Question

Complete ArrayCollection.java with following methods (Please complete code in java language):

public ArrayCollection();

public ArrayCollection(int size);

public boolean isEmpty();

public boolean isFull();

public int size(); // Return number of elements in the Collection.

public String toString();

public boolean add(T element); // Add an element into the Collection, return true if successful

public boolean remove(T target); // Remove the target from Collection, return true if successful

public boolean removeAll(T target); // Remove all occurrences of Target, return if successful

public void removeDuplicate(); // Remove duplicated element(s)

public boolean equals(ArrayCollection that); // Return true if this Collection is same as that Collection

public int count(T target); // Return the number of a given target in the Collection

public void merge(ArrayCollection that); // Merge this Collection with that Collection

public void enlarge(int size); //Increase this Collection with additional size elements

public void clear(); // Clear entire Collection

public boolean contains(T target); // Return true if the target is in the Collection

public int findIndex(T target); // Return index of the target

package Homework3;

public class ArrayCollection<T> {

protected static final int DEFAULT_CAPACITY = 100;

protected T[] elements;

protected int numberOfElements;

public ArrayCollection() {

this(DEFAULT_CAPACITY);

}

public ArrayCollection(int size) {

elements = (T[]) new Object[size];

numberOfElements = 0;

}

public boolean isEmpty() {

return numberOfElements == 0;

}

public boolean isFull() {

return numberOfElements == elements.length;

}

public int size() {

return numberOfElements;

}

public String toString() {

String collection = "";

for (int i = 0; i < numberOfElements; i++)

collection += elements[i] + "\n";

return collection;

}

public boolean add(T element) {

// Complete your code here

return true;

}

public boolean remove(T target) {

// Complete your code here

return true;

}

public boolean removeAll(T target) {

// Complete your code here

return true;

}

public void removeDuplicate() {

// Remove any duplicated elements

}

public boolean equals(ArrayCollection that) {

// Return true if ArrayCollection are identical.

boolean result = true;

// Complete your code here.

return result && this.size() == that.size();

}

public int count(T target) {

// Return count of target occurrences

int c = 0;

// Complete your code here

return c;

}

public void merge(ArrayCollection that) {

// Merge that ArrayCollection into this ArrayCollection

// Complete your code here

}

public void enlarge(int size) {

// Enlarge elements[] with additional size

// Complete your code here

}

public void clear() {

// Remove all elements in the collection

}

//Note: Different from textbook, this implementation has no 'found' and

'location' attributes.

// There is no find() method.

// There is a new methods findIndex().

public boolean contains(T target) {

// Return true if target is found

boolean found = false;

// Complete your code here

return found;

}

public int findIndex(T target) {

// Return index of target

int index = 0;

// Complete your code here

return index;

}

}

Answer 1

package Homework3;

public class ArrayCollection<T> {

   protected static final int DEFAULT_CAPACITY = 100;

   protected T[] elements;

   protected int numberOfElements;

   public ArrayCollection() {

       this(DEFAULT_CAPACITY);

   }

   public ArrayCollection(int size) {

       elements = (T[]) new Object[size];

       numberOfElements = 0;

   }

   public boolean isEmpty() {

       return numberOfElements == 0;

   }

   public boolean isFull() {

       return numberOfElements == elements.length;

   }

   public int size() {

       return numberOfElements;

   }

   public String toString() {

       String collection = "";

       for (int i = 0; i < numberOfElements; i++)

           collection += elements[i] + "\n";

       return collection;

   }

   public boolean add(T element) {
       if(isFull())
           enlarge(size());
       elements[numberOfElements] = element;
       numberOfElements++;
       return true;

   }

   public boolean remove(T target) {
       int index = findIndex(target);
       if(index == -1)
           return false; //not found

       //shift other elements
       for(int i = index + 1; i < numberOfElements; i++)
           elements[i-1] = elements[i];
       return true;

   }

   public boolean removeAll(T target) {
       if(contains(target)) {
           while(contains(target))
               remove(target);

           return true;
       }
       else
           return false;

   }

   public void removeDuplicate() {
       T[] temp = (T[]) (new Object[numberOfElements]);
       int n = 0;
       int i = 0, j = 0;

       while(i < numberOfElements) {
           boolean dup = false;
           for(int k = 0; k < i; k++) {
               if(elements[k].equals(elements[i])) {
                   dup = true;
                   break;
               }
           }
           if(!dup) {
               temp[j++] = elements[i];
               n++;
           }
           i++;
       }
       elements = temp;
       numberOfElements = n;
   }

   public boolean equals(ArrayCollection that) {

       // Return true if ArrayCollection are identical.

       boolean result = true;

       if(size() != that.size())
           result = false;
       else {
           for(int i = 0; i < size(); i++) {
               if(!elements[i].equals(that.elements[i])) {
                   result = false;
                   break;
               }
           }
       }
       return result && this.size() == that.size();

   }

   public int count(T target) {

       // Return count of target occurrences

       int c = 0;
       for(int i = 0; i < size(); i++) {
           if(elements[i].equals(target)) {
               c++;
           }
       }

       return c;

   }

   public void merge(ArrayCollection<T> that) {

       // Merge that ArrayCollection into this ArrayCollection
       for(int i = 0; i < that.size(); i++) {
           add(that.elements[i]);
       }
   }

   public void enlarge(int size) {

       // Enlarge elements[] with additional size
       T[] temp = (T[]) new Object[elements.length + size];
       for(int i = 0; i < numberOfElements; i++)
           temp[i] = elements[i];
       elements = temp;
   }

   public void clear() {

       // Remove all elements in the collection
       numberOfElements = 0;

   }

   //Note: Different from textbook, this implementation has no 'found' and 'location' attributes.
   // There is no find() method.
   // There is a new methods findIndex().

   public boolean contains(T target) {

       // Return true if target is found

       boolean found = false;

       for(int i = 0; i < size(); i++) {
           if(elements[i].equals(target)) {
               found = true;
               break;
           }
       }
       return found;

   }

   public int findIndex(T target) {

       // Return index of target

       int index = -1;

       for(int i = 0; i < size(); i++) {
           if(elements[i].equals(target)) {
               index = i;
               break;
           }
       }
       return index;

   }

}