Java Reference
In-Depth Information
implementations of a class of bags. Code written with respect to an interface allows us to more eas-
ily replace one implementation of a bag with another.
LISTING 1-1
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<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 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 */
