com.intropro.prairie.format.avro.AvroFormatReader Maven / Gradle / Ivy

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/**
 * Licensed 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 com.intropro.prairie.format.avro;

import com.intropro.prairie.format.AbstractFormatReader;
import org.apache.avro.Schema;
import org.apache.avro.file.DataFileReader;
import org.apache.avro.file.DataFileStream;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.DatumReader;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by presidentio on 10/7/15.
 */
public class AvroFormatReader extends AbstractFormatReader> {

    private InputStream inputStream;

    private DataFileReader dataFileReader;
    private DatumReader datumReader;
    private DataFileStream dataFileStream;

    private File tmpFile;

    AvroFormatReader(InputStream inputStream, Schema schema) {
        this.inputStream = inputStream;
        datumReader = schema == null ? new GenericDatumReader()
                : new GenericDatumReader(schema);
    }

    @Override
    public Map next() throws IOException {
        if (dataFileReader == null) {
            copyDataToTmpFile();
            dataFileStream = new DataFileStream<>(new FileInputStream(tmpFile), datumReader);
            dataFileReader = new DataFileReader<>(tmpFile, datumReader);
        }
        if (!dataFileStream.hasNext()) {
            return null;
        }
        GenericRecord genericRecord = dataFileStream.next();
        return parseRecord(genericRecord, genericRecord.getSchema());
    }

    private Object parseObject(Object object, Schema schema) throws IOException {
        switch (schema.getType()) {
            case BOOLEAN:
            case DOUBLE:
            case FLOAT:
            case INT:
            case LONG:
            case NULL:
                return object;
            case STRING:
                return object.toString();
            case RECORD:
                return parseRecord((GenericRecord) object, schema);
            case ARRAY:
                return parseList((List