gobblin.converter.json.JsonStringToJsonIntermediateConverter.java Source code

Introduction

Here is the source code for gobblin.converter.json.JsonStringToJsonIntermediateConverter.java

Source

/*
 * 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 gobblin.converter.json;

import gobblin.configuration.WorkUnitState;
import gobblin.converter.Converter;
import gobblin.converter.DataConversionException;
import gobblin.converter.SchemaConversionException;
import gobblin.converter.SingleRecordIterable;

import java.io.IOException;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Lists;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

/**
 * Converts a json string to a {@link JsonObject}.
 */
public class JsonStringToJsonIntermediateConverter extends Converter<String, JsonArray, String, JsonObject> {

    private final static Logger log = LoggerFactory.getLogger(JsonStringToJsonIntermediateConverter.class);

    private static final String UNPACK_COMPLEX_SCHEMAS_KEY = "gobblin.converter.jsonStringToJsonIntermediate.unpackComplexSchemas";

    private boolean unpackComplexSchemas;

    /**
     * Take in an input schema of type string, the schema must be in JSON format
     * @return a JsonArray representation of the schema
     */
    @Override
    public JsonArray convertSchema(String inputSchema, WorkUnitState workUnit) throws SchemaConversionException {
        this.unpackComplexSchemas = workUnit.getPropAsBoolean(UNPACK_COMPLEX_SCHEMAS_KEY, true);

        JsonParser jsonParser = new JsonParser();
        log.info("Schema: " + inputSchema);
        JsonElement jsonSchema = jsonParser.parse(inputSchema);
        return jsonSchema.getAsJsonArray();
    }

    /**
     * Takes in a record with format String and Uses the inputSchema to convert the record to a JsonObject
     * @return a JsonObject representing the record
     * @throws IOException
     */
    @Override
    public Iterable<JsonObject> convertRecord(JsonArray outputSchema, String strInputRecord, WorkUnitState workUnit)
            throws DataConversionException {
        JsonParser jsonParser = new JsonParser();
        JsonObject inputRecord = (JsonObject) jsonParser.parse(strInputRecord);

        if (!this.unpackComplexSchemas) {
            return new SingleRecordIterable<>(inputRecord);
        }

        JsonObject outputRecord = new JsonObject();

        for (int i = 0; i < outputSchema.size(); i++) {
            String expectedColumnName = outputSchema.get(i).getAsJsonObject().get("columnName").getAsString();

            if (inputRecord.has(expectedColumnName)) {
                //As currently gobblin.converter.avro.JsonIntermediateToAvroConverter is not able to handle complex schema's so storing it as string

                if (inputRecord.get(expectedColumnName).isJsonArray()) {
                    outputRecord.addProperty(expectedColumnName, inputRecord.get(expectedColumnName).toString());
                } else if (inputRecord.get(expectedColumnName).isJsonObject()) {
                    //To check if internally in an JsonObject there is multiple hierarchy
                    boolean isMultiHierarchyInsideJsonObject = false;
                    for (Map.Entry<String, JsonElement> entry : ((JsonObject) inputRecord.get(expectedColumnName))
                            .entrySet()) {
                        if (entry.getValue().isJsonArray() || entry.getValue().isJsonObject()) {
                            isMultiHierarchyInsideJsonObject = true;
                            break;
                        }
                    }
                    if (isMultiHierarchyInsideJsonObject) {
                        outputRecord.addProperty(expectedColumnName,
                                inputRecord.get(expectedColumnName).toString());
                    } else {
                        outputRecord.add(expectedColumnName, inputRecord.get(expectedColumnName));
                    }

                } else {
                    outputRecord.add(expectedColumnName, inputRecord.get(expectedColumnName));
                }
            } else {
                outputRecord.add(expectedColumnName, JsonNull.INSTANCE);
            }

        }
        return new SingleRecordIterable<>(outputRecord);
    }
}