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1 | /* |
2 | * Licensed to the Apache Software Foundation (ASF) under one or more | |
3 | * contributor license agreements. See the NOTICE file distributed with | |
4 | * this work for additional information regarding copyright ownership. | |
5 | * The ASF licenses this file to You under the Apache License, Version 2.0 | |
6 | * (the "License"); you may not use this file except in compliance with | |
7 | * the License. You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, software | |
12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 | * See the License for the specific language governing permissions and | |
15 | * limitations under the License. | |
16 | */ | |
17 | ||
18 | package org.apache.arrow.vector.util; | |
19 | ||
20 | import java.util.LinkedHashMap; | |
21 | ||
22 | import com.fasterxml.jackson.core.JsonProcessingException; | |
23 | import com.fasterxml.jackson.databind.ObjectMapper; | |
24 | ||
25 | /** | |
26 | * Simple class that extends the regular java.util.HashMap but overrides the | |
27 | * toString() method of the HashMap class to produce a JSON string instead | |
28 | * | |
29 | * @param <K> The type of the key for the map. | |
30 | * @param <V> The type of the value for the map. | |
31 | */ | |
32 | public class JsonStringHashMap<K, V> extends LinkedHashMap<K, V> { | |
33 | ||
34 | private static ObjectMapper mapper; | |
35 | ||
36 | static { | |
37 | mapper = new ObjectMapper(); | |
38 | } | |
39 | ||
40 | @Override | |
41 | public final String toString() { | |
42 | try { | |
43 | return mapper.writeValueAsString(this); | |
44 | } catch (JsonProcessingException e) { | |
45 | throw new IllegalStateException("Cannot serialize hash map to JSON string", e); | |
46 | } | |
47 | } | |
48 | } |