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/*
 * 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.Internal;
import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.formats.common.TimestampFormat;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.types.logical.DecimalType;
import org.apache.flink.table.types.logical.RowType;
import org.apache.flink.table.types.logical.utils.LogicalTypeChecks;
import org.apache.flink.util.jackson.JacksonMapperFactory;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.core.json.JsonReadFeature;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.DeserializationFeature;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.JsonNode;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;

import javax.annotation.Nullable;

import java.io.IOException;
import java.util.Objects;

import static java.lang.String.format;
import static org.apache.flink.util.Preconditions.checkNotNull;

/**
 * Deserialization schema from JSON to Flink Table/SQL internal data structure {@link RowData}.
 *
 * Deserializes a byte[] message as a JSON object and reads the specified fields.
 *
 * Failures during deserialization are forwarded as wrapped IOExceptions.
 */
@Internal
public class JsonRowDataDeserializationSchema implements DeserializationSchema {
    private static final long serialVersionUID = 1L;

    /** Flag indicating whether to fail if a field is missing. */
    private final boolean failOnMissingField;

    /** Flag indicating whether to ignore invalid fields/rows (default: throw an exception). */
    private final boolean ignoreParseErrors;

    /** TypeInformation of the produced {@link RowData}. */
    private final TypeInformation resultTypeInfo;

    /**
     * Runtime converter that converts {@link JsonNode}s into objects of Flink SQL internal data
     * structures.
     */
    private final JsonToRowDataConverters.JsonToRowDataConverter runtimeConverter;

    /** Object mapper for parsing the JSON. */
    private transient ObjectMapper objectMapper;

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

    private final boolean hasDecimalType;

    public JsonRowDataDeserializationSchema(
            RowType rowType,
            TypeInformation resultTypeInfo,
            boolean failOnMissingField,
            boolean ignoreParseErrors,
            TimestampFormat timestampFormat) {
        if (ignoreParseErrors && failOnMissingField) {
            throw new IllegalArgumentException(
                    "JSON format doesn't support failOnMissingField and ignoreParseErrors are both enabled.");
        }
        this.resultTypeInfo = checkNotNull(resultTypeInfo);
        this.failOnMissingField = failOnMissingField;
        this.ignoreParseErrors = ignoreParseErrors;
        this.runtimeConverter =
                new JsonToRowDataConverters(failOnMissingField, ignoreParseErrors, timestampFormat)
                        .createConverter(checkNotNull(rowType));
        this.timestampFormat = timestampFormat;
        this.hasDecimalType = LogicalTypeChecks.hasNested(rowType, t -> t instanceof DecimalType);
    }

    @Override
    public void open(InitializationContext context) throws Exception {
        objectMapper =
                JacksonMapperFactory.createObjectMapper()
                        .configure(
                                JsonReadFeature.ALLOW_UNESCAPED_CONTROL_CHARS.mappedFeature(),
                                true);
        if (hasDecimalType) {
            objectMapper.enable(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS);
        }
    }

    @Override
    public RowData deserialize(@Nullable byte[] message) throws IOException {
        if (message == null) {
            return null;
        }
        try {
            return convertToRowData(deserializeToJsonNode(message));
        } catch (Throwable t) {
            if (ignoreParseErrors) {
                return null;
            }
            throw new IOException(
                    format("Failed to deserialize JSON '%s'.", new String(message)), t);
        }
    }

    public JsonNode deserializeToJsonNode(byte[] message) throws IOException {
        return objectMapper.readTree(message);
    }

    public RowData convertToRowData(JsonNode message) {
        return (RowData) runtimeConverter.convert(message);
    }

    @Override
    public boolean isEndOfStream(RowData nextElement) {
        return false;
    }

    @Override
    public TypeInformation getProducedType() {
        return resultTypeInfo;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        JsonRowDataDeserializationSchema that = (JsonRowDataDeserializationSchema) o;
        return failOnMissingField == that.failOnMissingField
                && ignoreParseErrors == that.ignoreParseErrors
                && resultTypeInfo.equals(that.resultTypeInfo)
                && timestampFormat.equals(that.timestampFormat);
    }

    @Override
    public int hashCode() {
        return Objects.hash(failOnMissingField, ignoreParseErrors, resultTypeInfo, timestampFormat);
    }
}