mixins37.java

JAVA编程思想第四版英文原版习题答案. pdf原版的

// generics/Mixins37.java
// TIJ3 Chapter Generics, Exercise 37, page 717
// Add a new mixin class Colored to Mixins.java, mix it into Mixin and
// show that it works.
import java.util.*;

interface TimeStamped { long getStamp(); } 

class TimeStampedImp implements TimeStamped {
	private final long timeStamp;
	public TimeStampedImp() {
		timeStamp = new Date().getTime();
	}
	public long getStamp() { return timeStamp; }
}

interface SerialNumbered { long getSerialNumber(); }

class SerialNumberedImp implements SerialNumbered {
	private static long counter = 1;
	private final long serialNumber = counter++;
	public long getSerialNumber() { return serialNumber; }
}


interface Color { String getColor();  }

class Colored implements Color {
	private String color = "blue";
	public void setColor(String col) { color = col; }
	public String getColor() { return color; }
}

interface Basic {
	public void set(String val);
	public String get();
}

class BasicImp implements Basic {
	private String value;
	public void set(String val) { value = val; }
	public String get() { return value; }
}

class Mixin extends BasicImp 
implements TimeStamped, SerialNumbered, Color {
	private TimeStamped timeStamp = new TimeStampedImp();
	private SerialNumbered serialNumber = new SerialNumberedImp();
	private Colored color = new Colored();
	public long getStamp() { return timeStamp.getStamp(); }
	public long getSerialNumber() { 
		return serialNumber.getSerialNumber(); 
	}
	public String getColor() { return color.getColor(); }
}


public class Mixins37 {
	public static void main(String[] args) {
		Mixin mixin1 = new Mixin(), mixin2 = new Mixin();
		mixin1.set("test string 1");
		mixin2.set("test string 2");
		System.out.println(mixin1.get() + " " + mixin1.getStamp() 
			+ " " + mixin1.getSerialNumber() + " " + 
			mixin1.getColor());
		System.out.println(mixin2.get() + " " + mixin2.getStamp() 
			+ " " + mixin2.getSerialNumber() + " " + 
			mixin2.getColor());
	}
}