flink-formats-kafka/flink-json-debezium/src/main/java/org/apache/flink/formats/json/JsonDeserializationSchema.java

/*
 * 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 org.apache.flink.formats.json;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.serialization.AbstractDeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.util.function.SerializableSupplier;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

/** DeserializationSchema that deserializes a JSON String. */
@PublicEvolving
public class JsonDeserializationSchema<T> extends AbstractDeserializationSchema<T> {

    private static final long serialVersionUID = 1L;

    private final Class<T> clazz;
    private final SerializableSupplier<ObjectMapper> mapperFactory;
    protected transient ObjectMapper mapper;

    public JsonDeserializationSchema(Class<T> clazz) {
        this(clazz, () -> new ObjectMapper());
    }

    public JsonDeserializationSchema(TypeInformation<T> typeInformation) {
        this(typeInformation, () -> new ObjectMapper());
    }

    public JsonDeserializationSchema(
            Class<T> clazz, SerializableSupplier<ObjectMapper> mapperFactory) {
        super(clazz);
        this.clazz = clazz;
        this.mapperFactory = mapperFactory;
    }

    public JsonDeserializationSchema(
            TypeInformation<T> typeInformation, SerializableSupplier<ObjectMapper> mapperFactory) {
        super(typeInformation);
        this.clazz = typeInformation.getTypeClass();
        this.mapperFactory = mapperFactory;
    }

    @Override
    public void open(InitializationContext context) {
        mapper = mapperFactory.get();
    }

    @Override
    public T deserialize(byte[] message) throws IOException {
        return mapper.readValue(message, clazz);
    }
}