src/test/org/codehaus/jackson/failing/TestCustomMapKeySerializer.java

package org.codehaus.jackson.failing;

import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.annotate.JsonCreator;
import org.codehaus.jackson.annotate.JsonProperty;
import org.codehaus.jackson.map.*;
import org.codehaus.jackson.map.annotate.JsonDeserialize;
import org.codehaus.jackson.map.annotate.JsonSerialize;

public class TestCustomMapKeySerializer extends BaseMapTest
{
    // [JACKSON-882]
    public static class CustomKey {
        private final int id;

        public CustomKey(int id) {this.id = id;}

        public int getId() { return id; }
    }
    
    public static class Model
    {
        private final Map<CustomKey, String> map;

        @JsonCreator
        public Model(@JsonProperty("map") @JsonDeserialize(keyUsing = CustomKeyDeserializer.class) Map<CustomKey, String> map)
        {
            this.map = new HashMap<CustomKey, String>(map);
        }

        @JsonProperty
        @JsonSerialize(keyUsing = CustomKeySerializer.class)
        public Map<CustomKey, String> getMap() {
            return map;
        }
    }
     
    static class CustomKeySerializer extends JsonSerializer<CustomKey> {
        @Override
        public void serialize(CustomKey value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
            jgen.writeFieldName(String.valueOf(value.getId()));
        }
    }

    static class CustomKeyDeserializer extends KeyDeserializer {
        @Override
        public CustomKey deserializeKey(String key, DeserializationContext ctxt) throws IOException {
            return new CustomKey(Integer.valueOf(key));
        }
    }

    /*
    /**********************************************************
    /* Test methods
    /**********************************************************
     */

    public void testIssue882() throws Exception
    {
        Model original = new Model(Collections.singletonMap(new CustomKey(123), "test"));
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(original);
        Model deserialized = mapper.readValue(json, Model.class);
        
        System.out.println(original.getMap().equals(deserialized.getMap()));
    }

}