package com.sdyc.ndmp.protobuf.serializer;

import com.google.protobuf.GeneratedMessage;

import java.lang.reflect.Method;

/**
 * <pre>
 *
 * Created by IntelliJ IDEA.
 * User: zhenqin
 * Date: 14-7-28
 * Time: 下午3:36
 * To change this template use File | Settings | File Templates.
 *
 * </pre>
 *
 * @author zhenqin
 */
public class ProtobufClassSerializer implements Serializer<GeneratedMessage> {

    /**
     * 字符编码
     */
    protected String charset = "UTF-8";




    protected final Class<? extends GeneratedMessage> objectClass;



    protected Method parseMethod;


    public ProtobufClassSerializer(Class<? extends GeneratedMessage> objectClass) {
        this(objectClass, "UTF-8");
    }


    public ProtobufClassSerializer(Class<? extends GeneratedMessage> objectClass, String charset) {
        this.charset = charset;
        this.objectClass = objectClass;
    }

    @Override
    public byte[] serialize(GeneratedMessage o) {
        if (o == null) {
            return null;
        }

        return o.toByteArray();
    }

    @Override
    public GeneratedMessage deserialize(byte[] bytes) {
        if (bytes == null || bytes.length == 0) {
            return null;
        }
        // 检查一下Netty Protobuf解码器是怎么写的
        try {
            if (parseMethod == null) {
                parseMethod = objectClass.getMethod("parseFrom", byte[].class);
            }
            return (GeneratedMessage) parseMethod.invoke(null, bytes);
        } catch (NoSuchMethodException e) {
            throw new IllegalStateException("class: " + objectClass.getName() + " has not method: parseFrom(byte[]).", e);
        } catch (Exception e) {
            throw new IllegalStateException("reflection error!", e);
        }
    }



    public String getCharset() {
        return charset;
    }

    public void setCharset(String charset) {
        this.charset = charset;
    }
}