1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements.  See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership.  The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the
7  * "License"); you may not use this file except in compliance
8  * with the License.  You may obtain a copy of the License at
9  *
10  *     http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 
19 package org.apache.zookeeper.server.admin;
20 
21 import com.fasterxml.jackson.core.JsonGenerationException;
22 import com.fasterxml.jackson.databind.JsonMappingException;
23 import com.fasterxml.jackson.databind.ObjectMapper;
24 import com.fasterxml.jackson.databind.PropertyNamingStrategy;
25 import com.fasterxml.jackson.databind.SerializationFeature;
26 import java.io.IOException;
27 import java.io.PrintWriter;
28 import org.slf4j.Logger;
29 import org.slf4j.LoggerFactory;
30 
31 public class JsonOutputter implements CommandOutputter {
32 
33     static final Logger LOG = LoggerFactory.getLogger(JsonOutputter.class);
34 
35     public static final String ERROR_RESPONSE = "{\"error\": \"Exception writing command response to JSON\"}";
36 
37     private ObjectMapper mapper;
38 
JsonOutputter()39     public JsonOutputter() {
40         mapper = new ObjectMapper();
41         mapper.configure(SerializationFeature.WRITE_ENUMS_USING_TO_STRING, true);
42         mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
43         mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
44     }
45 
46     @Override
getContentType()47     public String getContentType() {
48         return "application/json";
49     }
50 
51     @Override
output(CommandResponse response, PrintWriter pw)52     public void output(CommandResponse response, PrintWriter pw) {
53         try {
54             mapper.writeValue(pw, response.toMap());
55         } catch (JsonGenerationException e) {
56             LOG.warn("Exception writing command response to JSON:", e);
57             pw.write(ERROR_RESPONSE);
58         } catch (JsonMappingException e) {
59             LOG.warn("Exception writing command response to JSON:", e);
60             pw.write(ERROR_RESPONSE);
61         } catch (IOException e) {
62             LOG.warn("Exception writing command response to JSON:", e);
63             pw.write(ERROR_RESPONSE);
64         }
65     }
66 
67 }
68