Define a class of bags that implements the interface BagInterface, as given in Listing of...

Define a class of bags that implements the interface BagInterface, as given in Listing of Chapter 1, and is a subclass of LinkedChainBase, as given in Listing

LISTING A Java interface for a class of bags

/**An interface that describes the operations of a bag of objects.@author Frank M. Carrano*/public interface BagInterface{  /** Gets the current number of entries in this bag.  @return the integer number of entries currently in the bag */  public int getCurrentSize();  /** Sees whether this bag is full.  @return true if the bag is full, or false if not */  public boolean isFull();  /** Sees whether this bag is empty.  @return true if the bag is empty, or false if not */  public boolean isEmpty();  /** Adds a new entry to this bag.  @param newEntry the object to be added as a new entry  @return true if the addition is successful, or false if not */  public boolean add(T newEntry);  /** Removes one unspecified entry from this bag, if possible.  @return either the removed entry, if the removal  was successful, or null */  public T remove();  /** Removes one occurrence of a given entry from this bag,  if possible.  @param anEntry the entry to be removed  @return true if the removal was successful, or false if not */  public boolean remove(T anEntry);  /** Removes all entries from this bag. */  public void clear();  /** Counts the number of times a given entry appears in this bag.  @param anEntry the entry to be counted  @return the number of times anEntry appears in the bag */  public int getFrequencyOf(T anEntry);  /** Tests whether this bag contains a given entry.  @param anEntry the entry to locate  @return true if the bag contains anEntry, or false otherwise */  public boolean contains(T anEntry);  /** Creates an array of all entries that are in this bag.  @return a newly allocated array of all the entries in the bag */  public T[] toArray();} // end BagInterface

LISTING The abstract base class LinkedChainBase

public abstract class LinkedChainBase{  private Node firstNode; // reference to first node  private int numberOfEntries  public LinkedChainBase()  {  clear();  } // end default constructor   . . .   . . .  protected class Node  {  private T data; // data portion  private Node next; // next to next node  protected Node(T dataPortion)  {  data = dataPortion;  next = null;  } // end constructor  private Node(T dataPortion, Node nextNode)  {  data = dataPortion;  next = nextNode;  } // end constructor   . . .   . . .  } // end Node} // end LinkedChainBase