JacksonMessageReader.java

/*
 * Copyright 2022 Proto Utils 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.jackson.sio;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.protobuf.Descriptors;
import com.google.protobuf.Message;
import net.morimekta.proto.ProtoMessage;
import net.morimekta.proto.jackson.ProtoModule;
import net.morimekta.proto.sio.MessageReader;

import java.io.IOException;
import java.io.Reader;

import static java.util.Objects.requireNonNull;

/**
 * Reader to use jackson object mapper to parse messages.
 */
public class JacksonMessageReader implements MessageReader {
    private final Reader       reader;
    private final ObjectMapper mapper;

    /**
     * Create reader with given object mapper.
     *
     * @param reader The reader to read from.
     * @param mapper The object mapper.
     */
    public JacksonMessageReader(Reader reader, ObjectMapper mapper) {
        this.reader = requireNonNull(reader, "reader == null");
        this.mapper = requireNonNull(mapper, "mapper == null").registerModule(new ProtoModule());
    }

    /** {@inheritDoc} */
    @Override
    public Message read(Descriptors.Descriptor descriptor) throws IOException {
        var type = ProtoMessage.getMessageClass(descriptor);
        return mapper.readValue(reader, type);
    }
}