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 com.alibaba.jstorm.hdfs.avro;
  
  import org.apache.avro.Schema;
  import org.apache.avro.SchemaNormalization;
  import org.apache.commons.codec.binary.Base64;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.security.NoSuchAlgorithmException;
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * A class to help (de)serialize a pre-defined set of Avro schemas.  Schemas should be listed, one per line, in a file
   * called "FixedAvroSerializer.config", which must be part of the Storm topology jar file.  Any schemas intended to be
   * used with this class **MUST** be defined in that file.
   */
  public class FixedAvroSerializer extends AbstractAvroSerializer {
  
      private final static String FP_ALGO = "CRC-64-AVRO";
      final Map<String, Schema> fingerprint2schemaMap = new HashMap<>();
      final Map<Schema, String> schema2fingerprintMap = new HashMap<>();
  
      public FixedAvroSerializer() throws IOException, NoSuchAlgorithmException {
          InputStream in = this.getClass().getClassLoader().getResourceAsStream("FixedAvroSerializer.config");
          BufferedReader reader = new BufferedReader(new InputStreamReader(in));
  
          String line;
          while((line = reader.readLine()) != null) {
              Schema schema = new Schema.Parser().parse(line);
              byte [] fp = SchemaNormalization.parsingFingerprint(FP_ALGO, schema);
              String fingerPrint = new String(Base64.decodeBase64(fp));
  
              fingerprint2schemaMap.put(fingerPrint, schema);
              schema2fingerprintMap.put(schema, fingerPrint);
          }
      }
  
      @Override
      public String getFingerprint(Schema schema) {
          return schema2fingerprintMap.get(schema);
      }
  
      @Override
      public Schema getSchema(String fingerPrint) {
          return fingerprint2schemaMap.get(fingerPrint);
      }
  }
  