thinking in java －第11章持有对象－练习4 -补充(2012-08-25 20:15)

源码

package collection.test;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class MusicGenerator {
    private List<String> musicList = new ArrayList<String>();
    private Iterator<String> iterator;

    public MusicGenerator(List<String> list) {
        musicList.addAll(list);
        iterator = musicList.iterator();
    }
    public String next() {

        if (iterator.hasNext()) {
            return iterator.next();
        } else {
            iterator = musicList.iterator();
            return iterator.next();
        }
    }
}

 

工具类

package collection.test;

import java.util.Collection;
import java.util.Map;

public class FillCollection {
    public static Collection<String> fill(Collection<String> collection,
            String musicName) {
        collection.add(musicName);
        return collection;

    }

    public static Map<String, String> fill(Map<String, String> map,
            String musicName) {
        map.put("name" + "_" + musicName, musicName);
        return map;

    }
}

测试

package collection.test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class TestGeneratorMusic {
    private static List<String> arrayList = new ArrayList<String>();
    private static List<String> linkedList = new LinkedList<String>();
    private static Set<String> hashSet = new HashSet<String>();
    private static Set<String> linkedHashSet = new LinkedHashSet<String>();
    private static Map<String, String> map = new HashMap<String, String>();

    public static void main(String[] args) {

        MusicGenerator generator = new MusicGenerator(Arrays.asList("as long ",
                "baby", "say goodbye"));
        for (int i = 0; i < 10; i++) {
            FillCollection.fill(arrayList, generator.next());
            FillCollection.fill(linkedList, generator.next());
            FillCollection.fill(hashSet, generator.next());
            FillCollection.fill(linkedHashSet, generator.next());
            FillCollection.fill(map, generator.next());
        }
        System.out.println(arrayList);
        System.out.println(linkedList);
        System.out.println(hashSet);
        System.out.println(linkedHashSet);
        System.out.println(map);
    }
}