001/*
002 * Copyright 2020 Global Biodiversity Information Facility (GBIF)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.gbif.api.jackson;
017
018import java.io.IOException;
019import java.util.AbstractMap;
020import java.util.Map;
021
022import com.fasterxml.jackson.core.JsonGenerator;
023import com.fasterxml.jackson.core.JsonParser;
024import com.fasterxml.jackson.databind.DeserializationContext;
025import com.fasterxml.jackson.databind.JsonDeserializer;
026import com.fasterxml.jackson.databind.JsonMappingException;
027import com.fasterxml.jackson.databind.JsonSerializer;
028import com.fasterxml.jackson.databind.SerializerProvider;
029
030/**
031 * <p>Jackson Serializer and Deserializer for {@link java.util.Map.Entry}.
032 * <p>This is mostly for pre 2.7 version of Jackson, see <a href="https://github.com/fasterxml/jackson-databind/issues/565">Jackson Databind issue 565</a>.
033 *
034 * <p>The goal is to omit the key/value field name since they are implicit
035 * for a Map.Entry.
036 *
037 * <code>{"key":"mykey","value":18}</code> becomes <code>{"mykey":18}</code>
038 *
039 * <p>The key will use <code>toString()</code> and the value can only be a String or a Number (int or float) for now.
040 *
041 * <pre>
042 * // Usage for lists:
043 * &#64;JsonSerialize(contentUsing = MapEntrySerde.MapEntryJsonSerializer.class)
044 * public List<Map.Entry<String, Object>> getKeyValueList() { ... };
045 * </pre>
046 */
047@Deprecated
048public class MapEntrySerde {
049
050  @Deprecated
051  public static class MapEntryJsonSerializer extends JsonSerializer<Map.Entry<Object, Object>> {
052
053    @Override
054    public void serialize(Map.Entry<Object, Object> value, JsonGenerator jgen,
055                          SerializerProvider serializerProvider) throws IOException {
056      if (value == null) {
057        jgen.writeNull();
058        return;
059      }
060      jgen.writeStartObject();
061      jgen.writeFieldName(value.getKey().toString());
062      jgen.writeObject(value.getValue());
063      jgen.writeEndObject();
064    }
065  }
066
067  @Deprecated
068  public static class MapEntryJsonDeserializer extends JsonDeserializer<Map.Entry<Object, Object>> {
069    @Override
070    public Map.Entry<Object, Object> deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {
071      String tmp = jp.getText(); // {
072      jp.nextToken();
073      String key = jp.getText();
074      jp.nextToken();
075      Object value;
076
077      switch (jp.getCurrentToken()) {
078        case VALUE_STRING:
079          value = jp.getText();
080          break;
081        case VALUE_NUMBER_INT:
082          value = jp.getIntValue();
083          break;
084        case VALUE_NUMBER_FLOAT:
085          value = jp.getFloatValue();
086          break;
087        default:
088          throw JsonMappingException.from(jp, "Expected String or Number");
089      }
090      jp.nextToken();
091      tmp = jp.getText(); // }
092
093      return new AbstractMap.SimpleImmutableEntry<>(key, value);
094    }
095  }
096}