package br.com.livro.rest;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
@Provider
@Produces(MediaType.APPLICATION_JSON + ";charset=utf-8")
@Consumes(MediaType.APPLICATION_JSON + ";charset=utf-8")
public final class GsonMessageBodyHandler implements MessageBodyWriter<Object>,
MessageBodyReader<Object> {
private static final String UTF_8 = "UTF-8";
private Gson gson;
private Gson getGson() {
if (gson == null) {
gson = new GsonBuilder().setPrettyPrinting().create();
}
return gson;
}
@Override
public boolean isReadable(Class<?> type, Type genericType,
java.lang.annotation.Annotation[] annotations, MediaType mediaType) {
return true;
}
@Override
public Object readFrom(Class<Object> type, Type genericType,
Annotation[] annotations, MediaType mediaType,
MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
throws IOException {
InputStreamReader streamReader = new InputStreamReader(entityStream,
UTF_8);
try {
Type jsonType;
if (type.equals(genericType)) {
jsonType = type;
} else {
jsonType = genericType;
}
return getGson().fromJson(streamReader, jsonType);
} finally {
streamReader.close();
}
}
@Override
public boolean isWriteable(Class<?> type, Type genericType,
Annotation[] annotations, MediaType mediaType) {
return true;
}
@Override
public long getSize(Object object, Class<?> type, Type genericType,
Annotation[] annotations, MediaType mediaType) {
return -1;
}
@Override
public void writeTo(Object object, Class<?> type, Type genericType,
Annotation[] annotations, MediaType mediaType,
MultivaluedMap<String, Object> httpHeaders,
OutputStream entityStream) throws IOException,
WebApplicationException {
OutputStreamWriter writer = new OutputStreamWriter(entityStream, UTF_8);
try {
Type jsonType;
if (type.equals(genericType)) {
jsonType = type;
} else {
jsonType = genericType;
}
getGson().toJson(object, jsonType, writer);
} finally {
writer.close();
}
}
}