Class ColumnDataSpec

  • All Implemented Interfaces:
    DataSpec

    public class ColumnDataSpec
    extends AbstractDataSpec
    DataSpec implementation that simply selects columns by index from an input table. The mask is taken to be always true.
    Since:
    25 Sep 2013
    Author:
    Mark Taylor
    • Constructor Summary

      Constructors 
      Constructor Description
      ColumnDataSpec​(uk.ac.starlink.table.StarTable table, Coord[] coords, int[][] userCoordColIndices)
      Constructs a ColumnDataSpec with default mappers.
      ColumnDataSpec​(uk.ac.starlink.table.StarTable table, Coord[] coords, int[][] userCoordColIndices, uk.ac.starlink.table.DomainMapper[][] userCoordMappers)
      Constructs a ColumnDataSpec with supplied mappers.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      UserDataReader createUserDataReader()
      Returns an object that can be used to read the mask and coordinate values from a row sequence derived from this object's source table.
      Coord getCoord​(int ic)
      Returns the coord reader that can read the data for one of this object's output columns.
      int getCoordCount()
      Returns the number of columns that this object produces.
      java.lang.String getCoordId​(int ic)
      Returns an identifier for one of the the columns produced by this object.
      java.lang.String getMaskId()
      Returns an identifier for the row mask for this object.
      uk.ac.starlink.table.StarTable getSourceTable()
      Returns the table object from which this data spec's data is obtained.
      uk.ac.starlink.table.ValueInfo[] getUserCoordInfos​(int ic)
      Returns the metadata, if known, for the values supplied by the user to provide data for one of this object's output columns.
      uk.ac.starlink.table.DomainMapper[] getUserCoordMappers​(int ic)
      Returns the domain mappers to use for the values supplied by the user to provide data for one of this object's output columns.
      boolean isCoordBlank​(int icoord)
      Indicates whether the value for a given coord specified by this object is known to have a constant, blank value in all cases.
      boolean isMaskTrue()
      Returns true.
      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ColumnDataSpec

        public ColumnDataSpec​(uk.ac.starlink.table.StarTable table,
                              Coord[] coords,
                              int[][] userCoordColIndices)
        Constructs a ColumnDataSpec with default mappers.
        Parameters:
        table - input table
        coords - coordinate definitions for which columns are required
        userCoordColIndices - nCoord-element array, each element an array of column indices for the table columns containing user values for the corresponding Coord
      • ColumnDataSpec

        public ColumnDataSpec​(uk.ac.starlink.table.StarTable table,
                              Coord[] coords,
                              int[][] userCoordColIndices,
                              uk.ac.starlink.table.DomainMapper[][] userCoordMappers)
        Constructs a ColumnDataSpec with supplied mappers.
        Parameters:
        table - input table
        coords - coordinate definitions for which columns are required
        userCoordColIndices - nCoord-element array, each element an array of column indices for the table columns containing user values for the corresponding Coord
        userCoordMappers - nCoord-element array, each element an array of domain mappers for the table columns containing domain mappers for the corresponding Coord
    • Method Detail

      • getSourceTable

        public uk.ac.starlink.table.StarTable getSourceTable()
        Description copied from interface: DataSpec
        Returns the table object from which this data spec's data is obtained.
        Returns:
        data source table
      • getCoordCount

        public int getCoordCount()
        Description copied from interface: DataSpec
        Returns the number of columns that this object produces.
        Returns:
        TupleSequence column count
      • getCoordId

        public java.lang.String getCoordId​(int ic)
        Description copied from interface: DataSpec
        Returns an identifier for one of the the columns produced by this object. Coords with the same identifier must mean the same thing, and preferably vice versa.
        Parameters:
        ic - column index
        Returns:
        column identifier
      • getCoord

        public Coord getCoord​(int ic)
        Description copied from interface: DataSpec
        Returns the coord reader that can read the data for one of this object's output columns.
        Parameters:
        ic - column index
        Returns:
        column data reader
      • getMaskId

        public java.lang.String getMaskId()
        Description copied from interface: DataSpec
        Returns an identifier for the row mask for this object. Masks with the same identifier must mean the same thing, and preferably vice versa.
        Returns:
        mask identifier
      • getUserCoordInfos

        public uk.ac.starlink.table.ValueInfo[] getUserCoordInfos​(int ic)
        Description copied from interface: DataSpec
        Returns the metadata, if known, for the values supplied by the user to provide data for one of this object's output columns.
        Parameters:
        ic - column index
        Returns:
        array of value infos for column data inputs; elements may be null if not known
      • getUserCoordMappers

        public uk.ac.starlink.table.DomainMapper[] getUserCoordMappers​(int ic)
        Description copied from interface: DataSpec
        Returns the domain mappers to use for the values supplied by the user to provide data for one of this object's output columns. These objects define how the input values as supplied by the user are to be interpreted as the expected input values for this dataspec. In many cases this mapping is trivial (for instance Y axis coordinate), but in some (for instance absolute epoch) it may not be.
        Parameters:
        ic - column index
        Returns:
        array of DomainMappers for column data inputs
      • createUserDataReader

        public UserDataReader createUserDataReader()
        Description copied from interface: DataSpec
        Returns an object that can be used to read the mask and coordinate values from a row sequence derived from this object's source table. A given UserDataReader can only be used from a single thread, but multiple returns from this method may be used concurrently in different threads.
        Returns:
        new data reader
      • isMaskTrue

        public boolean isMaskTrue()
        Returns true.
        Returns:
        true if all rows are known to be included in the mask
      • isCoordBlank

        public boolean isCoordBlank​(int icoord)
        Description copied from interface: DataSpec
        Indicates whether the value for a given coord specified by this object is known to have a constant, blank value in all cases. Clients don't have to test this, since data stores will always dispense the relevant blank value based on this data spec, and should do so in an efficient manner, but it may be useful for clients to know in advance that a column is blank all the way down. False negatives are permitted: even if the result is false, the column may in fact have all blank values.
        Parameters:
        icoord - column index
        Returns:
        true if all values in the column are always blank