+++ /dev/null
-/* Stack.java - Class that provides a Last In First Out (LIFO)
- datatype, known more commonly as a Stack
- Copyright (C) 1998, 1999, 2001, 2004, 2005
- Free Software Foundation, Inc.
-
-This file is part of GNU Classpath.
-
-GNU Classpath is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
-
-GNU Classpath is distributed in the hope that it will be useful, but
-WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with GNU Classpath; see the file COPYING. If not, write to the
-Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301 USA.
-
-Linking this library statically or dynamically with other modules is
-making a combined work based on this library. Thus, the terms and
-conditions of the GNU General Public License cover the whole
-combination.
-
-As a special exception, the copyright holders of this library give you
-permission to link this library with independent modules to produce an
-executable, regardless of the license terms of these independent
-modules, and to copy and distribute the resulting executable under
-terms of your choice, provided that you also meet, for each linked
-independent module, the terms and conditions of the license of that
-module. An independent module is a module which is not derived from
-or based on this library. If you modify this library, you may extend
-this exception to your version of the library, but you are not
-obligated to do so. If you do not wish to do so, delete this
-exception statement from your version. */
-
-
-package java.util;
-
-/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
- * "The Java Language Specification", ISBN 0-201-63451-1
- * plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
- * Status: Believed complete and correct
-
-/**
- * Stack provides a Last In First Out (LIFO) data type, commonly known
- * as a Stack. Stack itself extends Vector and provides the additional
- * methods for stack manipulation (push, pop, peek). You can also seek for
- * the 1-based position of an element on the stack.
- *
- * @author Warren Levy (warrenl@cygnus.com)
- * @author Eric Blake (ebb9@email.byu.edu)
- * @see List
- * @see AbstractList
- * @see LinkedList
- * @since 1.0
- * @status updated to 1.4
- */
-public class Stack/*<T>*/ extends Vector/*<T>*/
-{
- // We could use Vector methods internally for the following methods,
- // but have used Vector fields directly for efficiency (i.e. this
- // often reduces out duplicate bounds checking).
-
- /**
- * Compatible with JDK 1.0+.
- */
- private static final long serialVersionUID = 1224463164541339165L;
-
- /**
- * This constructor creates a new Stack, initially empty
- */
- public Stack()
- {
- }
-
- /**
- * Pushes an Object onto the top of the stack. This method is effectively
- * the same as addElement(item).
- *
- * @param item the Object to push onto the stack
- * @return the Object pushed onto the stack
- * @see Vector#addElement(Object)
- */
- public Object push(Object item)
- {
- // When growing the Stack, use the Vector routines in case more
- // memory is needed.
- // Note: spec indicates that this method *always* returns obj passed in!
-
- addElement(item);
- return item;
- }
-
- /**
- * Pops an item from the stack and returns it. The item popped is
- * removed from the Stack.
- *
- * @return the Object popped from the stack
- * @throws EmptyStackException if the stack is empty
- */
- //@SuppressWarnings("unchecked")
- public synchronized Object pop()
- {
- if (size == 0)
- throw new /*EmptyStack*/Exception("EmptyStackException");
-
- Object obj = array[--size];
-
- // Set topmost element to null to assist the gc in cleanup.
- array[size] = null;
- return obj;
- }
-
- /**
- * Returns the top Object on the stack without removing it.
- *
- * @return the top Object on the stack
- * @throws EmptyStackException if the stack is empty
- */
- //@SuppressWarnings("unchecked")
- public synchronized Object peek()
- {
- if (size == 0)
- throw new /*EmptyStack*/Exception("EmptyStackException");
-
- return array[size - 1];
- }
-
- /**
- * Tests if the stack is empty.
- *
- * @return true if the stack contains no items, false otherwise
- */
- public synchronized boolean empty()
- {
- return size == 0;
- }
-
- /**
- * Returns the position of an Object on the stack, with the top
- * most Object being at position 1, and each Object deeper in the
- * stack at depth + 1.
- *
- * @param o The object to search for
- * @return The 1 based depth of the Object, or -1 if the Object
- * is not on the stack
- */
- public synchronized int search(Object o)
- {
- int i = size;
- while (--i >= 0)
- if (o.equals(array[i]))
- return size - i;
- return -1;
- }
-}