structure
Class AbstractStack
java.lang.Object
structure.AbstractStructure
structure.AbstractLinear
structure.AbstractStack
- All Implemented Interfaces:
- Linear, Stack, Structure
- Direct Known Subclasses:
- StackArray, StackList, StackVector
public abstract class AbstractStack
- extends AbstractLinear
- implements Stack
An abstract structure describing a Last-In, First-Out structure.
Stacks are typically used to store the state of a recursively
solved problem.
Method Summary |
java.lang.Object |
getFirst()
Deprecated. Please use method get, rather than getFirst! |
java.lang.Object |
peek()
Fetch a reference to the top element of the stack. |
java.lang.Object |
pop()
Remove an element from the top of the stack. |
void |
push(java.lang.Object item)
Add an element from the top of the stack. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
AbstractStack
public AbstractStack()
push
public void push(java.lang.Object item)
- Add an element from the top of the stack.
- Specified by:
push
in interface Stack
- Parameters:
item
- The element to be added to the stack top.- Postcondition:
- item is added to stack
will be popped next if no intervening add
pop
public java.lang.Object pop()
- Remove an element from the top of the stack.
- Specified by:
pop
in interface Stack
- Returns:
- The item removed from the top of the stack.
- Precondition:
- stack is not empty
- Postcondition:
- most recently added item is removed and returned
getFirst
public java.lang.Object getFirst()
- Deprecated. Please use method get, rather than getFirst!
- Fetch a reference to the top element of the stack.
- Specified by:
getFirst
in interface Stack
- Returns:
- A reference to the top element of the stack.
- Precondition:
- stack is not empty
- Postcondition:
- top value (next to be popped) is returned
peek
public java.lang.Object peek()
- Fetch a reference to the top element of the stack.
Provided for compatibility with java.util.Stack.
- Specified by:
peek
in interface Stack
- Returns:
- A reference to the top element of the stack.
- Precondition:
- stack is not empty
- Postcondition:
- top value (next to be popped) is returned