多態性の導入：2つの配列リストを1つの配列リスト（Java）に置換する

Question

割り当てのために、多形性と継承を既存のプログラムに導入しようとしています。

私が現在抱えている問題は、2つの別々のリストを1つのリストに置き換えることです。私はJavaプログラミング（読んでいる：それでそれではない）にかなり新しいので、これはとにかく不明な場合は謝罪します。

public class TaxiCo 
{ 
    // The name of this company. 
    private String companyName; 
    // The name of the company's base. 
    private final String base;  
    // The fleet of taxis. 
    private ArrayList<Taxi> taxiFleet; 
    // The fleet of shuttles. 
    private ArrayList<Shuttle> shuttleFleet; 
    // The fleet of vehicles. 
    private int nextID; 
    // A list of available destinations for shuttles. 
    private ArrayList<String> destinations; 

私はArrayList<Vehicle>でArrayList<Shuttle> shuttleFleetとArrayList<Taxi> taxiFleetを交換する必要があります。私はもともとArrayList<Vehicle> vehicleFleetを追加すると

は私がaddVehicleと呼ばれる新しいメソッドを作るために必要と思ったが、（誰かが私は正しい道を下に向かっていたと考えて包み、私はそのメソッドのコードが含まれます）、当分の間、それに対して決定しました。

だから私は単純に次を追加しました：

フィールド：

private ArrayList<Vehicle> vehicleFleet;

コンストラクタ：

vehicleFleet = new ArrayList<Vehicle>();

は、以下の方法を変更した：

public void addTaxi(Vehicle vehicle) 
{ 
    Vehicle taxi = new Taxi(base, "Car #" + nextID); 
    vehicleFleet.add(taxi); 
    // Increment the ID for the next one. 
    nextID++; 
} 

... addShuttleと類似しています。

編集：私はコンパイルしようとしたとき しかし、このコードが強調表示されています：この問題を解決する方法についてnew Taxi(base, "Car #" + nextID);and I get this error message.

思考？あなたがそれがより良いコードを作成したり、Java言語をより良く理解したりするのに役立つと思うなら、私はすべての批判にも開放されています。ありがとう！

ここではTaxiCoクラスの残りのコードを参考にしています。

public TaxiCo(String name, String base) 
{ 
    companyName = name; 
    base = "base"; 
    taxiFleet = new ArrayList<Taxi>(); 
    shuttleFleet = new ArrayList<Shuttle>(); 
    nextID = 1; 
    destinations = new ArrayList<String>(); 
    fillDestinations(); 
} 

public void addTaxi(Vehicle vehicle) 
{ 
    Taxi taxi = new Taxi(base, "Car #" + nextID); 
    taxiFleet.add(taxi); 
    // Increment the ID for the next one. 
    nextID++; 
}  

public void addShuttle() 
{ 
    // Sanity warning: 
    // The following is a thoroughly contrived way to create a route! 

    // Create a random list of destinations for its route. 
    Collections.shuffle(destinations); 
    ArrayList<String> route = new ArrayList<String>(); 
    // The starting point is always the base. 
    route.add(base); 
    // Decide on an (arbitrary) length for all routes. 
    final int ROUTE_LENGTH = 3; 
    for(int i = 0; i < ROUTE_LENGTH; i++) { 
     route.add(destinations.get(i)); 
    } 

    Shuttle shuttle = new Shuttle("Shuttle #" + nextID, route); 
    shuttleFleet.add(shuttle); 
    // Increment the ID for the next one. 
    nextID++; 
} 


public Vehicle lookup(String id) 
{ 
    boolean found = false; 
    Vehicle vehicle = null; 
    Iterator<vehicle> it = vehicleFleet.iterator(); 
    while(!found && it.hasNext()) { 
     vehicle = it.next(); 
     if(id.equals(vehicle.getID())) { 
      found = true; 
     } 
     else{ 
      return null; 
     } 
    } 
} 

    public void showStatus() 
{ 
    System.out.println("Current status of the " + companyName + " fleet"); 
    for(Taxi taxi : taxiFleet) { 
     System.out.println(taxi.getStatus()); 
    } 
    for(Shuttle shuttle : shuttleFleet) { 
     System.out.println(shuttle.getStatus()); 
    } 
} 


private void fillDestinations() 
{ 
    destinations.add("Canterbury West"); 
    destinations.add("Canterbury East"); 
    destinations.add("The University"); 
    destinations.add("Whitstable"); 
    destinations.add("Herne Bay"); 
    destinations.add("Sainsbury's"); 
    destinations.add("Darwin"); 
} 

