unsupported.java

Java编程思想这本书很好

//: c11:Unsupported.java
// Sometimes methods defined in the
// Collection interfaces don't work!
// {ThrowsException}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import java.util.*;

public class Unsupported {
  static List a = Arrays.asList(
    "one two three four five six seven eight".split(" "));
  static List a2 = a.subList(3, 6);
  public static void main(String[] args) {
    System.out.println(a);
    System.out.println(a2);
    System.out.println("a.contains(" + a.get(0) + ") = " +
      a.contains(a.get(0)));
    System.out.println("a.containsAll(a2) = " +
      a.containsAll(a2));
    System.out.println("a.isEmpty() = " + a.isEmpty());
    System.out.println("a.indexOf(" + a.get(5) + ") = " +
      a.indexOf(a.get(5)));
    // Traverse backwards:
    ListIterator lit = a.listIterator(a.size());
    while(lit.hasPrevious())
      System.out.print(lit.previous() + " ");
    System.out.println();
    // Set the elements to different values:
    for(int i = 0; i < a.size(); i++)
      a.set(i, "47");
    System.out.println(a);
    // Compiles, but won't run:
    lit.add("X"); // Unsupported operation
    a.clear(); // Unsupported
    a.add("eleven"); // Unsupported
    a.addAll(a2); // Unsupported
    a.retainAll(a2); // Unsupported
    a.remove(a.get(0)); // Unsupported
    a.removeAll(a2); // Unsupported
  }
} ///:~