Flink 는 어떤 데이터 형식 을 지원 합 니까?

package org.apache.flink.api.java.tuple;
​
import java.io.Serializable;
import org.apache.flink.annotation.Public;
import org.apache.flink.types.NullFieldException;
​
@Public
public abstract class Tuple implements Serializable {
    private static final long serialVersionUID = 1L;
    public static final int MAX_ARITY = 25;
    private static final Class<?>[] CLASSES = new Class[]{Tuple0.class, Tuple1.class, Tuple2.class, Tuple3.class, Tuple4.class, Tuple5.class, Tuple6.class, Tuple7.class, Tuple8.class, Tuple9.class, Tuple10.class, Tuple11.class, Tuple12.class, Tuple13.class, Tuple14.class, Tuple15.class, Tuple16.class, Tuple17.class, Tuple18.class, Tuple19.class, Tuple20.class, Tuple21.class, Tuple22.class, Tuple23.class, Tuple24.class, Tuple25.class};
​
    public Tuple() {
    }
​
    public abstract <T> T getField(int var1);
​
    public <T> T getFieldNotNull(int pos) {
        T field = this.getField(pos);
        if (field != null) {
            return field;
        } else {
            throw new NullFieldException(pos);
        }
    }
​
    public abstract <T> void setField(T var1, int var2);
​
    public abstract int getArity();
​
    public abstract <T extends Tuple> T copy();
​
    public static Class<? extends Tuple> getTupleClass(int arity) {
        if (arity >= 0 && arity <= 25) {
            return CLASSES[arity];
        } else {
            throw new IllegalArgumentException("The tuple arity must be in [0, 25].");
        }
    }
​
    public static Tuple newInstance(int arity) {
        switch(arity) {
        case 0:
            return Tuple0.INSTANCE;
        case 1:
            return new Tuple1();
        case 2:
            return new Tuple2();
        case 3:
            return new Tuple3();
        case 4:
            return new Tuple4();
        case 5:
            return new Tuple5();
        case 6:
            return new Tuple6();
        case 7:
            return new Tuple7();
        case 8:
            return new Tuple8();
        case 9:
            return new Tuple9();
        case 10:
            return new Tuple10();
        case 11:
            return new Tuple11();
        case 12:
            return new Tuple12();
        case 13:
            return new Tuple13();
        case 14:
            return new Tuple14();
        case 15:
            return new Tuple15();
        case 16:
            return new Tuple16();
        case 17:
            return new Tuple17();
        case 18:
            return new Tuple18();
        case 19:
            return new Tuple19();
        case 20:
            return new Tuple20();
        case 21:
            return new Tuple21();
        case 22:
            return new Tuple22();
        case 23:
            return new Tuple23();
        case 24:
            return new Tuple24();
        case 25:
            return new Tuple25();
        default:
            throw new IllegalArgumentException("The tuple arity must be in [0, 25].");
        }
    }
}

ackage org.apache.flink.api.java.tuple;
​
import java.io.ObjectStreamException;
import org.apache.flink.annotation.Public;
​
@Public
public class Tuple0 extends Tuple {
    private static final long serialVersionUID = 1L;
    public static final Tuple0 INSTANCE = new Tuple0();
​
    public Tuple0() {
    }
​
    public int getArity() {
        return 0;
    }
​
    public <T> T getField(int pos) {
        throw new IndexOutOfBoundsException(String.valueOf(pos));
    }
​
    public <T> void setField(T value, int pos) {
        throw new IndexOutOfBoundsException(String.valueOf(pos));
    }
​
    public Tuple0 copy() {
        return new Tuple0();
    }
​
    public String toString() {
        return "()";
    }
​
    public boolean equals(Object o) {
        return this == o || o instanceof Tuple0;
    }
​
    public int hashCode() {
        return 0;
    }
​
    private Object readResolve() throws ObjectStreamException {
        return INSTANCE;
    }
}

Tuple tuple = Tuple.newInstance(1);

Tuple3<String, String, String> tuple3 = Tuple3.of("test0", "test1", "test2");
System.out.println(tuple3.f0); // test0
System.out.println(tuple3.f1); // test1
System.out.println(tuple3.f2); // test2

public class WordWithCount {
    public String word;
    public int count;
    public WordWithCount() {}
    public WordWithCount(String word, int count) { this.word = word; this.count = count; }
}
    DataStream<WordWithCount> wordCounts = env.fromElements(
    new WordWithCount("hello", 1),
    new WordWithCount("world", 2));
    wordCounts.keyBy("word");

List<String> l1 = new ArrayList<String>();
List<Integer> l2 = new ArrayList<Integer>();
System.out.println(l1.getClass() == l2.getClass());