tech.bitey.dataframe

Enum DataFrameFactory

java.lang.Object

java.lang.Enum<DataFrameFactory>

tech.bitey.dataframe.DataFrameFactory

All Implemented Interfaces:

Serializable, Comparable<DataFrameFactory>

public enum DataFrameFactory
extends Enum<DataFrameFactory>

Factory methods for creating DataFrames.

Author:

biteytech@protonmail.com

Method Summary

Modifier and Type	Method and Description
static DataFrame	create(Column<?>[] columns, String[] columnNames) Returns a DataFrame with the specified columns and column names.
static DataFrame	create(Column<?>[] columns, String[] columnNames, String keyColumnName) Returns a DataFrame with the specified columns, column names, and key column name.
static DataFrame	create(LinkedHashMap<String,Column<?>> columnMap) Returns a DataFrame where the column names and columns are provided as ordered entries in columnMap.
static DataFrame	create(LinkedHashMap<String,Column<?>> columnMap, String keyColumnName) Returns a DataFrame where the column names and columns are provided as ordered entries in columnMap, and with the specified key column name.
static DataFrame	create(List<Column<?>> columns, List<String> columnNames) Returns a DataFrame with the specified columns and column names.
static DataFrame	create(List<Column<?>> columns, List<String> columnNames, String keyColumnName) Returns a DataFrame with the specified columns, column names, and key column name.
static DataFrame	readCsvFrom(File file, ReadCsvConfig config) Read a dataframe from a CSV file.
static DataFrame	readCsvFrom(InputStream is, ReadCsvConfig config) Read a dataframe in CSV format from the specified InputStream.
static DataFrame	readFrom(File file) Load a dataframe from a file created via DataFrame.writeTo(File).
static DataFrame	readFrom(ReadableByteChannel channel) Read a dataframe from the specified ReadableByteChannel.
static DataFrame	readFrom(ResultSet rs, ReadFromDbConfig config) Read a dataframe from the specified ResultSet according to the specified configuration.
static DataFrameFactory	valueOf(String name) Returns the enum constant of this type with the specified name.
static DataFrameFactory[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

values

public static DataFrameFactory[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DataFrameFactory c : DataFrameFactory.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DataFrameFactory valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

create

public static DataFrame create(LinkedHashMap<String,Column<?>> columnMap,
                               String keyColumnName)

Returns a DataFrame where the column names and columns are provided as ordered entries in columnMap, and with the specified key column name.

Parameters:

columnMap - - specifies the columns and column names

keyColumnName - - the key column name, must be present in as a key in columnMap. Can be null.

Returns:

a DataFrame where the column names and columns are provided as ordered entries in columnMap.

Throws:

IllegalArgumentException - if:

• columnMap is empty
• columnMap contains any null keys or values
• all columns do not have the same size
• keyColumnName is not null and is either not present as a key in columnMap, or refers to a column which is not a unique index

create

public static DataFrame create(LinkedHashMap<String,Column<?>> columnMap)

Returns a DataFrame where the column names and columns are provided as ordered entries in columnMap.

Parameters:

columnMap - - specifies the columns and column names

Returns:

a DataFrame where the column names and columns are provided as ordered entries in columnMap.

Throws:

IllegalArgumentException - if:

• columnMap is empty
• columnMap contains any null keys or values
• all columns do not have the same size

create

public static DataFrame create(Column<?>[] columns,
                               String[] columnNames,
                               String keyColumnName)

Returns a DataFrame with the specified columns, column names, and key column name.

Parameters:

columns - - the columns

columnNames - - the column names

keyColumnName - - the key column name, must be present in columnNames. Can be null.

Returns:

a DataFrame with the specified columns and column names.

Throws:

IllegalArgumentException - if:

• column names are not distinct
• mismatched number of columns vs. column names
• zero columns provided
• all columns do not have the same size
• keyColumnName is not null and is either not present in columnNames, or refers to a column which is not a unique index

create

public static DataFrame create(Column<?>[] columns,
                               String[] columnNames)

Returns a DataFrame with the specified columns and column names.

