WireConverter.java

// Copyright 2013 Square, Inc.
package retrofit.converter;

import com.squareup.wire.Message;
import com.squareup.wire.Wire;
import retrofit.mime.TypedByteArray;
import retrofit.mime.TypedInput;
import retrofit.mime.TypedOutput;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Type;

/**
 * A {@link Converter} that reads and writes protocol buffers using Wire.
 */
public class WireConverter implements Converter
{
  private static final String MIME_TYPE = "application/x-protobuf";

  private final Wire wire;

  /**
   * Create a converter with a default {@link Wire} instance.
   */
  public WireConverter()
  {
    this(new Wire());
  }

  /**
   * Create a converter using the supplied {@link Wire} instance.
   */
  public WireConverter(Wire wire)
  {
    this.wire = wire;
  }

  @SuppressWarnings("unchecked") //
  @Override
  public Object fromBody(TypedInput body, Type type) throws ConversionException
  {
    if (!(type instanceof Class<?>))
    {
      throw new IllegalArgumentException("Expected a raw Class<?> but was " + type);
    }
    Class<?> c = (Class<?>) type;
    if (!Message.class.isAssignableFrom(c))
    {
      throw new IllegalArgumentException("Expected a proto message but was " + c.getName());
    }

    if (!MIME_TYPE.equalsIgnoreCase(body.mimeType()))
    {
      throw new IllegalArgumentException("Expected a proto but was: " + body.mimeType());
    }

    InputStream in = null;
    try
    {
      in = body.in();
      return wire.parseFrom(in, (Class<Message>) c);
    }
    catch (IOException e)
    {
      throw new ConversionException(e);
    }
    finally
    {
      if (in != null)
      {
        try
        {
          in.close();
        }
        catch (IOException ignored)
        {
        }
      }
    }
  }

  @Override
  public TypedOutput toBody(Object object)
  {
    if (!(object instanceof Message))
    {
      throw new IllegalArgumentException(
          "Expected a proto message but was " + (object != null ? object.getClass().getName()
                                                                : "null"));
    }
    byte[] bytes = ((Message) object).toByteArray();
    return new TypedByteArray(MIME_TYPE, bytes);
  }
}