Module datarush.library
Package com.pervasive.datarush.operators.io.textfile

Class ARFFDataFormat

  • All Implemented Interfaces:
    DataFormat
    public class ARFFDataFormat
extends Object
implements DataFormat
    Describes an instance of ARFF data. Normally, it is not necessary construct these directly. Instead, use ReadARFF and WriteARFF to access data stored as ARRF.

    • Constructor Detail

      • ARFFDataFormat

        public ARFFDataFormat​(ARFFMode mode,
                      TextRecord schema,
                      CharsetEncoding encoding,
                      String recordSeparator,
                      char fieldDelimiter,
                      String relationName,
                      List<String> comments)
        Create an ARFF data format for writing to an ARFF file.
        Parameters:
        mode - indicates the mode for representing record data
        schema - the schema to use for records. This provides field names (and positions) as well as the formatting of field values.
        encoding - character set definition for data encoding
        recordSeparator - characters to use as a separator between records
        fieldDelimiter - the character use to delimit field values when the value contains spaces
        relationName - name of the relation
        comments - comments to associate with data written using this format.

      • ARFFDataFormat

        public ARFFDataFormat​(ARFFMode mode,
                      TextRecord schema,
                      CharsetEncoding encoding,
                      char fieldDelimiter)
        Create an ARFF data format for reading an ARFF file.
        Parameters:
        mode - indicates the mode for representing record data
        schema - the schema to use for records. This provides field names (and positions) as well as the formatting of field values. This schema also controls the output type of the reader.
        encoding - character set definition for data encoding
        fieldDelimiter - the character use to delimit field values when the value contains spaces

    • Method Detail

      • getType

        public RecordTokenType getType()
        Description copied from interface: DataFormat
        Gets the record type associated with the format. Records produced by the associated parser or consumed by the associated formatter will be of this type.

        For many formats, this may be derived from a schema object describing the format layout.

        Specified by:
        getType in interface DataFormat
        Returns:
        the format's record type

      • getMetadata

        public FileMetadata getMetadata()
        Description copied from interface: DataFormat
        Gets the metadata associated with the format. Records produces by the associated parser or consumed by the associated formatter will use this metadata.
        Specified by:
        getMetadata in interface DataFormat
        Returns:
        the format's metadata

      • readMetadata

        public FileMetadata readMetadata​(FileClient fileClient,
                                 ByteSource source)
        Description copied from interface: DataFormat
        Reads the metadata associated with the format.
        Specified by:
        readMetadata in interface DataFormat
        Parameters:
        fileClient - client used to read file
        source - location of the files

      • writeMetadata

        public void writeMetadata​(FileMetadata metadata,
                          FileClient fileClient,
                          ByteSink target)
        Description copied from interface: DataFormat
        Writes the provided metadata associated with the format.
        Specified by:
        writeMetadata in interface DataFormat
        Parameters:
        metadata - the metadata to write
        fileClient - client used to write file

      • createParser

        public DataFormat.DataParser createParser​(ParsingOptions options)
        Description copied from interface: DataFormat
        Create a new parser for the format using the specified parsing options.
        Specified by:
        createParser in interface DataFormat
        Parameters:
        options - parsing options to use
        Returns:
        a new parser for reading external data

      • createWriter

        public DataFormat.DataFormatter createWriter​(FormattingOptions options)
        Description copied from interface: DataFormat
        Create a new writer for the format using the specified formatting options.
        Specified by:
        createWriter in interface DataFormat
        Parameters:
        options - formatting options to use
        Returns:
        a new formatter for writing external data

      • isSplittable

        public boolean isSplittable()
        Indicates if the format supports parsing of subsections of a file.

        A format should only return true if it can, at least in some situations, support this sort of parsing. If a format requires reading the entire file, it must return false.

        If a format is not splittable, a file in the format cannot be parsed in parallel; however, individual files can still be parsed independently in parallel, as when reading the contents of a directory or using a file globbing pattern.

        ARFF is a splittable format.

        Specified by:
        isSplittable in interface DataFormat
        Returns:
        true if the format supports parsing only a portion of the file, false otherwise