stem.java

thinking in java 经典书的习题答案 希望对大家有帮助啊

// reusing/Stem.java
// TIJ4 Chapter Reusing, Exercise 9, page 246
/* Create a class called Root that contains an instance of each of the classes
* (that you also create) named Component1, Component2 and Component3. Derive a 
* class Stem from Root that also contains an instance of each "component." All 
* classes should have default constructors that print a message about that class.
*/
 
import static org.greggordon.tools.Print.*;

class Component1 {
	Component1() { println("Component1()"); }
}

class Component2 {
	Component2() { println("Component2()"); }
}

class Component3 {
	Component3() { println("Component3()"); }
}

class Root { 
	Component1 c1root;
	Component2 c2root;
	Component3 c3root;
	Root() { println("Root()"); } 
}

class Stem extends Root { 
	Component1 c1stem;
	Component2 c2stem;
	Component3 c3stem;
	Stem() { println("Stem()"); } 
	public static void main(String[] args) {
		Stem s = new Stem();
	}
}