GensonMessageConverter.java

package com.owlike.genson.ext.spring;

import java.io.IOException;
import java.lang.reflect.Type;
import java.nio.charset.Charset;
import java.util.Arrays;

import com.owlike.genson.*;
import org.springframework.core.MethodParameter;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;

import com.owlike.genson.annotation.WithBeanView;
import com.owlike.genson.stream.ObjectWriter;

public class GensonMessageConverter extends AbstractHttpMessageConverter<Object> {

  private final Genson genson;

  public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");

  public GensonMessageConverter() {
    this(new GensonBuilder().setHtmlSafe(true).setSkipNull(true).useBeanViews(true).create());
  }

  public GensonMessageConverter(Genson genson) {
    super(new MediaType("application", "json", DEFAULT_CHARSET));
    this.genson = genson;
  }

  @Override
  protected Object readInternal(Class<?> clazz, HttpInputMessage inputMessage)
    throws IOException, HttpMessageNotReadableException {
    MethodParameter mp = ThreadLocalHolder.get("__GENSON$method_param", MethodParameter.class);

    WithBeanView ann = null;
    Type type = clazz;
    if (mp != null) {
      ann = mp.getMethodAnnotation(WithBeanView.class);
      type = mp.getGenericParameterType();
    }

    GenericType<?> genericType = GenericType.of(type);

    if (ann != null)
      return genson.deserialize(genericType,
        genson.createReader(inputMessage.getBody()),
        new Context(genson, Arrays.asList(ann.views())));
    else
      return genson.deserialize(genericType, genson.createReader(inputMessage.getBody()), new Context(genson));
  }

  @Override
  protected boolean supports(Class<?> clazz) {
    return true;
  }

  @SuppressWarnings("unchecked")
  @Override
  protected void writeInternal(Object t, HttpOutputMessage outputMessage) throws IOException,
    HttpMessageNotWritableException {
    ObjectWriter writer = genson.createWriter(outputMessage.getBody());
    MethodParameter mp = ThreadLocalHolder.get("__GENSON$return_param", MethodParameter.class);
    WithBeanView ann = mp != null ? mp.getMethodAnnotation(WithBeanView.class) : null;
    if (ann != null)
      genson.serialize(t, writer, new Context(genson, Arrays.asList(ann.views())));
    else
      genson.serialize(t, writer, new Context(genson));
    writer.flush();
  }
}