RegisterMessageMappers.java

/*
 * Copyright 2019 Providence Authors
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 net.morimekta.proto.jdbi.v3.annotations;

import com.google.protobuf.Descriptors;
import net.morimekta.collect.UnmodifiableMap;
import net.morimekta.proto.jdbi.v3.MessageRowMapper;
import org.jdbi.v3.sqlobject.customizer.SqlStatementCustomizer;
import org.jdbi.v3.sqlobject.customizer.SqlStatementCustomizerFactory;
import org.jdbi.v3.sqlobject.customizer.SqlStatementCustomizingAnnotation;

import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;

import static net.morimekta.proto.ProtoMessage.getMessageDescriptor;
import static net.morimekta.proto.jdbi.ProtoJdbi.getDefaultColumnName;

@Inherited
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
@SqlStatementCustomizingAnnotation(RegisterMessageMappers.Factory.class)
public @interface RegisterMessageMappers {
    RegisterMessageMapper[] value();

    class Factory implements SqlStatementCustomizerFactory {
        @Override
        public SqlStatementCustomizer createForType(Annotation annotation, Class<?> sqlObjectType) {
            RegisterMessageMappers registers = (RegisterMessageMappers) annotation;
            return createForAnnotations(registers.value());
        }

        @Override
        public SqlStatementCustomizer createForMethod(Annotation annotation, Class<?> sqlObjectType, Method method) {
            return createForType(annotation, sqlObjectType);
        }

        static SqlStatementCustomizer createForAnnotations(RegisterMessageMapper... annotations) {
            Map<Type, MessageRowMapper<?>> mappers = new HashMap<>();
            for (RegisterMessageMapper register : annotations) {
                Descriptors.Descriptor                   descriptor = getMessageDescriptor(register.value());
                Map<String, Descriptors.FieldDescriptor> fieldMap   = makeFieldMap(descriptor, register);
                MessageRowMapper<?>                      mapper     = new MessageRowMapper<>("", descriptor, fieldMap);
                mappers.put(register.value(), mapper);
            }
            return stmt -> mappers.forEach(stmt::registerRowMapper);
        }

        private static Map<String, Descriptors.FieldDescriptor> makeFieldMap(
                Descriptors.Descriptor descriptor,
                RegisterMessageMapper register) {
            UnmodifiableMap.Builder<String, Descriptors.FieldDescriptor> map = UnmodifiableMap.newBuilder();
            for (Descriptors.FieldDescriptor field : descriptor.getFields()) {
                map.put(getDefaultColumnName(field), field);
            }
            for (FieldColumn bind : register.fields()) {
                Descriptors.FieldDescriptor field = descriptor.findFieldByNumber(bind.field());
                if (field == null) {
                    throw new IllegalArgumentException(
                            "Field " + bind.field() + " not found in " + descriptor.getFullName());
                }
                map.put(bind.column(), field);
            }
            return map.build();
        }
    }
}