wayang-platforms/wayang-flink/src/main/java/org/apache/wayang/flink/compiler/KeySelectorDistinct.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.wayang.flink.compiler;

import org.apache.flink.api.java.functions.KeySelector;

import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Base64;

/**
 * Wrapper for {@Link KeySelector}
 */
public class KeySelectorDistinct<T> implements KeySelector<T, String>, Serializable {

    public String getKey(T value){
        try {
            ByteArrayOutputStream b = new ByteArrayOutputStream();
            ObjectOutputStream objStream = new ObjectOutputStream(b);
            objStream.writeObject(value);
            return Base64.getEncoder().encodeToString(b.toByteArray());
        }finally {
            return "";
        }
    }

}