hlt.language.util

Class Stack

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList

hlt.language.util.ArrayList

hlt.language.util.Stack

All Implemented Interfaces:

ViewableStack, java.lang.Iterable, java.util.Collection, java.util.List

Direct Known Subclasses:

Enclosure, ParameterStack

public class Stack
extends ArrayList
implements ViewableStack

This class implements an unsynchronized Stack. It has the exact same API as that of java.util.Stack and one may use this in its stead when one does not want to pay the price of mutex synchronization and unneeded range check overhead for every stack operation. In addition, it adds two new constructors that allow to specify the stack's initial capacity.

Constructor Summary

Constructors

Constructor and Description
Stack() Constructs an empty Stack.
Stack(int initialCapacity) Constructs an empty stack with the specified initial capacity and with its capacity increment equal to zero.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	empty() Tests if this stack is empty.
java.util.Iterator	iterator() Returns an iterator for this Stack.
java.lang.Object	peek() Looks at the object at the top of this stack without removing it from the stack.
java.lang.Object	peek(int n) Peeks at n positions from the top of the stack.
java.lang.Object	pop() Removes the object at the top of this stack and returns that object as the value of this function.
java.lang.Object	push(java.lang.Object item) Pushes an item onto the top of this stack.
java.lang.Object	replace(int n, java.lang.Object newObject) Replaces the object at n positions from the top of the stack with a new one; returns the old object.
int	search(java.lang.Object o) Returns the 1-based position where an object is on this stack.

Methods inherited from class hlt.language.util.ArrayList

add, add, addAll, addAll, addAll, addAll, addElement, capacity, clear, clear, clone, contains, containsAll, containsAll, copyInto, elementAt, ensureCapacity, equals, firstElement, get, hasGaps, hashCode, indexOf, indexOf, insertElementAt, isEmpty, lastElement, lastIndexOf, lastIndexOf, remove, remove, removeAll, removeAll, removeAllElements, removeAllFirst, removeAllFirst, removeElement, removeElementAt, removeGaps, removeRange, retainAll, set, setElementAt, setIncrementFactor, setLast, setSize, size, toArray, toString, toStringArray, trimToSize

Methods inherited from class java.util.AbstractList

addAll, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, removeAll, retainAll, toArray

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface hlt.language.util.ViewableStack

get, isEmpty, size

Methods inherited from interface java.util.Collection

addAll, containsAll, removeAll, retainAll, toArray

Methods inherited from interface java.util.List

addAll, containsAll, removeAll, retainAll, toArray

Constructor Detail

Stack

public Stack()

Constructs an empty Stack.

Stack

public Stack(int initialCapacity)

Constructs an empty stack with the specified initial capacity and with its capacity increment equal to zero.

Parameters:

initialCapacity - the initial capacity of the stack.

Throws:

java.lang.IllegalArgumentException - if the specified initial capacity is negative.

Method Detail

push

public final java.lang.Object push(java.lang.Object item)

Pushes an item onto the top of this stack. This has exactly the same effect as: add(item).

Parameters:

item - the item to be pushed onto this stack.

Returns:

the item argument.

pop

public final java.lang.Object 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.

Throws:

java.lang.ArrayIndexOutOfBoundsException - if this stack is empty.

peek

public final java.lang.Object peek()

Looks at the object at the top of this stack without removing it from the stack.

Specified by:

peek in interface ViewableStack

Returns:

the object at the top of this stack.

Throws:

java.lang.ArrayIndexOutOfBoundsException - if this stack is empty.

peek

public final java.lang.Object peek(int n)

Peeks at n positions from the top of the stack.

Parameters:

n - the offset from the top (0 -> top, 1 -> top-1,...)

Throws:

java.lang.ArrayIndexOutOfBoundsException - if index out of range.

replace

public final java.lang.Object replace(int n,
                       java.lang.Object newObject)

Replaces the object at n positions from the top of the stack with a new one; returns the old object.

Parameters:

n - the offset from the top (0 -> top, 1 -> top-1,...)

newObject - the new object

Returns:

the old object at that position

Throws:

java.lang.ArrayIndexOutOfBoundsException - if index out of range.

empty

public final boolean empty()

Tests if this stack is empty.

Returns:

true iff this contains no items; false otherwise.

search

public final int search(java.lang.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:

o - the desired object.

Returns:

the 1-based position of the object from the top, or -1 if not found.

iterator

public java.util.Iterator iterator()

Returns an iterator for this Stack. The stack elements are visited from newest to oldest.

Specified by:

iterator in interface ViewableStack

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in interface java.util.List

Overrides:

iterator in class ArrayList