/*
* Copyright (c) 2002, 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package org.jboss.com.sun.corba.se.spi.orbutil.fsm;
/**
*
* @author Ken Cavanaugh
*/
public interface Guard
{
public static final class Complement extends GuardBase
{
private Guard guard;
public Complement(GuardBase guard)
{
super("not(" + guard.getName() + ")");
this.guard = guard;
}
public Result evaluate(FSM fsm, Input in)
{
return guard.evaluate(fsm, in).complement();
}
}
public static final class Result
{
private String name;
private Result(String name)
{
this.name = name;
}
public static Result convert(boolean res)
{
return res ? ENABLED : DISABLED;
}
public Result complement()
{
if (this == ENABLED)
return DISABLED;
else if (this == DISABLED)
return ENABLED;
else
return DEFERED;
}
public String toString()
{
return "Guard.Result[" + name + "]";
}
public static final Result ENABLED = new Result("ENABLED");
public static final Result DISABLED = new Result("DISABLED");
public static final Result DEFERED = new Result("DEFERED");
}
/**
* Called by the state engine to determine whether a transition is enabled, defered, or disabled. The result is
* interpreted as follows:
* <ul>
* <li>ENABLED if the transition is ready to proceed
* <li>DISABLED if the transition is not ready to proceed
* <li>DEFERED if the action associated with the transition is to be deferred. This means that the input will not be
* acted upon, but rather it will be saved for later execution. Typically this is implemented using a CondVar wait,
* and the blocked thread represents the defered input. The defered input is retried when the thread runs again.
* </ul>
*
* @param FSM
* fsm is the state machine causing this action.
* @param Input
* in is the input that caused the transition.
*/
public Result evaluate(FSM fsm, Input in);
}
// end of Action.java