org.jddd.jackson.SimpleValueObjectSerializerModifier.java Source code

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Here is the source code for org.jddd.jackson.SimpleValueObjectSerializerModifier.java

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/*
 * Copyright 2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jddd.jackson;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.List;
import java.util.Optional;

import org.jddd.annotation.ValueObject;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.ReflectionUtils;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.introspect.ClassIntrospector;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
import com.fasterxml.jackson.databind.ser.BeanSerializerBuilder;
import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;

/**
 * {@link BeanSerializerModifier} to serialize properties that are {@link ValueObject}s which in turn only carry a
 * single attribute as just that attribute.
 * 
 * @author Oliver Gierke
 */
public class SimpleValueObjectSerializerModifier extends BeanSerializerModifier {

    /* 
     * (non-Javadoc)
     * @see com.fasterxml.jackson.databind.ser.BeanSerializerModifier#updateBuilder(com.fasterxml.jackson.databind.SerializationConfig, com.fasterxml.jackson.databind.BeanDescription, com.fasterxml.jackson.databind.ser.BeanSerializerBuilder)
     */
    @Override
    public BeanSerializerBuilder updateBuilder(SerializationConfig config, BeanDescription beanDesc,
            BeanSerializerBuilder builder) {

        for (BeanPropertyWriter writer : builder.getProperties()) {

            JavaType propertyType = writer.getMember().getType();
            Class<?> type = propertyType.getRawClass();
            List<BeanPropertyDefinition> properties = getProperties(propertyType, config);

            Optional.ofNullable(AnnotationUtils.findAnnotation(type, ValueObject.class))//
                    .filter(it -> properties.size() == 1)//
                    .flatMap(it -> properties.stream().findFirst())//
                    .ifPresent(it -> writer.assignSerializer(new PropertyAccessingSerializer(it)));
        }

        return builder;
    }

    private static List<BeanPropertyDefinition> getProperties(JavaType type, SerializationConfig config) {

        ClassIntrospector classIntrospector = config.getClassIntrospector();
        BeanDescription description = classIntrospector.forSerialization(config, type, config);

        return description.findProperties();
    }

    private static class PropertyAccessingSerializer extends StdSerializer<Object> {

        private static final long serialVersionUID = 271400108881186699L;

        private final BeanPropertyDefinition property;

        public PropertyAccessingSerializer(BeanPropertyDefinition property) {

            super(Object.class);
            this.property = property;
        }

        /* 
         * (non-Javadoc)
         * @see com.fasterxml.jackson.databind.ser.std.StdSerializer#serialize(java.lang.Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)
         */
        @Override
        public void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException {

            AnnotatedMember accessor = property.getAccessor();
            makeAccessible(accessor.getMember());

            Object propertyValue = accessor.getValue(value);

            provider.findValueSerializer(propertyValue.getClass()).serialize(propertyValue, gen, provider);
        }

        private static void makeAccessible(Member member) {

            if (member instanceof Field) {
                ReflectionUtils.makeAccessible((Field) member);
            }

            if (member instanceof Method) {
                ReflectionUtils.makeAccessible((Method) member);
            }
        }
    }
}