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Modified version of HTTPClient used by The Grinder. The original
can be found at http://www.innovation.ch/java/HTTPClient/.
/*
* @(#)LinkedList.java 0.3-3 06/05/2001
*
* This file is part of the HTTPClient package
* Copyright (C) 1996-2001 Ronald Tschalär
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307, USA
*
* For questions, suggestions, bug-reports, enhancement-requests etc.
* I may be contacted at:
*
* [email protected]
*
* The HTTPClient's home page is located at:
*
* http://www.innovation.ch/java/HTTPClient/
*
*/
package HTTPClient;
/**
* This class implements a singly linked list.
*
* @version 0.3-3 06/05/2001
* @author Ronald Tschalär
*/
class LinkedList
{
/** head of list */
private LinkElement head = null;
/** tail of list (for faster adding) */
private LinkElement tail = null;
/**
* Add the specified element to the head of the list.
*
* @param elem the object to add to the list.
*/
public synchronized void addToHead(Object elem)
{
head = new LinkElement(elem, head);
if (head.next == null)
tail = head;
}
/**
* Add the specified element to the end of the list.
*
* @param elem the object to add to the list.
*/
public synchronized void addToEnd(Object elem)
{
if (head == null)
head = tail = new LinkElement(elem, null);
else
tail = (tail.next = new LinkElement(elem, null));
}
/**
* Remove the specified element from the list. Does nothing if the element
* is not in the list.
*
* @param elem the object to remove from the list.
*/
public synchronized void remove(Object elem)
{
if (head == null) return;
if (head.element == elem)
{
head = head.next;
return;
}
LinkElement curr = head;
while (curr.next != null)
{
if (curr.next.element == elem)
{
if (curr.next == tail) tail = curr;
curr.next = curr.next.next;
return;
}
curr = curr.next;
}
}
/**
* Return the first element in the list. The list is not modified in any
* way.
*
* @return the first element
*/
public synchronized Object getFirst()
{
if (head == null) return null;
return head.element;
}
private LinkElement next_enum = null;
/**
* Starts an enumeration of all the elements in this list. Note that only
* one enumeration can be active at any time.
*
* @return the first element, or null if the list is empty
*/
public synchronized Object enumerate()
{
if (head == null) return null;
next_enum = head.next;
return head.element;
}
/**
* Gets the next element in the enumeration. The enumeration must have
* been first initalized with a call to enumerate().
*
* @return the next element, or null if none left
* @see #enumerate()
*/
public synchronized Object next()
{
if (next_enum == null) return null;
Object elem = next_enum.element;
next_enum = next_enum.next;
return elem;
}
public static void main(String args[]) throws Exception
{
// LinkedList Test Suite
System.err.println("\n*** Linked List Tests ...");
LinkedList list = new LinkedList();
list.addToHead("One");
list.addToEnd("Last");
if (!list.getFirst().equals("One"))
throw new Exception("First element wrong");
if (!list.enumerate().equals("One"))
throw new Exception("First element wrong");
if (!list.next().equals("Last"))
throw new Exception("Last element wrong");
if (list.next() != null)
throw new Exception("End of list wrong");
list.remove("One");
if (!list.getFirst().equals("Last"))
throw new Exception("First element wrong");
list.remove("Last");
if (list.getFirst() != null)
throw new Exception("End of list wrong");
list = new LinkedList();
list.addToEnd("Last");
list.addToHead("One");
if (!list.getFirst().equals("One"))
throw new Exception("First element wrong");
if (!list.enumerate().equals("One"))
throw new Exception("First element wrong");
if (!list.next().equals("Last"))
throw new Exception("Last element wrong");
if (list.next() != null)
throw new Exception("End of list wrong");
if (!list.enumerate().equals("One"))
throw new Exception("First element wrong");
list.remove("One");
if (!list.next().equals("Last"))
throw new Exception("Last element wrong");
list.remove("Last");
if (list.next() != null)
throw new Exception("End of list wrong");
list = new LinkedList();
list.addToEnd("Last");
list.addToHead("Two");
list.addToHead("One");
if (!list.getFirst().equals("One"))
throw new Exception("First element wrong");
if (!list.enumerate().equals("One"))
throw new Exception("First element wrong");
if (!list.next().equals("Two"))
throw new Exception("Second element wrong");
if (!list.next().equals("Last"))
throw new Exception("Last element wrong");
if (list.next() != null)
throw new Exception("End of list wrong");
list.remove("Last");
list.remove("Two");
list.remove("One");
if (list.getFirst() != null)
throw new Exception("Empty list wrong");
System.err.println("\n*** Tests finished successfuly");
}
}
/**
* The represents a single element in the linked list.
*/
class LinkElement
{
Object element;
LinkElement next;
LinkElement(Object elem, LinkElement next)
{
this.element = elem;
this.next = next;
}
}