Java8CollectClient.java

package trial.yy.java8.client.stream;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;

/**
 * Java8 java.util.stream.Stream#collect を試すためのサンプル
 * User: yy
 * Date: 13/04/17
 * Time: 22:23
 */
public class Java8CollectClient {

    public static void main(String[] args) {

        // 操作対象の文字列を格納したList
        List<String> srclist = Arrays.asList("defg", "defg", "x", "xyz", "zzzzzzzz", "abc", "abcde");

        // Collectors#toListを使用
        List<String> destList1 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.<String>toList());

        // Collectors#toCollection(ArrayList)を使用
        List<String> destList2 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.toCollection(ArrayList::new));

        // Collectors#toCollection(LinkedList)を使用
        List<String> destList3 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.toCollection(LinkedList::new));

        // Collectors#toSetを使用
        Set<String> destSet1 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.<String>toSet());

        // Collectors#toCollection(HashSet)を使用
        Set<String> destSet2 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.toCollection(HashSet::new));

        // Collectors#toCollection(TreeSet)を使用
        Set<String> destSet3 = srclist.stream().filter(e -> e.length() > 3).collect(Collectors.toCollection(TreeSet::new));

        // 結果(新しいCollection)の内容をまとめて出力
        System.out.println("destList1: " + destList1);
        System.out.println("destList2: " + destList2);
        System.out.println("destList3: " + destList3);

        System.out.println("destSet1: " + destSet1);
        System.out.println("destSet2: " + destSet2);
        System.out.println("destSet3: " + destSet3);
    }
}