JsonRowDataSerializationSchema.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.wikimedia.eventutilities.flink.formats.json;

import java.util.Locale;
import java.util.Objects;
import java.util.function.Consumer;
import java.util.function.Function;

import org.apache.flink.api.common.serialization.SerializationSchema;
import org.apache.flink.formats.common.TimestampFormat;
import org.apache.flink.formats.json.JsonFormatOptions;
import org.apache.flink.formats.json.JsonRowDataDeserializationSchema;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.types.logical.RowType;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import lombok.EqualsAndHashCode;

/**
 * Serialization schema that serializes an object of Flink internal data structure into a JSON
 * bytes.
 *
 * <p>Serializes the input Flink object into a JSON string and converts it into <code>byte[]</code>.
 *
 * <p>Result <code>byte[]</code> messages can be deserialized using {@link
 * JsonRowDataDeserializationSchema}.
 * <p>
 * NOTE: This class was directly copied and modified from upstream Flink in order to
 * use unshaded Jackson dependencies for use with eventutilities-core.
 * <p>
 * WMF changes from upstream Flink:
 * - Use unshaded jackson dependencies.
 * - added normalization function support
 */
// Suppress all spotbugs warnings for this class, as it was copy/pasted from upstream Flink.
@SuppressFBWarnings
@SuppressWarnings({"checkstyle:ClassFanoutComplexity", "checkstyle:CyclomaticComplexity"})
@EqualsAndHashCode
public class JsonRowDataSerializationSchema implements SerializationSchema<RowData> {
    private static final long serialVersionUID = 1L;

    /**
     * RowType to generate the runtime converter.
     */
    private final RowType rowType;

    /**
     * Event generator responsible for fetching the schema and validating the event against it.
     */
    private final Function<Consumer<ObjectNode>, ObjectNode> normalization;

    /**
     * The converter that converts internal data formats to JsonNode.
     */
    private final RowDataToJsonConverters.RowDataToJsonConverter runtimeConverter;

    /**
     * Object mapper that is used to create output JSON objects.
     */
    private final ObjectMapper mapper;

    /**
     * Reusable object node.
     */
    private transient ObjectNode node;

    /**
     * Timestamp format specification which is used to parse timestamp.
     */
    private final TimestampFormat timestampFormat;

    /**
     * The handling mode when serializing null keys for map data.
     */
    private final JsonFormatOptions.MapNullKeyMode mapNullKeyMode;

    /**
     * The string literal when handling mode for map null key LITERAL.
     */
    private final String mapNullKeyLiteral;

    /**
     * Flag indicating whether to serialize all decimals as plain numbers.
     */
    private final boolean encodeDecimalAsPlainNumber;

    public JsonRowDataSerializationSchema(
        RowType rowType,
        Function<Consumer<ObjectNode>, ObjectNode> normalization,
        ObjectMapper mapper,
        TimestampFormat timestampFormat,
        JsonFormatOptions.MapNullKeyMode mapNullKeyMode,
        String mapNullKeyLiteral,
        boolean encodeDecimalAsPlainNumber) {
        this.rowType = rowType;
        this.normalization = normalization;
        this.mapper = mapper;
        this.timestampFormat = timestampFormat;
        this.mapNullKeyMode = mapNullKeyMode;
        this.mapNullKeyLiteral = mapNullKeyLiteral;
        this.encodeDecimalAsPlainNumber = encodeDecimalAsPlainNumber;
        this.runtimeConverter =
            new RowDataToJsonConverters(timestampFormat, mapNullKeyMode, mapNullKeyLiteral)
                .createConverter(rowType);

        mapper.configure(
            JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN, encodeDecimalAsPlainNumber);
    }

    @SuppressWarnings("checkstyle:IllegalCatch")
    @Override
    public byte[] serialize(RowData row) {
        if (node == null) {
            node = mapper.createObjectNode();
        }

        try {
            ObjectNode event = normalization.apply(root -> runtimeConverter.convert(mapper, root, row));
            return mapper.writeValueAsBytes(event);
        } catch (Throwable t) {
            throw new RuntimeException(String.format(Locale.ROOT, "Could not serialize row '%s'.", row), t);
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        JsonRowDataSerializationSchema that = (JsonRowDataSerializationSchema) o;
        return rowType.equals(that.rowType)
            && timestampFormat.equals(that.timestampFormat)
            && mapNullKeyMode.equals(that.mapNullKeyMode)
            && mapNullKeyLiteral.equals(that.mapNullKeyLiteral)
            && encodeDecimalAsPlainNumber == that.encodeDecimalAsPlainNumber;
    }

    @Override
    public int hashCode() {
        return Objects.hash(
            rowType,
            timestampFormat,
            mapNullKeyMode,
            mapNullKeyLiteral,
            encodeDecimalAsPlainNumber);
    }
}