java.util
public class: Stack [javadoc |
source]
java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractList<E>
java.util.Vector<E>
java.util.Stack
All Implemented Interfaces:
Cloneable, List, Serializable, RandomAccess, Collection
The
Stack class represents a last-in-first-out
(LIFO) stack of objects. It extends class
Vector with five
operations that allow a vector to be treated as a stack. The usual
push and
pop operations are provided, as well as a
method to
peek at the top item on the stack, a method to test
for whether the stack is
empty, and a method to
search
the stack for an item and discover how far it is from the top.
When a stack is first created, it contains no items.
A more complete and consistent set of LIFO stack operations is
provided by the Deque interface and its implementations, which
should be used in preference to this class. For example:
{@code
Deque stack = new ArrayDeque();}- author:
Jonathan - Payne
- since:
JDK1.0 -
| Methods from java.util.Vector: |
|---|
|
add, add, addAll, addAll, addElement, capacity, clear, clone, contains, containsAll, copyInto, elementAt, elementData, elements, ensureCapacity, equals, firstElement, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, iterator, lastElement, lastIndexOf, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeAllElements, removeElement, removeElementAt, removeRange, retainAll, set, setElementAt, setSize, size, subList, toArray, toArray, toString, trimToSize |
| Methods from java.util.AbstractList: |
|---|
|
add, add, addAll, clear, equals, get, hashCode, indexOf, iterator, lastIndexOf, listIterator, listIterator, remove, removeRange, set, subList |
| Methods from java.util.AbstractCollection: |
|---|
|
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray, toString |
| Methods from java.lang.Object: |
|---|
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Method from java.util.Stack Detail: |
|---|
 public boolean empty() {
return size() == 0;
}
Tests if this stack is empty. |
public synchronized E peek() {
int len = size();
if (len == 0)
throw new EmptyStackException();
return elementAt(len - 1);
} Looks at the object at the top of this stack without removing it
from the stack. |
public synchronized E pop() {
E obj;
int len = size();
obj = peek();
removeElementAt(len - 1);
return obj;
} Removes the object at the top of this stack and returns that
object as the value of this function. |
public E push(E item) {
addElement(item);
return item;
} Pushes an item onto the top of this stack. This has exactly
the same effect as:
addElement(item)
|
public synchronized int search(Object o) {
int i = lastIndexOf(o);
if (i >= 0) {
return size() - i;
}
return -1;
} Returns the 1-based position where an object is on this stack.
If the object o occurs as an item in this stack, this
method returns the distance from the top of the stack of the
occurrence nearest the top of the stack; the topmost item on the
stack is considered to be at distance 1. The equals
method is used to compare o to the
items in this stack. |
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