org.kitesdk.data.spi.Schemas.java Source code

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Here is the source code for org.kitesdk.data.spi.Schemas.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;

import com.google.common.io.Closeables;
import com.google.common.io.Resources;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import org.apache.avro.Schema;
import org.apache.avro.file.DataFileStream;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericRecord;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import parquet.avro.AvroSchemaConverter;
import parquet.hadoop.ParquetFileReader;
import parquet.hadoop.metadata.ParquetMetadata;

public class Schemas {
    // used to match resource:schema.avsc URIs
    private static final String RESOURCE_URI_SCHEME = "resource";

    public static Schema fromAvsc(InputStream in) throws IOException {
        // the parser has state, so use a new one each time
        return new Schema.Parser().parse(in);
    }

    public static Schema fromAvsc(File location) throws IOException {
        return fromAvsc(FileSystem.getLocal(DefaultConfiguration.get()), new Path(location.getPath()));
    }

    public static Schema fromAvsc(FileSystem fs, Path path) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = fs.open(path);
            Schema schema = new Schema.Parser().parse(in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    public static Schema fromAvsc(Configuration conf, URI location) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = open(conf, location);
            Schema schema = fromAvsc(in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    public static Schema fromAvro(InputStream in) throws IOException {
        GenericDatumReader<GenericRecord> datumReader = new GenericDatumReader<GenericRecord>();
        DataFileStream<GenericRecord> stream = null;
        boolean threw = true;

        try {
            stream = new DataFileStream<GenericRecord>(in, datumReader);
            Schema schema = stream.getSchema();
            threw = false;
            return schema;
        } finally {
            Closeables.close(stream, threw);
        }
    }

    public static Schema fromAvro(File location) throws IOException {
        return fromAvro(FileSystem.getLocal(DefaultConfiguration.get()), new Path(location.getPath()));
    }

    public static Schema fromAvro(FileSystem fs, Path location) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = fs.open(location);
            Schema schema = fromAvro(in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    public static Schema fromAvro(Configuration conf, URI location) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = open(conf, location);
            Schema schema = fromAvro(in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    public static Schema fromParquet(File location) throws IOException {
        return fromParquet(FileSystem.getLocal(DefaultConfiguration.get()), new Path(location.getPath()));
    }

    public static Schema fromParquet(FileSystem fs, Path location) throws IOException {
        ParquetMetadata footer = ParquetFileReader.readFooter(fs.getConf(), location);

        String schemaString = footer.getFileMetaData().getKeyValueMetaData().get("parquet.avro.schema");
        if (schemaString == null) {
            // try the older property
            schemaString = footer.getFileMetaData().getKeyValueMetaData().get("avro.schema");
        }

        if (schemaString != null) {
            return new Schema.Parser().parse(schemaString);
        } else {
            return new AvroSchemaConverter().convert(footer.getFileMetaData().getSchema());
        }
    }

    public static Schema fromParquet(Configuration conf, URI location) throws IOException {
        Path path = new Path(location);
        return fromParquet(path.getFileSystem(conf), path);
    }

    public static Schema fromJSON(String name, InputStream in) throws IOException {
        return JsonUtil.inferSchema(in, name, 20);
    }

    public static Schema fromJSON(String name, File location) throws IOException {
        return fromJSON(name, FileSystem.getLocal(DefaultConfiguration.get()), new Path(location.getPath()));
    }

    public static Schema fromJSON(String name, FileSystem fs, Path location) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = fs.open(location);
            Schema schema = fromJSON(name, in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    public static Schema fromJSON(String name, Configuration conf, URI location) throws IOException {
        InputStream in = null;
        boolean threw = true;

        try {
            in = open(conf, location);
            Schema schema = fromJSON(name, in);
            threw = false;
            return schema;
        } finally {
            Closeables.close(in, threw);
        }
    }

    private static InputStream open(Configuration conf, URI location) throws IOException {
        if (RESOURCE_URI_SCHEME.equals(location.getScheme())) {
            return Resources.getResource(location.getRawSchemeSpecificPart()).openStream();
        } else {
            Path path = new Path(location);
            return path.getFileSystem(conf).open(path);
        }
    }

}