io.cdap.cdap.gateway.handlers.meta.AbstractRemoteSystemOpsHandler Maven / Gradle / Ivy
/*
* Copyright © 2016-2019 Cask Data, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package io.cdap.cdap.gateway.handlers.meta;
import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.reflect.TypeToken;
import io.cdap.cdap.common.BadRequestException;
import io.cdap.cdap.common.internal.remote.MethodArgument;
import io.cdap.http.AbstractHttpHandler;
import io.netty.handler.codec.http.FullHttpRequest;
import java.lang.reflect.Type;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.List;
import javax.annotation.Nullable;
/**
* Implements common functionality for reading method arguments and deserialize them.
*/
class AbstractRemoteSystemOpsHandler extends AbstractHttpHandler {
private static final Gson GSON = new Gson();
private static final Type METHOD_ARGUMENT_LIST_TYPE = new TypeToken>() { }.getType();
// we don't share the same version as other handlers in app fabric, so we can upgrade/iterate faster
protected static final String VERSION = "/v1";
Iterator parseArguments(FullHttpRequest request) {
String body = request.content().toString(StandardCharsets.UTF_8);
List arguments = GSON.fromJson(body, METHOD_ARGUMENT_LIST_TYPE);
return arguments.iterator();
}
@Nullable
T deserializeNext(Iterator arguments) throws ClassNotFoundException, BadRequestException {
return deserializeNext(arguments, null);
}
@Nullable
T deserializeNext(Iterator arguments,
@Nullable Type typeOfT) throws ClassNotFoundException, BadRequestException {
if (!arguments.hasNext()) {
throw new BadRequestException("Expected additional elements.");
}
MethodArgument argument = arguments.next();
if (argument == null) {
return null;
}
JsonElement value = argument.getValue();
if (value == null) {
return null;
}
if (typeOfT != null) {
return GSON.fromJson(value, typeOfT);
}
return GSON.fromJson(value, Class.forName(argument.getType()));
}
}