...そして、addVehicleの方法は先に話していました。

public void addVehicle(Vehicle vehicle) 
{ 
    Vehicle taxi = new Taxi(base, "Car #" + nextID); 
    //taxiFleet.add(taxi); 
    fleet.addVehicle(taxi); 
    //Increment the ID for the next one. but do we need two... 
    nextID++; 

    //Create a random list of destinations for its route. 
    Collections.shuffle(destinations); 
    ArrayList<String> route = new ArrayList<String>(); 
    //The starting point is always the base. 
    route.add(base); 
    //Decide on an arbitrary length for all routes. 
    final int ROUTE_LENGTH = 3; 
    for(int i = 0; i < ROUTE_LENGTH; i++) { 
     route.add(destinations.get(i)); 
    } 

    Vehicle shuttle = new Shuttle("Shuttle #" + nextID, route); 
    //shuttleFeet.add(shuttle); 
    fleet.addVehicle(shuttle); 
    nextID++; 
} 

EDIT：

Vehicleクラス：

public class Vehicle 
{ 
// A unique ID for taxi/shuttle. 
protected String id; 
//private String id; 
// The next destination of this taxi/shuttle. 
//private String destination; 
protected String destination; 
// The location of this taxi/shuttle. 
//private String location; 
protected String location; 
//The fleet of taxis and shuttles. 
//protected ArrayList<Vehicles> vehicles; 

/** 
* Constructor for objects of class Vehicle 
*/ 
public Vehicle(String destination, String base, String id) 
{ 
    // initialise instance variables. 
    //this(); 
    this.id = id; 
    //this.destination = destination; 
    location = base; 
    destination = null; 
} 

/** 
* Return the ID of the taxi/shuttle. 
* @return The ID of the taxi/shuttle. 
*/ 
public String getID() 
{ 
    //return this.id; 
    return id; 
} 

/** 
* Accessor method for the taxi/shuttle ID. 
*/ 
protected void setID(String id) 
{ 
    this.id = id; 
    //return id; 
} 

/** 
* Return the destination of the taxi/shuttle. 
* @return The destination of the taxi/shuttle. 
*/ 
public String getDestination() 
{ 
    return destination; 
} 

/** 
* Set the intended destination of the taxi/shuttle. 
* @param destination The intended destination. 
*/ 
public void setDestination(String destination) 
{ 
    this.destination = destination; 
} 

/** 
* Return the location of the taxi/shuttle. 
* @return The location of the taxi/shuttle. 
*/ 
public String getLocation() 
{ 
    return location; 
} 

/** 
* Set the intended location of the taxi/shuttle. 
* @parm location The intended location. 
*/ 
public void setLocation(String location) 
{ 
    this.location = location; 
} 

/** 
* Return the status of this taxi/shuttle. 
* @return The status. 

public String getStatus() 
{ 
    return id + " at " + location + " headed for " + 
      destination; 
} 
*/ 

タクシークラス：

public class Taxi extends Vehicle 
{ 
//Moved to the Vehicle SuperClass. 
//private String id; 
// The destination of this taxi. 
//private String destination; 
// The location of this taxi. 
//private String location; 
// Whether it is free or not. 
private boolean free; 

/** 
* Constructor for objects of class Taxi. 
* @param base The name of the company's base. 
* @param id This taxi's unique id. 
*/ 
public Taxi(String destination, String id, String base) 
{ 
    //this.id = id; 
    //super(); 
    super(destination, id, base); 
    //location = base; 
    //super(location); 
    //destination = null; 
    free = true; 
} 

/** 
* Book this taxi to the given destination. 
* The status of the taxi will no longer be free. 
* @param destination The taxi's destination. 
*/ 
public void book(String destination) 
{ 
    setDestination(destination); 
    free = false; 
} 

/** 
* Return the status of this taxi. 
* @return The status. 
*/ 
public String getStatus() 
{ 
    return id + " at " + location + " headed for " + 
      destination; 
} 


/** 
* Return the ID of the taxi. 
* @return The ID of the taxi. 

public String getID() 
{ 
    //return id; 
} 
*/ 

/** 
* Accessor method for the taxi/shuttle ID. 
*/ 
public void setID(String id) 
{ 
    super.setID(id); 
    //return id; 
} 

/** 
* Return the location of the taxi. 
* @return The location of the taxi. 

