Line data    Source code

       1             : // Copyright (C) 2018 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.server.cache.serialize;
      16             : 
      17             : import com.google.common.base.Converter;
      18             : 
      19             : /**
      20             :  * Interface for serializing/deserializing a type to/from a persistent cache.
      21             :  *
      22             :  * <p>Implementations are null-hostile and will throw exceptions from {@link #serialize} when passed
      23             :  * null values, unless otherwise specified.
      24             :  */
      25             : public interface CacheSerializer<T> {
      26             :   /**
      27             :    * Convert a serializer of one type to another type using a {@link Converter}.
      28             :    *
      29             :    * @param delegate underlying serializer.
      30             :    * @param converter converter between an arbitrary type {@code T} and {@code delegate}'s type.
      31             :    * @return serializer of type {@code T}.
      32             :    */
      33             :   static <T, D> CacheSerializer<T> convert(CacheSerializer<D> delegate, Converter<T, D> converter) {
      34           1 :     return new CacheSerializer<>() {
      35             :       @Override
      36             :       public byte[] serialize(T object) {
      37           1 :         return delegate.serialize(converter.convert(object));
      38             :       }
      39             : 
      40             :       @Override
      41             :       public T deserialize(byte[] in) {
      42           1 :         return converter.reverse().convert(delegate.deserialize(in));
      43             :       }
      44             :     };
      45             :   }
      46             : 
      47             :   /**
      48             :    * Serializes the object to a new byte array.
      49             :    *
      50             :    * @param object object to serialize.
      51             :    * @return serialized byte array representation.
      52             :    * @throws RuntimeException for malformed input, for example null or an otherwise unsupported
      53             :    *     value.
      54             :    */
      55             :   byte[] serialize(T object);
      56             : 
      57             :   /**
      58             :    * Deserializes a single object from the given byte array.
      59             :    *
      60             :    * @param in serialized byte array representation.
      61             :    * @throws RuntimeException for malformed input, for example null or an otherwise corrupt
      62             :    *     serialized representation.
      63             :    */
      64             :   T deserialize(byte[] in);
      65             : }