Parameters:

columns - - the columns

columnNames - - the column names

Returns:

a DataFrame with the specified columns and column names.

Throws:

IllegalArgumentException - if:

• column names are not distinct
• mismatched number of columns vs. column names
• zero columns provided
• all columns do not have the same size

create

public static DataFrame create(List<Column<?>> columns,
                               List<String> columnNames,
                               String keyColumnName)

Returns a DataFrame with the specified columns, column names, and key column name.

Parameters:

columns - - the columns

columnNames - - the column names

keyColumnName - - the key column name, must be present in columnNames. Can be null.

Returns:

a DataFrame with the specified columns and column names.

Throws:

IllegalArgumentException - if:

• column names are not distinct
• mismatched number of columns vs. column names
• zero columns provided
• all columns do not have the same size
• keyColumnName is not null and is either not present in columnNames, or refers to a column which is not a unique index

create

public static DataFrame create(List<Column<?>> columns,
                               List<String> columnNames)

Returns a DataFrame with the specified columns and column names.

Parameters:

columns - - the columns

columnNames - - the column names

Returns:

a DataFrame with the specified columns and column names.

Throws:

IllegalArgumentException - if:

• column names are not distinct
• mismatched number of columns vs. column names
• zero columns provided
• all columns do not have the same size

readFrom

public static DataFrame readFrom(File file)
                          throws IOException

Load a dataframe from a file created via DataFrame.writeTo(File).

Parameters:

file - - the file to read from

Returns:

the dataframe loaded from the specified file

Throws:

IOException - if some I/O error occurs

readFrom

public static DataFrame readFrom(ReadableByteChannel channel)
                          throws IOException

Read a dataframe from the specified ReadableByteChannel.

Parameters:

channel - - the channel to read from

Returns:

the dataframe read from the specified channel

Throws:

IOException - if some I/O error occurs

readCsvFrom

public static DataFrame readCsvFrom(File file,
                                    ReadCsvConfig config)
                             throws IOException

Read a dataframe from a CSV file. The CSV must adhere to RFC 4180, with the following exceptions:

• Lines can end in CR, LF, or CRLF (not just CRLF as defined in the RFC)
• If a CR or CRLF appears within a field, it will be converted to LF
• A delimiter other than comma may be specified in the configuration
• A header line must be present if and only if the column names are not provided in the configuration

Parameters:

file - - the file containing the CVS data

config - - configuration for parsing the CSV file. See ReadCsvConfig.

Returns:

the dataframe read from the CSV file

Throws:

IOException - if some I/O error occurs

RuntimeException - if there is any other error parsing the CVS file

See Also:

ReadCsvConfig

readCsvFrom

public static DataFrame readCsvFrom(InputStream is,
                                    ReadCsvConfig config)
                             throws IOException

Read a dataframe in CSV format from the specified InputStream. The CSV must adhere to RFC 4180, with the following exceptions:

• Lines can end in CR, LF, or CRLF (not just CRLF as defined in the RFC)
• If a CR or CRLF appears within a field, it will be converted to LF
• A delimiter other than comma may be specified in the configuration
• A header line must be present if and only if the column names are not provided in the configuration

Parameters:

is - - the InputStream containing the CSV data

config - - configuration for parsing the CSV file. See ReadCsvConfig.

Returns:

the dataframe read from the CSV file

Throws:

IOException - if some I/O error occurs

RuntimeException - if there is any other error parsing the CVS file

See Also:

ReadCsvConfig

readFrom

public static DataFrame readFrom(ResultSet rs,
                                 ReadFromDbConfig config)
                          throws SQLException

Read a dataframe from the specified ResultSet according to the specified configuration.

Parameters:

rs - - a ResultSet

config - - a configuration containing per-column logic for getting fields from the ResultSet. The number of columns in the configuration must match the number in the ResultSet. Configurations can be reused for multiple ResultSets.

Returns:

the dataframe read from the ResultSet

Throws:

SQLException - if some SQL or database error occurs

IllegalStateException - if the number of columns in the configuration does not match the number in the ResultSet