes

 */

@SuppressWarnings("serial")
public class IllegalBoxException extends RuntimeException{
    /**
     * Initializes an ElementNotFoundException storing an appropriate 
     * message along with the type of the collection (as specified by the user).
     */
    public IllegalBoxException (String collection)
    {
        super("The measurement for the box are invalid " + collection);
    }
}

 

Project Solution

 

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Project4
{
    public static void main(String[] args) {
        //the filepath needs to be manually updated depending on the placement of the file and OS
        String filename="/Users/nirav/eclipse-workspace/Project3/boxes.txt";
                //String filename="boxes.txt";
        Scanner filescanner=null;

        String filecontent="";
        int size;
        int i=0;

        try {
            filecontent=readFile(filename,Charset.defaultCharset());
            String rows[]=filecontent.split("\n");
            size = rows.length;
                        
                        Map hashmap = new HashMap<>();
                        Map treemap = new TreeMap<>();

            while(i             {
                            try {
                String data[]=rows[i].trim().split(",");
                int l=Integer.parseInt(data[0]);
                int w=Integer.parseInt(data[1]);
                int h=Integer.parseInt(data[2]);
                                
                Box box = new Box(l,w,h);
                                
                                hashmap.put(box.getvolume(), box);                                
                                treemap.put(box.getvolume(), box);
                            } catch (IllegalBoxException e) {
                                System.out.println(e.getMessage());
                            }
                            
                            i++;
            }
                            
            BoxGUI boxGUI = new BoxGUI(hashmap, treemap);
                        boxGUI.show();

        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
        }

    static String readFile(String path, Charset encoding)
            throws IOException
    {
        byte[] encoded = Files.readAllBytes(Paths.get(path));
        return new String(encoded, encoding);
    }
}