Java chain classes

问题

I build a main class runs 5 classes, and make them able to pass string to each other. I just post main class + class 1 and 4.

Main class:

public class main {
public static void main(String[] args){

    class4 c4 = new class4(c1);

    class3 c3 = new class3(c4);

    class2 c2 = new class2(c3);
    c2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    c2.setSize(200,100);
    c2.setLocationRelativeTo(null);
    c2.setVisible(true);

    class1 c1 = new class1(c2);
    c1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    c1.setSize(200,100);
    c1.setLocationRelativeTo(null);
    c1.setVisible(true);


}

}

Class 1:

public class class1 extends JFrame{
private JButton jb;

private class2 c2;
public class1(class2 c2){
    this();
    this.c2 = c2;
    }


public class1(){
    super("");
    setLayout(new FlowLayout());

    jb = new JButton("click click");
    add(jb);

    jb.addActionListener(
            new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    sayHi("Hi buddy");
                }});
}
public void sayHi(String x){
    c2.recieveHi(x);
}

public void recieveHi(String x){
    System.out.println(x);
}

}

Class 5:

public class class4 {

private class1 c1;
public class4(class1 c1){
    //this();
    this.c1 = c1;
}
public void recieveHi(String x){
    System.out.println(x);
    killMessenger();
}
public void killMessenger(){
    String s = "back to class 1";
    c1.recieveHi(s);
}

}

Class 1 pass String to class2, which pass String to class 3 etc.. When class4 recieve String, i need to pass a String to class1.. As you can see in my main class, i need to bind them e.g

class 1 c1 = new class1(c2);

Doing it with class4 c4 = new class4(c1) doesn't work, because class1 isn't made yet. There will always be an lose end to it, so there might be a method to fix it.

回答1:

You could have a setter method, so you don't pass c1 in the constructor but after the class1 instance is created. In your class4 class

public void setClass1Object(class1 pC1) {
    this.c1 = pC1;
}

来源：https://stackoverflow.com/questions/21220273/java-chain-classes