package br.com.caelum.vraptor.deserialization.gson;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import br.com.caelum.vraptor.deserialization.Deserializer;
import br.com.caelum.vraptor.deserialization.Deserializes;
import br.com.caelum.vraptor.http.ParameterNameProvider;
import br.com.caelum.vraptor.resource.ResourceMethod;
import br.com.caelum.vraptor.view.ResultException;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
/**
*
* @author Renan Reis
* @author Guilherme Mangabeira
*/
@Deserializes({ "application/json", "json" })
@SuppressWarnings("rawtypes")
public class GsonDeserialization implements Deserializer {
private static final Logger logger = LoggerFactory.getLogger(GsonDeserialization.class);
private final ParameterNameProvider paramNameProvider;
private final Collection<JsonDeserializer> adapters;
public GsonDeserialization(ParameterNameProvider paramNameProvider, List<JsonDeserializer> adapters) {
this.paramNameProvider = paramNameProvider;
this.adapters = adapters;
}
public Object[] deserialize(InputStream inputStream, ResourceMethod method) {
Method jMethod = method.getMethod();
Class<?>[] types = jMethod.getParameterTypes();
if (types.length == 0) {
throw new IllegalArgumentException(
"Methods that consumes representations must receive just one argument");
}
Gson gson = getGson();
Object[] params = new Object[types.length];
String[] parameterNames = paramNameProvider.parameterNamesFor(jMethod);
try {
String content = getContentOfStream(inputStream);
logger.debug("json retrieved: " + content);
JsonParser parser = new JsonParser();
JsonObject root = (JsonObject) parser.parse(content);
for (int i = 0; i < types.length; i++) {
String name = parameterNames[i];
JsonElement node = root.get(name);
if (node != null) {
params[i] = gson.fromJson(node, types[i]);
}
}
} catch (Exception e) {
throw new ResultException("Unable to deserialize data", e);
}
return params;
}
protected Gson getGson() {
GsonBuilder builder = new GsonBuilder();
for (JsonDeserializer<?> adapter : adapters) {
builder.registerTypeHierarchyAdapter(getAdapterType(adapter), adapter);
}
return builder.create();
}
private Class<?> getAdapterType(JsonDeserializer<?> adapter) {
Type[] genericInterfaces = adapter.getClass().getGenericInterfaces();
ParameterizedType type = (ParameterizedType) genericInterfaces[0];
Type actualType = type.getActualTypeArguments()[0];
return (Class<?>) actualType;
}
private String getContentOfStream(InputStream input) throws IOException {
StringBuilder content = new StringBuilder();
byte[] buffer = new byte[1024];
int readed = 0;
while ((readed = input.read(buffer)) != -1) {
content.append(new String(buffer, 0, readed));
}
return content.toString();
}
}