//----------------------------------------------------------------------------
// Copyright (C) 2011 Ingrid Nunes
//
// 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 2.1 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
//
// To contact the authors:
// http://inf.ufrgs.br/prosoft/bdi4jade/
//
//----------------------------------------------------------------------------
package bdi4jade.plan.planbody;
import bdi4jade.goal.BeliefGoal;
import bdi4jade.plan.Plan.EndState;
/**
* This plan body aims to achieve a {@link BeliefGoal}. It verifies when the
* plan begins its execution if the goal is already achieved. If so, nothing is
* performed, otherwise the method {@link #execute()} is invoked, as a
* replacement of the {@link #action()} method.
*
* @author Ingrid Nunes
*
*/
public abstract class BeliefGoalPlanBody extends AbstractPlanBody {
private static final long serialVersionUID = -2512248999988800844L;
/**
* This final implementation of the action method verifies the belief goal
* that triggered this plan body execution is already achieved (
* {@link #isGoalAchieved()}). If not, it invokes the {@link #execute()}
* method;
*/
@Override
public final void action() {
if (!isGoalAchieved()) {
execute();
}
}
/**
* This method is a placeholder for subclasses that should implement the set
* of steps needed to achieve this plan body goal.
*/
protected abstract void execute();
/**
* This method is a placeholder for subclasses. It is invoked by the
* {@link #onStart()} method, after it performs some pre-processing.
*/
protected void init() {
}
/**
* Returns true if the goal of this plan body was achieved. If so, it sets
* the end state to successful, which cases this plan body to complete its
* execution.
*
* @return true if goal was achieved, false otherwise.
*/
protected boolean isGoalAchieved() {
BeliefGoal<?> goal = (BeliefGoal<?>) getGoal();
if (goal.isAchieved(getBeliefBase())) {
setEndState(EndState.SUCCESSFUL);
return true;
}
return false;
}
/**
* Verifies if the goal that triggered this plan body execution is a
* {@link BeliefGoal}. If not, it throws an {@link IllegalArgumentException}
* .
*/
@Override
public final void onStart() {
if (!(getGoal() instanceof BeliefGoal))
throw new IllegalArgumentException("BeliefGoal expected.");
init();
}
}