Package cpsc331.collections

Interface Set<E>

All Known Subinterfaces:

OrderedSet<E>

All Known Implementing Classes:

ChainHashSet, OpenHashSet

public interface Set<E>

Provides an interface for a set whose elements have type E.

Set Invariant: A finite set of non-null elements of type E is maintained.

Method Summary

Modifier and Type	Method	Description
boolean	contains(E e)	Reports whether a given element belongs to this set.
void	include(E e)	Adds an input element to this set, throwing an ElementFoundException if this element already belongs to it.
void	remove(E e)	Removes an input element to this set, throwing a NoSuchElementException if this element does not belong to it.

Method Detail

contains

boolean contains(E e)
          throws java.lang.NullPointerException

Reports whether a given element belongs to this set.

Parameters:

e - the element to be searched for

Returns:

true if this element is found; false otherwise

Precondition:

1. The Set Invariant is satisfied.
2. A value e with type E has been given as input.

Postcondition:

1. The Set Invariant is satisfied.
2. This set has not been changed.
3. If the given element e is null then a NullPointerException is thrown.
4. Otherwise (that is, if the given element is not null), if the given element e belongs to this set then “true” is returned; “false” is returned otherwise.

Throws:

java.lang.NullPointerException - if the given element is null

include

void include(E e)
      throws java.lang.NullPointerException,
             ElementFoundException

Adds an input element to this set, throwing an ElementFoundException if this element already belongs to it.

Parameters:

e - the element to be added to this set

Throws:

java.lang.NullPointerException - if the given element is null

ElementFoundException - if this element is not null but is already in the set

Precondition:

1. The Set Invariant is satisfied.
2. A value e with type E has been given as input.

Postcondition:

1. The Set Invariant is satisfied.
2. If the input element is null then a NullPointerException is thrown.
3. Otherwise (that is, if the input element is not null), if the input element e was not already included in this set then e has been added to it, and no other changes have been made. An ElementFoundException is thrown, otherwise, and this set has not been changed.

remove

void remove(E e)
     throws java.lang.NullPointerException,
            java.util.NoSuchElementException

Removes an input element to this set, throwing a NoSuchElementException if this element does not belong to it.

Parameters:

e - the element to be removed from this set

Throws:

java.lang.NullPointerException - if the given element is null

java.util.NoSuchElementException - if this element was not in this set

Precondition:

1. The Set Invariant is satisfied.
2. A value e with type E has been given as input.

Postcondition:

1. The Set Invariant is satisfied.
2. If the input element is null then a NullPointerException is thrown.
3. Otherwise (that is, if the given element is null), if the input element e was already included in this set then this element is removed from it. A NoSuchElementException is thrown otherwise, and this set is not changed.