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
   *
   *   https://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.avro.message;
  
  import org.apache.avro.Schema;
  import org.apache.avro.SchemaNormalization;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * Interface for classes that can provide avro schemas by fingerprint.
   */
  public interface SchemaStore {
  
    /**
     * Retrieves a fingerprint by its AVRO-CRC-64 fingerprint.
     * 
     * @param fingerprint an AVRO-CRC-64 fingerprint long
     * @return a Schema with the given fingerprint, or null
     */
    Schema findByFingerprint(long fingerprint);
  
    /**
     * A map-based cache of schemas by AVRO-CRC-64 fingerprint.
     * <p>
     * This class is thread-safe.
     */
    class Cache implements SchemaStore {
      private final Map<Long, Schema> schemas = new ConcurrentHashMap<>();
  
      /**
       * Adds a schema to this cache that can be retrieved using its AVRO-CRC-64
       * fingerprint.
       *
       * @param schema a {@link Schema}
       */
      public void addSchema(Schema schema) {
        long fp = SchemaNormalization.parsingFingerprint64(schema);
        schemas.put(fp, schema);
      }
  
      @Override
      public Schema findByFingerprint(long fingerprint) {
        return schemas.get(fingerprint);
      }
    }
  }
  