如何擺脫類型轉換？

Question

我有一個胖接口：

public interface ISolver { 
    void solve(); 
    String printMsgs();  
    boolean hasSolution();  
    int getLeaderId();  
    void add(Agent agent);  
    void add(int item);  
    void add(String item);  
    void addAll(Agent[] data);  
    void addAll(int[] data);  
    void addAll(String[] data);  
    public void initiateStartState();  
    Agent next();  
    boolean hasNext();  
    public List<Integer> getLeftSenders();  
    public List<Integer> getRightSenders();  
    public List<Integer> getCurrentLeaders();  
    Agent get(int idx);  
} 

兩個類都繼承這個接口：

public class OneDirectSolver extends Solver{ 
    // some code.. 
} 

public class BiDirectSolver extends Solver{ 
    // some code.. 
} 

類BiDirectSolver使用在ISolver聲明的所有方法，但OneDirectSolver只使用一些方法。我想遵循界面分離原則。所以，我只留下了ISolver的常用方法。方法是特定於BiDirectSolver我在一個延伸ISolver

public interface ISolver { 
    void solve(); 
    String printMsgs(); 
    boolean hasSolution(); 
    int getLeaderId(); 
    void add(Agent agent); 
    void add(int item); 
    void add(String item); 
    void addAll(Agent[] data); 
    void addAll(int[] data); 
    void addAll(String[] data); 
    public void initiateStartState(); 
    Agent next(); 
    boolean hasNext(); 
} 

public interface BiDirectSolvable extends ISolver { 
    public List<Integer> getLeftSenders(); 
    public List<Integer> getRightSenders(); 
    public List<Integer> getCurrentLeaders(); 
    Agent get(int idx); 
} 

另一個接口移動但現在我有另一個問題。我試圖描述它。所以，我有2個客戶的BiDirectSolver，並且OneDirectSolver：

public class OneDirectPanel extends MyAbstractPanel { 

    private OneDirectSolvable solver; 

    public void setSolver(OneDirectSolver solver) { 
     this.solver = solver; 
    } 
    //some code.. 
} 

public class BiDirectPanel extends MyAbstractPanel { 

    private BiDirectSolvable solver; 

    public void setSolver(BiDirectSolvable solver) { 
     this.solver = solver; 
    } 
    // some code 
} 

，現在我想以表示我創造OneDirectPanel的情況下，我的主類的片段，BiDirectPanel和ISolver：

public class GUI { 
    private ISolver solver; 
    private MyAbstractPanel panelWithPicture; 
    // a lot of code.. 
    if (comboBoxForMode.getSelectedItem().equals("one direct")) { 
     solver = new OneDirectSolver(); 
     panelWithPicture = new OneDirectPanel(); 
     panelWithPicture.setSolver((OneDirectSolver)solver); 
    } else { 
     solver = new BiDirectSolver(); 
     panelWithPicture = new BiDirectPanel(); 
     panelWithPicture.setSolver((BiDirectSolvable)solver); 
    } 
} 

我看到只有一個解決方案：

if (comboBoxForMode.getSelectedItem().equals("one direct")) { 
    OneDirectSolver solver = new OneDirectSolver(); 
    panelWithPicture = new OneDirectPanel(); 
    panelWithPicture.setSolver(solver); 
} else { 
    BiDirectSolvable solver = new BiDirectSolver(); 
    panelWithPicture = new BiDirectPanel(); 
    panelWithPicture.setSolver(solver); 
} 

但它是不可能的我，因爲我必須做一些actioms與求解它被創建後。我必須在所有情況下做到這一點。所以，我在主要課上做。 因此，在主類中我必須聲明類型ISolver的引用。

UPD： 最重要的是，如果我做一些動作，在主類求解它必須在OneDirectPanel和BiDirectPanel求解影響。

Answer 1

既然你暫時需要更具體的運行時類型，你可以分配給this.solver算賬：

private ISolver solver; 
... 
if (comboBoxForMode.getSelectedItem() 
        .equals("one direct")) { 
       OneDirectSolver solver = new OneDirectSolver(); 
       panelWithPicture = new OneDirectPanel(); 
       panelWithPicture.setSolver(solver); 
       this.solver = solver; 
      } else { 
       BiDirectSolvable solver = new BiDirectSolver(); 
       panelWithPicture = new BiDirectPanel(); 
       panelWithPicture.setSolver(solver); 
       this.solver = solver; 
      } 

Answer 2

首先你可以把你的求解器實例作爲MyAbstractPanel的屬性。這樣你有一個基地求解器屬性。

public abstract class MyAbstractPanel { 

     private ISolver solver; 

     public void setSolver(ISolver solver) { 
     this.solver = solver; 
     } 

     public void someWork(){ 
     this.solver.someWork(); 
     } 
    // implement this in child class 
     public abstract void doSomeSpecificWork(); 

    } 

    //assign solver object 
    ISolver solver = new OneDirectSolver(); 

    public class BiDirectPanel extends MyAbstractPanel { 
     public void doSomeSpecificWork(){ 
      ((OneDirectSolver)solver).doSomeSpecificWork(); 
    } 
// some code 

}

因爲解算器面板的屬性，我認爲這是不是一個好的做法，以保持ISolver類型的全球化志願服務青年在你的主類。希望這可以幫助。