/*
    *    Copyright 2009-2021 the original author or authors.
    *
    *    Licensed 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.ibatis.cache.decorators;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.ObjectStreamClass;
  import java.io.Serializable;
  
  import org.apache.ibatis.cache.Cache;
  import org.apache.ibatis.cache.CacheException;
  import org.apache.ibatis.io.Resources;
  import org.apache.ibatis.io.SerialFilterChecker;
  
  /**
   * @author Clinton Begin
   */
  public class SerializedCache implements Cache {
  
    private final Cache delegate;
  
    public SerializedCache(Cache delegate) {
      this.delegate = delegate;
    }
  
    @Override
    public String getId() {
      return delegate.getId();
    }
  
    @Override
    public int getSize() {
      return delegate.getSize();
    }
  
    @Override
    public void putObject(Object key, Object object) {
      if (object == null || object instanceof Serializable) {
        delegate.putObject(key, serialize((Serializable) object));
      } else {
        throw new CacheException("SharedCache failed to make a copy of a non-serializable object: " + object);
      }
    }
  
    @Override
    public Object getObject(Object key) {
      Object object = delegate.getObject(key);
      return object == null ? null : deserialize((byte[]) object);
    }
  
    @Override
    public Object removeObject(Object key) {
      return delegate.removeObject(key);
    }
  
    @Override
    public void clear() {
      delegate.clear();
    }
  
    @Override
    public int hashCode() {
      return delegate.hashCode();
    }
  
    @Override
    public boolean equals(Object obj) {
      return delegate.equals(obj);
    }
  
    private byte[] serialize(Serializable value) {
      try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
          ObjectOutputStream oos = new ObjectOutputStream(bos)) {
        oos.writeObject(value);
        oos.flush();
        return bos.toByteArray();
      } catch (Exception e) {
        throw new CacheException("Error serializing object.  Cause: " + e, e);
      }
    }
  
    private Serializable deserialize(byte[] value) {
     SerialFilterChecker.check();
     Serializable result;
     try (ByteArrayInputStream bis = new ByteArrayInputStream(value);
         ObjectInputStream ois = new CustomObjectInputStream(bis)) {
       result = (Serializable) ois.readObject();
     } catch (Exception e) {
       throw new CacheException("Error deserializing object.  Cause: " + e, e);
     }
     return result;
   }
 
   public static class CustomObjectInputStream extends ObjectInputStream {
 
     public CustomObjectInputStream(InputStream in) throws IOException {
       super(in);
     }
 
     @Override
     protected Class<?> resolveClass(ObjectStreamClass desc) throws ClassNotFoundException {
       return Resources.classForName(desc.getName());
     }
 
   }
 
 }