package bag;
/**
An interface that describes the operations of a bag of objects.
A bag is an unordered collection of objects of a particular types.
Duplicates are allowed.
@author Frank M. Carrano
@author Timothy M. Henry
@author Margaret Ellis
@version April 2020
*/
public interface BagInterface<T>
{
/** 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 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.
        @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 if not. */
public boolean contains(T anEntry);

/** Retrieves all entries that are in this bag.
   @param values  An array of generics to be filled with bag contents, if
           not large enough will throw ArrayIndexOutOfBoundsException
   @return  The values array filled with the entries in the bag.
       Note: If the bag is empty, the array is returned unmodified */
public T[] toArray(T[] values);


} // end BagInterface