org.apache.calcite.avatica.remote.JsonHandler Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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 org.apache.calcite.avatica.remote;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.io.StringWriter;
/**
* Implementation of {@link org.apache.calcite.avatica.remote.Handler}
* that decodes JSON requests, sends them to a {@link Service},
* and encodes the responses into JSON.
*
* @see org.apache.calcite.avatica.remote.JsonService
*/
public class JsonHandler implements Handler {
private final Service service;
protected static final ObjectMapper MAPPER = JsonService.MAPPER;
public JsonHandler(Service service) {
this.service = service;
}
public String apply(String jsonRequest) {
try {
Service.Request request = decode(jsonRequest, Service.Request.class);
final Service.Response response = request.accept(service);
return encode(response);
} catch (IOException e) {
throw handle(e);
}
}
private T decode(String request, Class valueType) throws IOException {
return MAPPER.readValue(request, valueType);
}
private String encode(T response) throws IOException {
final StringWriter w = new StringWriter();
MAPPER.writeValue(w, response);
return w.toString();
}
protected RuntimeException handle(IOException e) {
return new RuntimeException(e);
}
}
// End JsonHandler.java