LombokBuilderBeanReader.java

/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

package com.fasterxml.jackson.jr.ob.impl;

import com.amazon.aws.iot.greengrass.JsonBuilder;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.jr.ob.JSONObjectException;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.Optional;

public class LombokBuilderBeanReader extends BeanReader {

    private final Optional<Class<?>> builderClass;
    private final Optional<Method> builderMethod;
    private final Optional<Method> buildMethod;

    public LombokBuilderBeanReader(Class<?> type, BeanReader defaultReader) {
        super(type, defaultReader._propsByName, defaultReader._defaultCtor, defaultReader._stringCtor,
                defaultReader._longCtor, defaultReader._ignorableNames, defaultReader._aliasMapping);

        // To use Lombok builder for deserialization, the builder must be annotated with @JsonBuilder
        builderClass =
                Arrays.stream(_valueType.getDeclaredClasses())
                        .filter(a -> a.getAnnotation(JsonBuilder.class) != null)
                        .findFirst();
        builderMethod = builderClass.flatMap(builderClass -> Arrays.stream(_valueType.getDeclaredMethods())
                .filter(m -> m.getName().equals("builder") && m.getParameterCount() == 0)
                .findFirst());
        buildMethod = builderClass.flatMap(builderClass -> Arrays.stream(builderClass.getDeclaredMethods())
                .filter(n -> n.getName().equals("build") && n.getParameterCount() == 0)
                .findFirst());
    }

    @Override
    public BeanPropertyReader findProperty(String name) {
        return wrapReader(super.findProperty(name));
    }

    private BeanPropertyReader wrapReader(BeanPropertyReader beanPropertyReader) {
        if (beanPropertyReader == null) {
            return beanPropertyReader;
        }
        if (builderClass.isPresent()) {
            Method setter;
            try {
                // Find builder setter for the type or any super type
                setter = Arrays.stream(builderClass.get().getDeclaredMethods())
                        .filter(n -> n.getName().equals(beanPropertyReader.getName()) && n.getParameterCount() == 1 && n
                                .getParameterTypes()[0].isAssignableFrom(beanPropertyReader.rawSetterType()))
                        .findFirst().get();
            } catch (NoSuchElementException e) {
                try {
                    setter = builderClass.get().getDeclaredMethod(beanPropertyReader.getName(), String.class);
                } catch (NoSuchMethodException ex) {
                    return beanPropertyReader;
                }
            }
            return new BeanPropertyReader(beanPropertyReader.getName(), null, setter)
                    .withReader(beanPropertyReader.getReader());
        }
        return beanPropertyReader;
    }

    @Override
    protected Object create() throws Exception {
        if (builderClass.isPresent() && builderMethod.isPresent()) {
            return builderMethod.get().invoke(null, (Object[]) null);
        }
        return super.create();
    }

    @Override
    public Object readNext(JSONReader r, JsonParser p) throws IOException {
        Object b = super.readNext(r, p);
        return runBuildOnBuilder(p, b);
    }

    @Override
    public Object read(JSONReader reader, JsonParser p) throws IOException {
        Object b = super.read(reader, p);
        return runBuildOnBuilder(p, b);
    }

    private Object runBuildOnBuilder(JsonParser p, Object b) throws IOException {
        if (b == null) {
            return b;
        }
        if (buildMethod.isPresent()) {
            try {
                return buildMethod.get().invoke(b, (Object[]) null);
            } catch (InvocationTargetException | IllegalAccessException e) {
                throw JSONObjectException.from(p, e.getCause() == null ? e : e.getCause(),
                        e.getCause() == null ? e.getMessage() : e.getCause().getMessage());
            }
        }
        return b;
    }
}