Description
1.1. Homework 7.1 (30 Points)
Objective: Implementing a HashSet using generics and exceptions
Grading:
Correctness: You can lose up to 40% if your solution is not correct
Quality: You can lose up to 80% if your solution is poorly designed
Testing: You can lose up to 50% if your solution is not well tested
Explanation: You can lose up to 100% if your solution if you can not explain your solution during the
grading session
Homework Description:
You hav e to implement a subset of a set Your implementation must allow to insert the null element. Inserting an element must be done based onthe hash value of the element, with the exception of the null element.
Explanation:
Given is the following interface:
1 public interface SetI {
2 boolean add(E e);
3
4 boolean addAll(SetI<? extends E> c);
5 boolean containsAll(SetI<?> c);
6 boolean removeAll(SetI<?> c);
7 void clear();
8 boolean contains(Object o);
9 boolean equals(Object o);
10 int hashCode();
11 boolean isEmpty();
12 boolean remove(Object o);
13 int size();
14 Object[] toArray();
15 // T[] toArray(T[] a); try it, not required
16 }
Source Code: Src/27/SetI.java
You hav e to implement your class to match the following:
Your Work:
It might be useful
• to read the complete documentation before you start to design your solution.
• to understand what a hash value for a given object means.
• to understand what you do if hashcode(o1) == hashcode(o2) and o1 != o2.
• to think about in which order you should develop the methods
• to think about how you will test the methods.
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You can not use any existing Java class for this home work.
Requirements:
You hav e to provide a test environment for your work. You have to name your class MyHashSet.java.
I will test your submission with the following test program:
Example:
An example of a solution execution:
THe following example is a small snippet of my code:
public static void main(String args[] ) {
SetI aSet = new MyHashSet();
SetI bSet = new MyHashSet();
String[] aStrings = { “a”, “b”, “c” };
String[] bStrings = { “A”, “B”, “C” };
aSet.add(aStrings[0]); aSet.add(aStrings[1]); // setup a, b
bSet.add(bStrings[0]); bSet.add(bStrings[1]); // setup A, B
System.out.println(“aSet = ” + aSet ); // –> a, b
for (int index = 0; index < aStrings.length; index ++ ) { // contans a and bSystem.out.println(“does ” + ( aSet.contains(aStrings[index]) ? “” : ” not ” ) + “contaaStrings[index] ); } System.out.println(“aSet = ” + aSet ); // –> a, b
System.out.println(“aSet.remove(aStrings[0]); = ” + aSet.remove(aStrings[0]) ); //System.out.println(“aSet.remove(aStrings[2]); = ” + aSet.remove(aStrings[2]) ); //System.out.println(“aSet = ” + aSet );
aSet.addAll(bSet); // –> b, A, B
System.out.println(“aSet = ” + aSet );
aSet.add(null); // –> b, A, B, null
System.out.println(“aSet = ” + aSet );
System.out.println(“aSet.remove(null); = ” + aSet.remove(null) ); // can rem}
This code aboive produces the following output:
% java TestMyHashSet
aSet = 0: 0/null 1/null 2/null
1: 0/null 1/null 2/null
2: 0/null 1/null 2/null
3: 0/null 1/null 2/null
4: 0/null 1/null 2/null
5: 0/null 1/null 2/null
6: 0/null 1/null 2/null
7: 0/a 1/null 2/null
8: 0/b 1/null 2/null
9: 0/null 1/null 2/null
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does contain: a
does contain: b
does not contain: c
aSet = 0: 0/null 1/null 2/null
1: 0/null 1/null 2/null
2: 0/null 1/null 2/null
3: 0/null 1/null 2/null
4: 0/null 1/null 2/null
5: 0/null 1/null 2/null
6: 0/null 1/null 2/null
7: 0/a 1/null 2/null
8: 0/b 1/null 2/null
9: 0/null 1/null 2/null
aSet.remove(aStrings[0]); = true
aSet.remove(aStrings[2]); = false
aSet = 0: 0/null 1/null 2/null
1: 0/null 1/null 2/null
2: 0/null 1/null 2/null
3: 0/null 1/null 2/null
4: 0/null 1/null 2/null
5: 0/null 1/null 2/null
6: 0/null 1/null 2/null
7: 0/null 1/null 2/null
8: 0/b 1/null 2/null
9: 0/null 1/null 2/null
aSet = 0: 0/null 1/null 2/null
1: 0/null 1/null 2/null
2: 0/null 1/null 2/null
3: 0/null 1/null 2/null
4: 0/null 1/null 2/null
5: 0/A 1/null 2/null
6: 0/B 1/null 2/null
7: 0/null 1/null 2/null
8: 0/b 1/null 2/null
9: 0/null 1/null 2/null
aSet = null 0: 0/null 1/null 2/null
1: 0/null 1/null 2/null
2: 0/null 1/null 2/null
3: 0/null 1/null 2/null
4: 0/null 1/null 2/null
5: 0/A 1/null 2/null
6: 0/B 1/null 2/null
7: 0/null 1/null 2/null
8: 0/b 1/null 2/null
9: 0/null 1/null 2/null
9: null
aSet.remove(null); = true
Submission:
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% ssh glados.cs.rit.edu # or use queeg.cs.rit.edu if glados is down
# password
# go to the directory where your solution is …
% try hpb-grd lab7-1 ’All files required’
# you can see if your submission was successful:
# try -q hpb-grd lab7-1
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