content: /*
   * 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 io.ray.streaming.state.serialization.impl;
  
  import com.google.common.hash.Hashing;
  import io.ray.streaming.state.StateException;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /** AbstractSerialization. Generate row key. */
  public abstract class AbstractSerialization {
  
    private static final Logger LOG = LoggerFactory.getLogger(AbstractSerialization.class);
  
    public String generateRowKeyPrefix(String key) {
      if (StringUtils.isNotEmpty(key)) {
        String md5 = Hashing.md5().hashUnencodedChars(key).toString();
        if ("".equals(md5)) {
          throw new StateException("Invalid value to md5:" + key);
        }
        return StringUtils.substring(md5, 0, 4) + ":" + key;
      } else {
        LOG.warn("key is empty");
        return key;
      }
    }
  }
  