es.usc.citius.hipster.model.Transition Maven / Gradle / Ivy
/*
* Copyright 2014 CITIUS , University of Santiago de Compostela.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package es.usc.citius.hipster.model;
/**
* Defines a transition between states. When two states are connected
* a transition exists between them. An action may be specified
* to be part of a transition, which is needed in some kind of problems
* to evaluate their cost.
*
* When the problem does not involve actions, this class is used
* as follows: {@code Transition}
*
* @param type of the actions
* @param type of the state
*
* @author Pablo Rodríguez Mier <[email protected]>
* @author Adrián González Sieira <[email protected]>
*/
public class Transition {
// Source state (origin) of the transition
private S fromState;
// Action applied to fromState
private A action;
// Resultant state after applying the action to fromState
private S state;
/**
* Constructor for transitions which does not store information about
* the parent state.
*
* @param action action associated to this transition
* @param state to which this transition is addressed
*/
public Transition(A action, S state) {
this.action = action;
this.state = state;
}
/**
* Constructor for transitions that store the
* state from which the transition comes from.
*
* @param fromState state origin of the transition
* @param action action associated to this transition
* @param toState state destination of the transition
*
* @see {@link #create(Object, Object, Object)}
*/
public Transition(S fromState, A action, S toState) {
this.fromState = fromState;
this.action = action;
this.state = toState;
}
/**
* Instantiates a transition specifying an action, the origin and
* destination states.
*
* @param fromState state origin of the transition
* @param action action associated to this transition
* @param toState state destination of the transition
* @param type of the actions
* @param type of the state
* @return instance of a transition with an origin, destination and action
*/
public static Transition create(S fromState, A action, S toState){
return new Transition(fromState, action, toState);
}
/**
* Offers a way to instantiate a transition without specifying an action but
* only the origin and destination states.
*
* @param fromState state origin of the transition
* @param toState state destination of the transition
* @param type of the state
* @return instance of a transition with an origin and destination, but without an action
*/
public static Transition create(S fromState, S toState){
return new Transition(fromState, null, toState);
}
/**
* @return action associated to this transition
*/
public A getAction() {
return action;
}
/**
* @param action new action for this transition
*/
public void setAction(A action) {
this.action = action;
}
/**
* @return state which this transition is addressed
*/
public S getState() {
return state;
}
/**
* @param state new state destination of this transition
*/
public void setState(S state) {
this.state = state;
}
/**
* @return state origin of this transition
*/
public S getFromState() {
return fromState;
}
@Override
public String toString() {
return fromState + " ---(" + action + ")---> " + state;
}
}