ex3(3).java

JAVA编程思想第四版英文原版习题答案. pdf原版的

// containers/Ex3.java
// TIJ4 Chapter Containers, Exercise 3, page 809
/* Using Countries, fill a Set multiple times with the same data 
* and verify that the Set ends up with only one of each instance.
* Try this with HashSet, LinkedHashSet, and TreeSet.
*/
import java.util.*;
import java.util.regex.*;
import net.mindview.util.*;
import static org.greggordon.tools.Print.*;

public class Ex3 {
	public static void main(String[] args) {
		Set<String> hs = new HashSet<String>();
		Set<String> lhs = new LinkedHashSet<String>();
		Set<String> ts = new TreeSet<String>();
		println("HashSet hs = " + hs);
		println("LinkedHashSet lhs = " + lhs);
		println("TreeSet ts = " + ts);
		Map<String,String> hm = new HashMap<String,String>(0);
		Pattern p = Pattern.compile("Z[a-zA-Z]*");
		for(int i = 0; i < Countries.DATA.length; i++) {
			if(p.matcher(Countries.DATA[i][0]).matches())
			hm.put(Countries.DATA[i][0], Countries.DATA[i][0]);
		}
		println("hm.keySet() = " + hm.keySet());
		println("Adding hm.keySet()");
		hs.addAll(hm.keySet());
		lhs.addAll(hm.keySet());
		ts.addAll(hm.keySet());
		println("hs: " + hs);
		println("lhs: " + lhs);
		println("ts: " + ts);
		println("Adding 10 more times");
		for(int i = 0; i < 10; i++) {
			hs.addAll(hm.keySet());
			lhs.addAll(hm.keySet());
			ts.addAll(hm.keySet());
		}
		println("hs: " + hs);
		println("lhs: " + lhs);
		println("ts: " + ts);				
	}
}