Class Stack<E>
java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractList<E>
java.util.Vector<E>
java.util.Stack<E>
- Type Parameters:
E- Type of component elements
- All Implemented Interfaces:
Serializable,Cloneable,Iterable<E>,Collection<E>,List<E>,RandomAccess,SequencedCollection<E>
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:
Deque<Integer> stack = new ArrayDeque<Integer>();- Since:
- 1.0
- See Also:
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Field Summary
Fields declared in class java.util.Vector
capacityIncrement, elementCount, elementDataFields declared in class java.util.AbstractList
modCount -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionbooleanempty()Tests if this stack is empty.peek()Looks at the object at the top of this stack without removing it from the stack.pop()Removes the object at the top of this stack and returns that object as the value of this function.Pushes an item onto the top of this stack.intReturns the 1-based position where an object is on this stack.Methods declared in class java.util.Vector
add, add, addAll, addAll, addElement, capacity, clear, clone, contains, containsAll, copyInto, elementAt, elements, ensureCapacity, equals, firstElement, forEach, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, iterator, lastElement, lastIndexOf, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeAllElements, removeElement, removeElementAt, removeIf, removeRange, replaceAll, retainAll, set, setElementAt, setSize, size, spliterator, subList, toArray, toArray, toString, trimToSizeMethods declared in interface java.util.Collection
parallelStream, stream, toArrayMethods declared in interface java.util.List
addFirst, addLast, getFirst, getLast, removeFirst, removeLast, reversed, sort
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Constructor Details
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Stack
public Stack()Creates an empty Stack.
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Method Details
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push
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pop
Removes the object at the top of this stack and returns that object as the value of this function.- Returns:
- The object at the top of this stack (the last item
of the
Vectorobject). - Throws:
EmptyStackException- if this stack is empty.
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peek
Looks at the object at the top of this stack without removing it from the stack.- Returns:
- the object at the top of this stack (the last item
of the
Vectorobject). - Throws:
EmptyStackException- if this stack is empty.
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empty
public boolean empty()Tests if this stack is empty.- Returns:
trueif and only if this stack contains no items;falseotherwise.
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search
Returns the 1-based position where an object is on this stack. If the objectooccurs 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 distance1. Theequalsmethod is used to compareoto the items in this stack.- Parameters:
o- the desired object.- Returns:
- the 1-based position from the top of the stack where
the object is located; the return value
-1indicates that the object is not on the stack.
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