拥有另一个对象的对象

Question

目前我正在设计一个使用Java的大富翁游戏。

游戏中的每个玩家都可以拥有不同的属性。我遇到的问题是如何为每个玩家分配不同的属性对象。我有一个Player类和一个Properties类。组成是做这件事的最好方法吗？如果是这样，我该怎么做？

Answer 1

我想补充一个新的类PropertyManager中。

这使您可以轻松地在单个位置提供业务规则（良好的关注点分离），而不必在通过一堆玩家或属性对象进行潜水时，如果您选择合成。这将使玩家和/或财产类别在未来随着买卖业务规则而变得沉重。

public final class PropertyManager { 

    /** 
    * The PropertyManager instance, example usage: 
    * PropertyManager.INSTANCE.buyProperty(property, buyer); 
    * NB: Good candidate for dependency injection instead if you are doing this. 
    */ 
    public static final PropertyManager INSTANCE = new PropertyManager(); 

    private static final Map<Property, Player> propertyListing = new HashMap<Property, Player>(); 

    /** 
    * Buy a property from the banker, banker or property manager could maintain 
    * Collection of available properties 
    */ 
    public void buyProperty(Player buyer, Property property) { 
    if (propertyListing.containsKey(property)) { 
     throw new IllegalStateException("Unable to buy unless owner sells it"); 
    } 
    propertyListing.put(property, buyer); 
    } 

    /** 
    * Broker a transaction between two players for the sale of a property 
    */ 
    public void sellProperty(Player seller, Player buyer, Property property) { 
    if (!propertyListing.containsKey(property)) { 
     throw new IllegalStateException("Unable to sell Property which is not owned"); 
    } 
    Player owner = propertyListing.get(property); 
    if (!owner.equals(seller)) { 
     throw new IllegalStateException("Unable to sell property seller doesn't own"); 
    } 
    // TODO : Deduct/transfer monies (ensure sufficient value in buyer account etc) 
    propertyListing.put(property, buyer); 
    } 

    /** 
    * Retrieve a List of all of the Player's properties 
    */ 
    public List<Property> getProperties(Player owner) { 
    // TODO Either iterate through the propertyListing or use a second Map for player to List<Property>, NB: they should be guarded with a shared lock if you do this (threading). 
    } 

    /** 
    * Retrieve the owner of a Property or null if it is unowned 
    */ 
    @Nullable // javax annotation indiciates can be null 
    public Player getOwner(Property property) { 
    return propertyListing.get(property); 
    } 

    /** 
    * Hide the constructor as the only property manager should be INSTANCE 
    */ 
    private PropertyManager() { 
    // Prevent further instantiation 
    } 
} 

Answer 2

组成作品。只要玩家有一个属性对象，并且属性对象包含所有必要的数据，你应该没问题（假设你实现了必要的getter和setter方法）。

Answer 3

该属性可以拥有属于播放器的所有者属性。

你也可以在属性播放器上建立一个列表。

Answer 4

想想现实世界中的条件。

当您在玩Monopoly并购买房产时，您将房产卡添加到您的房产列表中。

因此，在这种情况下，您是将Property对象添加到属性列表的Player对象。

public class Player 
{ 
    private List<Property> properties; 
} 

Answer 5

您将需要组合和多态性。

假设玩家可以有多个属性，您将需要一个属性列表。如果属性的属性可能不同，则可以应用多态性和继承。您可能只会看到下面的继承，但是当您获取不同的属性并操作它们时，您将需要多态性。

在主：

public static void main(String args[]){ 
    Player player1 = new Player(); 

    BlackProperty blackProperty = new BlackProperty(); 
    BlueProperty blueProperty = new BlueProperty(); 

    player1.addProperty(blackProperty); 
    player1.addProperty(blueProperty); 
} 

所有域类：

public class Player{ 
    private List<Properties> propertyList; 

    // getters and setters 

    public void addProperty(Properties properties){ 
    if(this.propertyList == null){ 
     this.propertyList = new ArrayList<Properties>(); 
    } 

    this.propertyList.add(properties); 
    } 
} 

public class Properties{ 
    private int noOfFloor; 
    // getters and setters 
} 

public class BlackProperty extend Properties{ 
    private String noOfGate; 
    // getters and setters 
} 

public class BlueProperty extend Properties{ 
    private String noOfLawn; 
    // getters and setters 
}