compact1, compact2, compact3
java.util
Class Stack<E>
- java.lang.Object
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- java.util.AbstractCollection<E>
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- java.util.AbstractList<E>
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- java.util.Vector<E>
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- java.util.Stack<E>
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- All Implemented Interfaces:
- Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess
public class Stack<E> extends Vector<E>
TheStackclass 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
Dequeinterface and its implementations, which should be used in preference to this class. For example:Deque<Integer> stack = new ArrayDeque<Integer>();- Since:
- JDK1.0
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class java.util.Vector
capacityIncrement, elementCount, elementData
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Fields inherited from class java.util.AbstractList
modCount
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Constructor Summary
Constructors Constructor and Description Stack()Creates an empty Stack.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description booleanempty()Tests if this stack is empty.Epeek()Looks at the object at the top of this stack without removing it from the stack.Epop()Removes the object at the top of this stack and returns that object as the value of this function.Epush(E item)Pushes an item onto the top of this stack.intsearch(Object o)Returns the 1-based position where an object is on this stack.-
Methods inherited from 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, sort, spliterator, subList, toArray, toArray, toString, trimToSize
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Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Collection
parallelStream, stream
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Method Detail
push
public E push(E item)
Pushes an item onto the top of this stack. This has exactly the same effect as:addElement(item)
- Parameters:
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item- the item to be pushed onto this stack. - Returns:
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the
itemargument. - See Also:
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Vector.addElement(E)
pop
public E 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 Vector object).
- Throws:
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EmptyStackException- if this stack is empty.
peek
public E 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 Vector object).
- Throws:
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EmptyStackException- if this stack is empty.
empty
public boolean empty()
Tests if this stack is empty.- Returns:
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trueif and only if this stack contains no items;falseotherwise.
search
public int search(Object o)
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.- Parameters:
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o- the desired object. - Returns:
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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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Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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