interface StackInterfaceHw$2.$java:$$

$$

$$

$/**$

return without removing the oldest$$ element that was added to the stack; if stack is empty then return null.

Example, If we had push$($A$)$; push$($C$)$; push$($R$)$; push$($W$)$; the top of stack would be W$,$ then if we call peekOldest$()$ it would return $$A$$ and stack remains as is unchanged, ACRW &$$ W is still top of stack.

@return the oldest data entered into the stack, without deleting the data from the stack

$*/$

public T peekOldest$()$;

$$

$$

$/**$

swap the most recent element in the stack $($top of stack$)$ with the oldest element added to the stack and return True. If stack is empty return false.

Example, if the stack has A$,$B$,$C$,$D and top of stack is D then after calling swap$()$ the stack would have D$,$B$,$C$,$A with A being the top of stack

@return false: stack is empty

$$true: exchanged top of stack with bottom of stack $,$ so top of stack has$$

$$ become bottom of stack and bottom of stack has become top of stack

$*/$

public boolean swap$()$;

$$

$$

$/**$

This method searches stack for the given object t; if found, true is returned else false is returned.

@param t the object to search for

@return true if t is in the stack otherwise return false

$*/$

public boolean search$($T t$)$;

public interface StackInterfaceHW$2\{$

$/**$

return without removing the oldest element that was added to the stack; if stack is empty then return null.

Example, If we had push$($A$)$; push$($C$)$; push$($R$)$; push$($W$)$; the top of stack would be W$,$ then if we call peekOldest$()$ it would return $$A$$ and stack remains as is unchanged, ACRW & W is still top of stack.

@return the oldest data entered into the stack, without deleting the data from the stack

$*/$

public T peekOldest$()$;

$/**$

swap the most recent element in the stack $($top of stack$)$ with the oldest element added to the stack and return True. If stack is empty return false.

Example, if the stack has A$,$B$,$C$,$D and top of stack is D then after calling swap$()$ the stack would have D$,$B$,$C$,$A with A being the top of stack

@return false: stack is empty

true: exchanged top of stack with bottom of stack $,$ so top of stack has

become bottom of stack and bottom of stack has become top of stack

$*/$

public boolean swap$()$;

$/**$

This method searches stack for the given object t; if found, true is returned else false is returned.

@param t the object to search for

@return true if t is in the stack otherwise return false

$*/$

public boolean search$($T t$)$;

$/**$ Adds a new entry to the top of this stack.

@param newEntry An object to be added to the stack. $*/$

public void push$($T newEntry$)$;

$/**$ Removes and returns this stack's top entry.

@return The object at the top of the stack.

@throws EmptyStackException if the stack is empty before the operation. $*/$

public T pop$()$;

$/**$ Retrieves this stack's top entry.

@return The object at the top of the stack.

@throws EmptyStackException if the stack is empty. $*/$

public T peek$()$;

$/**$ Detects whether this stack is empty.

@return True if the stack is empty. $*/$

public boolean isEmpty$()$;

$/**$ Removes all entries from this stack. $*/$

public void clear$()$;

$\}//$ end StackInterface

A$.$ LinkedStackHW$2$

What I want you to do for this homework is to modify class LinkedStack and rename it to be $$LinkedStackHW$2.$java $$and have it implement the new interface StackInterfaceHw$2.$

So LinkedStackHW$2$ will have everything LinkedStack had before and in addition it will implement the $3$ new methods in the interface,

$$

$1.$ public T peekOldest$()$;

$$

$2.$public boolean swap$()$;

$$

$3.$public boolean search$($T t$)$;

$$

$$

$$

B$.$ Main method in LinkedStackHW$2$

$$

To test that your methods in class LinkedStackHW$2$ are implemented correctly, I want you to write several test cases, to test each of the $3$ methods; at a minimum, do the following tests and print out their results to the screen.

B$1.1$ test peekOldest with stack having data

B$2.1$ test peekOldest with stack empty

B$3.1$ test for swap

B$41$ test for search with searchItem in the stack

B$51$ test for search with searchItem not in the stack