/// <summary> Sets the next node in the queue, and returns it.</summary>
//@ requires next != this ;
//@ assignable m_Next;
//@ ensures m_Next==next && \result==next;
public virtual QueueXmlNode next(QueueXmlNode next)
{
return m_Next = next;
} //@ nowarn Invariant; // Because it stupidly checks the Queue invariant!
/// <summary> Appends an object to the back of the queue.
///
/// </summary>
/// <param name="Item">the object to be appended
/// </param>
/// <returns> the object appended
/// </returns>
//@ requires Item != null;
//@ assignable m_Head, m_Tail, m_Tail.m_Next, m_Head.m_Next, m_Size;
//@ ensures m_Head != null;
//@ ensures m_Tail != \old(m_Tail);
//@ ensures m_Size == \old(m_Size) + 1;
//@ ensures \old(m_Size) == 0 ==> m_Head == m_Tail;
//@ ensures \old(m_Size) != 0 ==> m_Head == \old(m_Head);
//@ ensures m_Tail.contents() == \old(Item);
//@ ensures \result == Item;
//UPGRADE_NOTE: Synchronized keyword was removed from method 'push'. Lock expression was added. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1027'"
public virtual System.Object push(System.Object Item)
{
lock (this)
{
QueueXmlNode newXmlNode = new QueueXmlNode(this, Item);
if (m_Head == null)
{
m_Head = m_Tail = newXmlNode;
}
else
{
m_Tail = m_Tail.next(newXmlNode);
}
m_Size++;
return Item;
}
}
/// <summary> Pops an object from the front of the queue.
///
/// </summary>
/// <returns> the object at the front of the queue
/// </returns>
/// <exception cref="RuntimeException">if the queue is empty
/// </exception>
//@ assignable m_Head, m_Tail, m_Size;
//@ ensures m_Size == \old(m_Size) - 1;
//@ ensures m_Head == \old(m_Head.m_Next);
//@ ensures m_Head != null ==> m_Tail == \old(m_Tail);
//@ ensures \result == \old(m_Head.m_Contents);
//@ signals (RuntimeException) \old(m_Head) == null;
//UPGRADE_NOTE: Synchronized keyword was removed from method 'pop'. Lock expression was added. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1027'"
public virtual System.Object pop()
{
lock (this)
{
if (m_Head == null)
{
throw new System.SystemException("Queue is empty");
}
System.Object retval = m_Head.contents();
m_Size--;
m_Head = m_Head.next();
// Here we need to either tell ESC/Java some facts about
// the contents of the list after popping off the head,
// or turn off the 'invariant' warnings.
//
//@ assume m_Size == 0 <==> m_Head == null;
//@ assume m_Size == 1 <==> m_Head == m_Tail;
if (m_Head == null)
{
m_Tail = null;
}
return retval;
}
}
//@ public invariant m_Head == null <==> m_Tail == null;
//@public invariant m_Tail != null ==> m_Tail.m_Next == null;
//@ public invariant m_Size >= 0;
//@ public invariant m_Size == 0 <==> m_Head == null;
//@ public invariant m_Size == 1 <==> m_Head != null && m_Head == m_Tail;
//@ public invariant m_Size > 1 ==> m_Head != m_Tail;
//@ public invariant m_Size > 1 <== m_Head != m_Tail;
/// <summary> Removes all objects from the queue m_Tail.m_Next.</summary>
//@ assignable m_Size, m_Head, m_Tail;
//@ ensures m_Size == 0;
//@ ensures m_Head == null;
//@ ensures m_Tail == null;
//UPGRADE_NOTE: Synchronized keyword was removed from method 'removeAllElements'. Lock expression was added. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1027'"
public void removeAllElements()
{
lock (this)
{
m_Size = 0;
m_Head = null;
m_Tail = null;
}
}
