Package com.aspectran.utils

Class ArrayStack<E>

java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractList<E>
java.util.ArrayList<E>
com.aspectran.utils.ArrayStack<E>
Type Parameters:
E - the type of elements in this list
All Implemented Interfaces:
Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess
public class ArrayStack<E> extends ArrayList<E>

This class is a clone of org.apache.commons.collections4.ArrayStack

An implementation of the Stack API that is based on an ArrayList instead of a Vector, so it is not synchronized to protect against multi-threaded access. The implementation is therefore operates faster in environments where you do not need to worry about multiple thread contention.

The removal order of an ArrayStack is based on insertion order: The most recently added element is removed first. The iteration order is not the same as the removal order. The iterator returns elements from the bottom up, whereas the pop() method removes them from the top down.

Unlike Stack, ArrayStack accepts null entries.

See Also:

  • Constructor Details

    • ArrayStack

      public ArrayStack()
      Constructs a new empty ArrayStack. The initial size is controlled by ArrayList and is currently 10.

    • ArrayStack

      public ArrayStack(int initialSize)
      Constructs a new empty ArrayStack with an initial size.
      Parameters:
      initialSize - the initial size to use
      Throws:
      IllegalArgumentException - if the specified initial size is negative

  • Method Details

    • peek

      public E peek() throws EmptyStackException
      Returns the top item off of this stack without removing it.
      Returns:
      the top item on the stack
      Throws:
      EmptyStackException - if the stack is empty

    • peek

      public E peek(int n) throws EmptyStackException
      Returns the n'th item down (zero-relative) from the top of this stack without removing it.
      Parameters:
      n - the number of items down to go
      Returns:
      the n'th item on the stack, zero relative
      Throws:
      EmptyStackException - if there are not enough items on the stack to satisfy this request

    • peek

      public E peek(Class<?> target) throws EmptyStackException
      Throws:
      EmptyStackException

    • pop

      public E pop() throws EmptyStackException
      Pops the top item off of this stack and return it.
      Returns:
      the top item on the stack
      Throws:
      EmptyStackException - if the stack is empty

    • push

      public E push(E item)
      Pushes a new item onto the top of this stack. The pushed item is also returned. This is equivalent to calling add.
      Parameters:
      item - the item to be added
      Returns:
      the item just pushed

    • update

      public E update(E item) throws EmptyStackException
      Replaces the top item of this stack with another item without removing it.
      Returns:
      the top item previously on the stack
      Throws:
      EmptyStackException - if the stack is empty

    • update

      public E update(int n, E item) throws EmptyStackException
      Replaces the n'th item down (zero-relative) from the top of this stack with another item without removing it.
      Parameters:
      n - the number of items down to go
      Returns:
      the n'th item previously on the stack, zero relative
      Throws:
      EmptyStackException - if there are not enough items on the stack to satisfy this request

    • search

      public int search(E object)
      Returns the one-based position of the distance from the top that the specified object exists on this stack, where the top-most element is considered to be at distance 1. If the object is not present on the stack, return -1 instead. The equals() method is used to compare to the items in this stack.
      Parameters:
      object - the object to be searched for
      Returns:
      the 1-based depth into the stack of the object, or -1 if not found