ServiceIdMigrationTest

import static org.assertj.core.api.Assertions.assertThat;

import java.io.IOException;
import java.time.LocalDate;
import java.util.Objects;

import org.junit.Test;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.TreeNode;
import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.DeserializationConfig;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.BeanDeserializerModifier;
import com.fasterxml.jackson.databind.module.SimpleDeserializers;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.TreeTraversingParser;
import com.fasterxml.jackson.databind.node.ValueNode;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
public class ServiceIdMigrationTest {

    @Test
    public void unmarshalsServiceId() throws JsonProcessingException, IOException {
        final ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, true);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        final String test = "{\"reference\" : {\"number\" : \"one\", \"startDate\" : [2016, 11, 16]}, \"serviceId\" : \"0815\"}";
        final Container container = objectMapper.readerFor(Container.class).readValue(test);
        assertThat(container.serviceId).isEqualTo("0815");
    }

    @Test
    public void migratesViaDeserializerAndUnmarshalsServiceId() throws JsonProcessingException, IOException {
        final ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.registerModule(new ServiceIdMigratingContainerDeserializerModule());
        objectMapper.configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, true);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        final String test = "{\"reference\" : {\"number\" : \"one\", \"startDate\" : [2016, 11, 16], \"serviceId\" : \"0815\"}}";
        final Container container = objectMapper.readerFor(Container.class).readValue(test);
        assertThat(container.serviceId).isEqualTo("0815");
    }

    @Test
    public void migratesViaDeserializerModifierAndUnmarshalsServiceId() throws JsonProcessingException, IOException {
        final ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new JavaTimeModule());
        objectMapper.registerModule(new ServiceIdMigrationBeanDeserializerModifierModule());
        objectMapper.configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, true);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        final String test = "{\"reference\" : {\"number\" : \"one\", \"startDate\" : [2016, 11, 16], \"serviceId\" : \"0815\"}}";
        final Container container = objectMapper.readerFor(Container.class).readValue(test);
        assertThat(container.serviceId).isEqualTo("0815");
    }

    public final static class Container {

        public final Reference reference;

        public final String serviceId;

        @JsonCreator
        public Container(@JsonProperty("reference") Reference reference, @JsonProperty("serviceId") String serviceId) {
            this.reference = reference;
            this.serviceId = serviceId;
        }

        @Override
        public int hashCode() {
            return Objects.hash(this.reference, this.serviceId);
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Container that = (Container) obj;
            return Objects.equals(this.reference, that.reference) && Objects.equals(this.serviceId, that.serviceId);
        }
    }

    public final static class Reference {

        public final String number;

        public final LocalDate startDate;

        @JsonCreator
        public Reference(@JsonProperty("number") String number, @JsonProperty("startDate") LocalDate startDate) {
            this.number = number;
            this.startDate = startDate;
        }

        @Override
        public int hashCode() {
            return Objects.hash(this.number, this.startDate);
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Reference that = (Reference) obj;
            return Objects.equals(this.number, that.number) && Objects.equals(this.startDate, that.startDate);
        }

    }

    public static class ServiceIdMigratingContainerDeserializerModule extends Module {

        @Override
        public String getModuleName() {
            return "serviceid_migration";
        }

        @Override
        public Version version() {
            return new Version(0, 0, 1, "NONE", null, null);
        }

        @Override
        public void setupModule(SetupContext context) {
            context.addDeserializers(new SimpleDeserializers() {
                {
                    addDeserializer(Container.class, new ServiceIdMigratingContainerDeserializer());
                }
            });
        }
    }

    public static class ServiceIdMigratingContainerDeserializer extends JsonDeserializer<Container> {

        private final ObjectMapper objectMapper;

        {
            objectMapper = new ObjectMapper();
            objectMapper.registerModule(new JavaTimeModule());
            objectMapper.configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, true);
            objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        }

        @Override
        public Container deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
            ObjectNode node = p.readValueAsTree();
            migrate(node);
            return objectMapper.treeToValue(node, Container.class);
        }

        private void migrate(ObjectNode containerNode) {
            TreeNode referenceNode = containerNode.get("reference");
            if (referenceNode != null && referenceNode.isObject()) {
                TreeNode serviceIdNode = containerNode.get("serviceId");
                if (serviceIdNode == null) {
                    TreeNode referenceServiceIdNode = referenceNode.get("serviceId");
                    if (referenceServiceIdNode != null && referenceServiceIdNode.isValueNode()) {
                        containerNode.set("serviceId", (ValueNode) referenceServiceIdNode);
                    }
                }
            }
        }
    }

    public static class ServiceIdMigrationBeanDeserializerModifierModule extends Module {

        @Override
        public String getModuleName() {
            return "serviceid_migration";
        }

        @Override
        public Version version() {
            return new Version(0, 0, 1, "NONE", null, null);
        }

        @Override
        public void setupModule(SetupContext context) {
            context.addBeanDeserializerModifier(new ServiceIdMigrationBeanDeserializerModifier());
        }
    }


    public static class ServiceIdMigrationBeanDeserializerModifier extends BeanDeserializerModifier {

        @Override
        public JsonDeserializer<?> modifyDeserializer(DeserializationConfig config, BeanDescription beanDesc,
                JsonDeserializer<?> defaultDeserializer) {
            if (beanDesc.getBeanClass() == Container.class) {
                return new ModifiedServiceIdMigratingContainerDeserializer((JsonDeserializer<Container>) defaultDeserializer);
            } else {
                return defaultDeserializer;
            }
        }
    }

    public static class ModifiedServiceIdMigratingContainerDeserializer extends JsonDeserializer<Container> {

        private final JsonDeserializer<Container> defaultDeserializer;

        public ModifiedServiceIdMigratingContainerDeserializer(JsonDeserializer<Container> defaultDeserializer) {
            this.defaultDeserializer = defaultDeserializer;
        }

        @Override
        public Container deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
            ObjectNode node = p.readValueAsTree();
            migrate(node);
            return defaultDeserializer.deserialize(new TreeTraversingParser(node, p.getCodec()), ctxt);
        }

        private void migrate(ObjectNode containerNode) {
            TreeNode referenceNode = containerNode.get("reference");
            if (referenceNode != null && referenceNode.isObject()) {
                TreeNode serviceIdNode = containerNode.get("serviceId");
                if (serviceIdNode == null) {
                    TreeNode referenceServiceIdNode = referenceNode.get("serviceId");
                    if (referenceServiceIdNode != null && referenceServiceIdNode.isValueNode()) {
                        containerNode.set("serviceId", (ValueNode) referenceServiceIdNode);
                    }
                }
            }
        }
    }
}