public String getLocation() 
{ 
    return location; 
} 
*/ 

/** 
* Return the destination of the taxi. 
* @return The destination of the taxi. 

public String getDestination() 
{ 
    return destination; 
} 
*/ 

/** 
* Set the intented destination of the taxi. 
* @param destination The intended destination. 
*/ 
public void setDestination(String destination) 
{ 
    super.setDestination(destination); 
    //return destination; 
} 

/** 
* Set the intented destination of the taxi. 
* @param destination The intended destination. 
*/ 
public void setLocation(String location) 
{ 
    super.setLocation(location); 
    //return location; 
} 

/** 
* Indicate that this taxi has arrived at its destination. 
* As a result, it will be free. 
*/ 
public void arrived() 
{ 
    location = destination; 
    destination = null; 
    free = true; 
} 
} 

シャトルクラス：

public class Shuttle extends Vehicle 
{ 
//Moved to the Vehicle SuperClass. 
//private String id; 
// The next destination of this shuttle on its 
// circular route. 
//private String destination; 
// The location of this shuttle. 
//private String location; 
// The circular route of this shuttle. 
private ArrayList<String> route; 
// The destination number in route that the shuttle is 
// currently headed for. 
private int destinationNumber; 

/** 
* Constructor for objects of class Shuttle 
* @param id This shuttle's unique id. 
* @param route The route taken by this shuttle. 
*    The first entry is the starting location. 
*/ 
public Shuttle(String destination, String id, String base, ArrayList<String> route) 
{ 
    //this.id = id; 
    super(id, destination, base); 
    setRoute(route); 
} 

/** 
* Return the status of this shuttle. 
* @return The status. 
*/ 
public String getStatus() 
{ 
    return id + " at " + location + " headed for " + 
      destination; 
} 


/** 
* Return the ID of the shuttle. 
* @return The ID of the shuttle. 

public String getID() 
{ 
    return id; 
} 
*/ 

/** 
* Accessor method for the taxi/shuttle ID. 
*/ 
public void setID(String id) 
{ 
    super.setID(id); 
    //return id; 
} 

/** 
* Return the location of the shuttle. 
* @return The location of the shuttle. 

public String getLocation() 
{ 
    return location; 
} 
*/ 

/** 
* Return the destination of the shuttle. 
* @return The destination of the shuttle. 

public String getDestination() 
{ 
    return destination; 
} 
*/ 

/** 
* Indicate that this shuttle has arrived at its next destination. 
*/ 
public void arrived() 
{ 
    location = destination; 
    setNextDestination(); 
} 

/** 
* Set the next destination of the shuttle. 
*/ 
private void setNextDestination() 
{ 
    destinationNumber++; 
    if(destinationNumber >= route.size()) { 
     // End of the circular route. 
     // Start from the beginning again. 
     destinationNumber = 0; 
    } 
    setDestination(route.get(destinationNumber)); 
} 

/** 
* Set the intented destination of the suttle. 
* @param destination The intended destination. 
*/ 
public void setDestination(String destination) 
{ 
    //this.destination = destination; 
    super.setDestination(destination); 
    //return destination; 
} 

/** 
* Set the intended location of the taxi/shuttle. 
* @parm location The intended location. 
*/ 
public void setLocation(String location) 
{ 
    this.location = location; 
} 

/** 
* Set the route for this shuttle. 
* @param route The circular list of destinations. 
*/ 
private void setRoute(ArrayList<String> route) 
{ 
    // Make a copy of the list parameter. 
    this.route = new ArrayList<String>(); 
    this.route.addAll(route); 
    destinationNumber = 0; 
    location = route.get(destinationNumber); 
    setNextDestination(); 
} 

ここで言及された他の3つのクラスがあります

}

Answer 1

このような簡単なことについての長い質問です。この行：エラーメッセージの状態として

new Vehicle(base, "Car #" + nextID) 

、あなたのVehicleコンストラクタの3つの文字列を必要とし、あなたはここでしか2を提供しています。それを次のように変更してください：

new Vehicle(base, "Car #" + nextID, "some string?"); 

これはうまくいきます。もちろん、最後のパラメータは何である必要があるかを確認してください。私はここには表示されません。そのコードは含まれていません。

Answer 2

なぜTaxiにある同じメソッドをVehicleに入れる必要がありますか？Vehicleによってアクセスできる継承のポイントではありませんか？あなたのコードは最後に動作しましたか？