/*
* JBoss, Home of Professional Open Source
* Copyright 2006, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags.
* See the copyright.txt in the distribution for a full listing
* of individual contributors.
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License, v. 2.1.
* This program is distributed in the hope that it will be useful, but WITHOUT A
* 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,
* v.2.1 along with this distribution; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
* (C) 2005-2006,
* @author JBoss Inc.
*/
/*
* Copyright (C) 2002,
*
* Arjuna Technologies Limited,
* Newcastle upon Tyne,
* Tyne and Wear,
* UK.
*
* $Id: ActivityHierarchy.java,v 1.1 2002/11/25 10:51:41 nmcl Exp $
*/
package com.arjuna.mw.wsas.activity;
/**
* This class represents a handle on a stack of activities.
* It should only be used for suspending and resuming the
* thread-to-activity association.
*
* The activity at the top of the stack is the current activity.
*
* @author Mark Little (mark.little@arjuna.com)
* @version $Id: ActivityHierarchy.java,v 1.1 2002/11/25 10:51:41 nmcl Exp $
* @since 1.0.
*/
public interface ActivityHierarchy
{
/**
* @return the number of activities associated with this stack.
*/
public int size ();
/**
* @return whether or not this is a valid context. If a single entry in
* the context is invalid then we assume the entire context is.
*/
public boolean valid ();
/**
* @param index index of the specific activity in the stack.
* @exception IndexOutOfBoundsException Thrown if the activity number
* is too large or small.
* @return the activity handle.
*/
public ActivityHandle activity (int index) throws IndexOutOfBoundsException;
/**
* @return the current activity in the context.
*/
public ActivityHandle current ();
/**
* Obtain a copy of this context. Although the context may be shared
* between different threads, the same instance of the context should
* not be.
*
* @return the context copy.
*/
public ActivityHierarchy copy ();
/**
* Overrides Object.equals
*
* Two contexts are equal if both hierarchies are identical.
*
* @return <code>true</code> if the two objects are the same,
* <code>false</code> otherwise.
*/
public boolean equals (Object obj);
/**
* Although users won't typically care what the underlying implementation
* of a context is, they will need to do comparisons.
* So, although this method is provided by Java.Object we have it here
* to ensure that we don't forget to implement it!
*
* @return the hash value for the target.
*/
public int hashCode ();
}