Ybadoo - Soluções em Software Livre
Tutoriais
Programação Orientada a Objetos

Desenvolva um programa que simule o funcionamento de uma porta automática, utilizando o padrão State para representar o status da porta automática.

A porta automática pode assumir os seguintes estados:

closed: porta fechada

closing: porta fechando

open: porta aberta

opening: porta abrindo

stayOpen: manter aberta

As ações que a porta automática pode executar são:

click: botão para abrir/fechar a porta automática

complete: fim do processo de abertura/fechamento da porta automática

timeout: passagem de tempo num dado estado

A figura a seguir apresenta as transições entre os estados, com as suas respectivas ações.

Diagrama de estados

 

Arquivo DoorState.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * State
 *
 * Define uma interface para encapsulamento associado com um determinado estado do Context
 */
public abstract class DoorState
{
  /**
   * Referencia ao context
   */
  protected Door door;
  
  /**
   * Construtor padrao
   * 
   * @param door referencia ao context
   */
  public DoorState(Door door)
  {
    this.door = door;
  }

  /**
   * Click action
   */
  public abstract void click();

  /**
   * Complete action
   */
  public void complete()
  {
    
  }
  
  /**
   * Retornar o status da porta
   * 
   * @return status da porta
   */
  public abstract String status();

  /**
   * Timeout action
   */
  public void timeout()
  {
    
  }
}

Arquivo DoorClosed.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * ConcreteState
 *
 * Implementa um comportamento associado com um estado do Context
 */
public class DoorClosed extends DoorState
{
  /**
   * Construtor padrao
   * 
   * @param door referecia ao context
   */
  public DoorClosed(Door door)
  {
    super(door);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#click()
   */
  public void click()
  {
    this.door.setState(this.door.OPENING);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#status()
   */
  public String status()
  {
    return "CLOSED";
  }
}

Arquivo DoorClosing.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * ConcreteState
 *
 * Implementa um comportamento associado com um estado do Context
 */
public class DoorClosing extends DoorState
{
  /**
   * Construtor padrao
   * 
   * @param door referencia ao context
   */
  public DoorClosing(Door door)
  {
    super(door);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#click()
   */
  public void click()
  {
    this.door.setState(this.door.OPENING);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#complete()
   */
  public void complete()
  {
    this.door.setState(this.door.CLOSED);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#status()
   */
  public String status()
  {
    return "CLOSING";
  }
}

Arquivo DoorOpen.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * ConcreteState
 *
 * Implementa um comportamento associado com um estado do Context
 */
public class DoorOpen extends DoorState
{
  /**
   * Construtor padrao
   * 
   * @param door referencia ao context
   */
  public DoorOpen(Door door)
  {
    super(door);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#click()
   */
  public void click()
  {
    this.door.setState(this.door.STAYOPEN);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#timeout()
   */
  public void timeout()
  {
    this.door.setState(this.door.CLOSING);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#status()
   */
  public String status()
  {
    return "OPEN";
  }
}

Arquivo DoorOpening.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * ConcreteState
 *
 * Implementa um comportamento associado com um estado do Context
 */
public class DoorOpening extends DoorState
{
  /**
   * Construtor padrao
   * 
   * @param door referencia ao context
   */
  public DoorOpening(Door door)
  {
    super(door);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#click()
   */
  public void click()
  {
    this.door.setState(this.door.CLOSING);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#complete()
   */
  public void complete()
  {
    this.door.setState(this.door.OPEN);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#status()
   */
  public String status()
  {
    return "OPENING";
  }
}

Arquivo DoorStayOpen.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * ConcreteState
 *
 * Implementa um comportamento associado com um estado do Context
 */
public class DoorStayOpen extends DoorState
{
  /**
   * Construtor padrao
   * 
   * @param door referencia ao context
   */
  public DoorStayOpen(Door door)
  {
    super(door);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#click()
   */
  public void click()
  {
    this.door.setState(this.door.CLOSING);
  }
  
  /* (non-Javadoc)
   * @see com.ybadoo.DoorState#status()
   */
  public String status()
  {
    return "STAYOPEN";
  }
}

Arquivo Door.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * Context
 * 
 * Define a interface de interesse para os clientes
 * Mantem uma instancia de uma subclasse ConcreteState que define o estado corrente
 */
public class Door
{
  /**
   * ConcreteState
   */
  public final DoorState CLOSED = new DoorClosed(this);
  
  /**
   * ConcreteState
   */
  public final DoorState CLOSING = new DoorClosing(this);
  
  /**
   * ConcreteState
   */
  public final DoorState OPEN = new DoorOpen(this);
  
  /**
   * ConcreteState
   */
  public final DoorState OPENING = new DoorOpening(this);
  
  /**
   * ConcreteState
   */
  public final DoorState STAYOPEN = new DoorStayOpen(this);
  
  /**
   * Estado corrente
   */
  private DoorState state = CLOSED;

  /**
   * Click action
   */
  public void click()
  {
    this.state.click();  
  }

  /**
   * Complete action
   */
  public void complete()
  {
    this.state.complete();
  }
  
  /**
   * Alterar o status da porta
   * 
   * @param state status da porta
   */
  protected void setState(DoorState state)
  {
    this.state = state;
  }
  
  /**
   * Retornar o status da porta
   * 
   * @return status da porta
   */
  public String status()
  {
    return this.state.status();
  }

  /**
   * Timeout action
   */
  public void timeout()
  {
    this.state.timeout();
  }
}

Arquivo Application.java

/**
 * Copyright (C) 2009/2018 - Cristiano Lehrer (cristiano@ybadoo.com.br)
 *                  Ybadoo - Solucoes em Software Livre (www.ybadoo.com.br)
 *
 * Permission is granted to copy, distribute and/or modify this document
 * under the terms of the GNU Free Documentation License, Version 1.3
 * or any later version published by the Free Software Foundation; with
 * no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
 * A copy of the license is included in the section entitled "GNU
 * Free Documentation License".
 */

package com.ybadoo.tutoriais.poo;

/**
 * Classe de teste da aplicacao
 */
public class Application
{
  /**
   * Metodo principal da linguagem de programacao Java
   * 
   * @param args argumentos da linha de comando (nao utilizado)
   */
  public static void main(String[] args)
  {
    Door door = new Door();
    System.out.println(door.status());
    
    door.click();
    System.out.println(door.status());
    
    door.complete();
    System.out.println(door.status());
    
    door.timeout();
    System.out.println(door.status());
    
    door.click();
    System.out.println(door.status());
  }
}