collection1.java

经典java书籍《thinking in java（第三版）》的源码

//: c11:Collection1.java
// Things you can do with all Collections.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
import com.bruceeckel.simpletest.*;
import java.util.*;
import com.bruceeckel.util.*;

public class Collection1 {
  private static Test monitor = new Test();
  public static void main(String[] args) {
    Collection c = new ArrayList();
    Collections2.fill(c, Collections2.countries, 5);
    c.add("ten");
    c.add("eleven");
    System.out.println(c);
    // Make an array from the List:
    Object[] array = c.toArray();
    // Make a String array from the List:
    String[] str = (String[])c.toArray(new String[1]);
    // Find max and min elements; this means
    // different things depending on the way
    // the Comparable interface is implemented:
    System.out.println("Collections.max(c) = " +
      Collections.max(c));
    System.out.println("Collections.min(c) = " +
      Collections.min(c));
    // Add a Collection to another Collection
    Collection c2 = new ArrayList();
    Collections2.fill(c2, Collections2.countries, 5);
    c.addAll(c2);
    System.out.println(c);
    c.remove(CountryCapitals.pairs[0][0]);
    System.out.println(c);
    c.remove(CountryCapitals.pairs[1][0]);
    System.out.println(c);
    // Remove all components that are
    //  in the argument collection:
    c.removeAll(c2);
    System.out.println(c);
    c.addAll(c2);
    System.out.println(c);
    // Is an element in this Collection?
    String val = CountryCapitals.pairs[3][0];
    System.out.println("c.contains(" + val  + ") = "
      + c.contains(val));
    // Is a Collection in this Collection?
    System.out.println(
      "c.containsAll(c2) = " + c.containsAll(c2));
    Collection c3 = ((List)c).subList(3, 5);
    // Keep all the elements that are in both
    // c2 and c3 (an intersection of sets):
    c2.retainAll(c3);
    System.out.println(c);
    // Throw away all the elements
    // in c2 that also appear in c3:
    c2.removeAll(c3);
    System.out.println("c.isEmpty() = " +  c.isEmpty());
    c = new ArrayList();
    Collections2.fill(c, Collections2.countries, 5);
    System.out.println(c);
    c.clear(); // Remove all elements
    System.out.println("after c.clear():");
    System.out.println(c);
    monitor.expect(new String[] {
      "[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO, " +
        "ten, eleven]",
      "Collections.max(c) = ten",
      "Collections.min(c) = ALGERIA",
      "[ALGERIA, ANGOLA, BENIN, BOTSWANA, BURKINA FASO, " +
      "ten, eleven, BURUNDI, CAMEROON, CAPE VERDE, " +
      "CENTRAL AFRICAN REPUBLIC, CHAD]",
      "[ANGOLA, BENIN, BOTSWANA, BURKINA FASO, ten, " +
      "eleven, BURUNDI, CAMEROON, CAPE VERDE, " +
      "CENTRAL AFRICAN REPUBLIC, CHAD]",
      "[BENIN, BOTSWANA, BURKINA FASO, ten, eleven, " +
      "BURUNDI, CAMEROON, CAPE VERDE, " +
      "CENTRAL AFRICAN REPUBLIC, CHAD]",
      "[BENIN, BOTSWANA, BURKINA FASO, ten, eleven]",
      "[BENIN, BOTSWANA, BURKINA FASO, ten, eleven, " +
      "BURUNDI, CAMEROON, CAPE VERDE, " +
      "CENTRAL AFRICAN REPUBLIC, CHAD]",
      "c.contains(BOTSWANA) = true",
      "c.containsAll(c2) = true",
      "[BENIN, BOTSWANA, BURKINA FASO, ten, eleven, " +
      "BURUNDI, CAMEROON, CAPE VERDE, " +
      "CENTRAL AFRICAN REPUBLIC, CHAD]",
      "c.isEmpty() = false",
      "[COMOROS, CONGO, DJIBOUTI, EGYPT, " +
      "EQUATORIAL GUINEA]",
      "after c.clear():",
      "[]"
    });
  }
} ///:~