set2.java

中文JAVA编程思想第二版,一本很好的JAVA入门书籍!

//: c09:Set2.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// Putting your own type in a Set.
import java.util.*;

class MyType implements Comparable {
  private int i;
  public MyType(int n) { i = n; }
  public boolean equals(Object o) {
    return 
      (o instanceof MyType) 
      && (i == ((MyType)o).i);
  }
  public int hashCode() { return i; }
  public String toString() { return i + " "; }
  public int compareTo(Object o) {
    int i2 = ((MyType)o).i;
    return (i2 < i ? -1 : (i2 == i ? 0 : 1));
  }
}

public class Set2 {
  public static Set fill(Set a, int size) {
    for(int i = 0; i < size; i++)
      a.add(new MyType(i));
    return a;
  }
  public static void test(Set a) {
    fill(a, 10);
    fill(a, 10); // Try to add duplicates
    fill(a, 10);
    a.addAll(fill(new TreeSet(), 10));
    System.out.println(a);
  }
  public static void main(String[] args) {
    test(new HashSet());
    test(new TreeSet());
  }
} ///:~