tech.tablesaw.io.DataFrameReader 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 tech.tablesaw.io;
import com.google.common.io.Files;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.Charset;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Optional;
import tech.tablesaw.api.Table;
import tech.tablesaw.io.csv.CsvReadOptions;
import tech.tablesaw.io.csv.CsvReader;
import tech.tablesaw.io.jdbc.SqlResultSetReader;
public class DataFrameReader {
private final ReaderRegistry registry;
public DataFrameReader(ReaderRegistry registry) {
this.registry = registry;
}
/**
* Reads the given URL into a table using default options Uses appropriate converter based on
* mime-type Use {@link #usingOptions(ReadOptions) usingOptions} to use non-default options
*/
public Table url(String url) {
try {
return url(new URL(url));
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}
/**
* Reads the given URL into a table using default options Uses appropriate converter based on
* mime-type Use {@link #usingOptions(ReadOptions) usingOptions} to use non-default options
*/
public Table url(URL url) {
URLConnection connection = null;
try {
connection = url.openConnection();
} catch (IOException e) {
e.printStackTrace();
}
String contentType = connection.getContentType();
return url(url, getCharset(contentType), getMimeType(contentType));
}
private Table url(URL url, Charset charset, String mimeType) {
Optional> reader = registry.getReaderForMimeType(mimeType);
if (reader.isPresent()) {
return readUrl(url, charset, reader.get());
}
reader = registry.getReaderForExtension(getExtension(url));
if (reader.isPresent()) {
return readUrl(url, charset, reader.get());
}
throw new IllegalArgumentException("No reader registered for mime-type " + mimeType);
}
private Table readUrl(URL url, Charset charset, DataReader reader) {
try {
return reader.read(new Source(url.openConnection().getInputStream(), charset));
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}
private String getMimeType(String contentType) {
String[] pair = contentType.split(";");
return pair[0].trim();
}
private Charset getCharset(String contentType) {
String[] pair = contentType.split(";");
return pair.length == 1
? Charset.defaultCharset()
: Charset.forName(pair[1].split("=")[1].trim());
}
/**
* Best effort method to get the extension from a URL.
*
* @param url the url to pull the extension from.
* @return the extension.
*/
private String getExtension(URL url) {
return Files.getFileExtension(url.getPath());
}
/**
* Reads the given string contents into a table using default options Uses converter specified
* based on given file extension Use {@link #usingOptions(ReadOptions) usingOptions} to use
* non-default options
*/
public Table string(String s, String fileExtension) {
Optional> reader = registry.getReaderForExtension(fileExtension);
if (!reader.isPresent()) {
throw new IllegalArgumentException("No reader registered for extension " + fileExtension);
}
return reader.get().read(Source.fromString(s));
}
/**
* Reads the given file into a table using default options Uses converter specified based on given
* file extension Use {@link #usingOptions(ReadOptions) usingOptions} to use non-default options
*/
public Table file(String file) {
return file(new File(file));
}
/**
* Reads the given file into a table using default options Uses converter specified based on given
* file extension Use {@link #usingOptions(ReadOptions) usingOptions} to use non-default options
*/
public Table file(File file) {
String extension = null;
try {
extension = Files.getFileExtension(file.getCanonicalPath());
Optional> reader = registry.getReaderForExtension(extension);
if (reader.isPresent()) {
return reader.get().read(new Source(file));
}
} catch (IOException e) {
throw new RuntimeIOException(e);
}
throw new IllegalArgumentException("No reader registered for extension " + extension);
}
public Table usingOptions(T options) {
DataReader reader = registry.getReaderForOptions(options);
return reader.read(options);
}
public Table usingOptions(ReadOptions.Builder builder) {
return usingOptions(builder.build());
}
public Table db(ResultSet resultSet) throws SQLException {
return SqlResultSetReader.read(resultSet);
}
public Table db(ResultSet resultSet, String tableName) throws SQLException {
Table table = SqlResultSetReader.read(resultSet);
table.setName(tableName);
return table;
}
// Legacy reader methods for backwards-compatibility
public Table csv(String file) {
return csv(CsvReadOptions.builder(file));
}
public Table csv(String contents, String tableName) {
try {
return csv(CsvReadOptions.builder(new StringReader(contents)).tableName(tableName));
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
public Table csv(File file) {
return csv(CsvReadOptions.builder(file));
}
public Table csv(InputStream stream) {
return csv(CsvReadOptions.builder(stream));
}
public Table csv(URL url) {
try {
return readUrl(url, getCharset(url.openConnection().getContentType()), new CsvReader());
} catch (IOException e) {
throw new RuntimeIOException(e);
}
}
public Table csv(InputStream stream, String name) {
return csv(CsvReadOptions.builder(stream).tableName(name));
}
public Table csv(Reader reader) {
return csv(CsvReadOptions.builder(reader));
}
public Table csv(CsvReadOptions.Builder options) {
return csv(options.build());
}
public Table csv(CsvReadOptions options) {
return new CsvReader().read(options);
}
}