org.kitesdk.data.spi.filesystem.AvroAppender.java Source code

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Here is the source code for org.kitesdk.data.spi.filesystem.AvroAppender.java

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/**
 * Copyright 2013 Cloudera Inc.
 *
 * 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 org.kitesdk.data.spi.filesystem;

import com.google.common.base.Objects;
import com.google.common.io.Closeables;
import java.io.IOException;
import org.apache.avro.Schema;
import org.apache.avro.file.CodecFactory;
import org.apache.avro.file.DataFileWriter;
import org.apache.avro.io.DatumWriter;
import org.apache.avro.reflect.ReflectDatumWriter;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.kitesdk.compat.Hadoop;

class AvroAppender<E> implements FileSystemWriter.FileAppender<E> {

    private final Schema schema;
    private final FileSystem fileSystem;
    private final Path path;
    private final boolean enableCompression;

    private FSDataOutputStream out = null;
    private DataFileWriter<E> dataFileWriter = null;
    private DatumWriter<E> writer = null;

    public AvroAppender(FileSystem fileSystem, Path path, Schema schema, boolean enableCompression) {
        this.fileSystem = fileSystem;
        this.path = path;
        this.schema = schema;
        this.enableCompression = enableCompression;
    }

    @Override
    public void open() throws IOException {
        writer = new ReflectDatumWriter<E>();
        dataFileWriter = new DataFileWriter<E>(writer);

        /*
         * We may want to expose the codec in the writer and simply rely on the
         * builder and proper instantiation from dataset-level configuration.
         * Hard-coding snappy seems a little too draconian.
         */
        if (enableCompression) {
            dataFileWriter.setCodec(CodecFactory.snappyCodec());
        }

        out = fileSystem.create(path, true);
        dataFileWriter.create(schema, out);
    }

    @Override
    public void append(E entity) throws IOException {
        dataFileWriter.append(entity);
    }

    @Override
    public void flush() throws IOException {
        dataFileWriter.flush();
        Hadoop.FSDataOutputStream.hflush.invoke(out);
    }

    @Override
    public void close() throws IOException {
        Closeables.close(dataFileWriter, false);
    }

    @Override
    public void cleanup() throws IOException {
        // No cleanup tasks needed
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).add("path", path).add("schema", schema).add("fileSystem", fileSystem)
                .add("enableCompression", enableCompression).add("dataFileWriter", dataFileWriter)
                .add("writer", writer).toString();
    }
}