Class ColumnStarTable

java.lang.Object
uk.ac.starlink.table.AbstractStarTable
uk.ac.starlink.table.RandomStarTable
uk.ac.starlink.table.ColumnStarTable
All Implemented Interfaces:
Closeable, AutoCloseable, StarTable
Direct Known Subclasses:
LoopStarTable
public abstract class ColumnStarTable extends RandomStarTable
A random-access StarTable that manages its data in columns. The data in each column is managed by a ColumnData object which can be accessed directly using the getColumnData(int) method. Columns can be added and substituted. If the columns permit it then table cells can be written to as well as read from.

Concrete subclasses of this abstract class must implement getRowCount(). If you just need a ColumnStarTable with a fixed number of rows you can use the static convenience method makeTableWithRows(long).

Author:
Mark Taylor (Starlink)

  • Field Details

  • Constructor Details

    • ColumnStarTable

      public ColumnStarTable()
      Default constructor.

    • ColumnStarTable

      public ColumnStarTable(StarTable template)
      Initialises a ColumnStarTable using a template StarTable to provide per-table metadata. The newly constructed object will have copies of the template's name, parameters etc.
      Parameters:
      template - the template StarTable

  • Method Details

    • getRowCount

      public abstract long getRowCount()
      Gets the number of rows in the table (which must be applicable to all the columns). Since this is a RandomStarTable the return value must be non-negative.
      Specified by:
      getRowCount in interface StarTable
      Specified by:
      getRowCount in class RandomStarTable
      Returns:
      number of rows

    • getColumnCount

      public int getColumnCount()
      Description copied from interface: StarTable
      Returns the number of columns in this table.
      Specified by:
      getColumnCount in interface StarTable
      Specified by:
      getColumnCount in class AbstractStarTable
      Returns:
      the number of columns

    • getColumnInfo

      public ColumnInfo getColumnInfo(int icol)
      Description copied from interface: StarTable
      Returns the object describing the data in a given column.
      Specified by:
      getColumnInfo in interface StarTable
      Specified by:
      getColumnInfo in class AbstractStarTable
      Parameters:
      icol - the column for which header information is required
      Returns:
      a ValueInfo object for column icol

    • getCell

      public Object getCell(long lrow, int icol) throws IOException
      Description copied from class: RandomStarTable
      Implementations of this method must be safe for concurrent calls from multiple threads.
      Specified by:
      getCell in interface StarTable
      Specified by:
      getCell in class RandomStarTable
      Parameters:
      lrow - the index of the cell's row
      icol - the index of the cell's column
      Returns:
      the contents of this cell
      Throws:
      IOException - if there is an error reading the data

    • setCell

      public void setCell(long lrow, int icol, Object value) throws IOException
      Stores an object in a given cell of the table.
      Parameters:
      lrow - the row index
      icol - the column index
      value - the value to store
      Throws:
      IOException - if an I/O error occurs
      UnsupportedOperationException - if column icol is not writable (!getColumnData(icol).isWritable());

    • getColumnData

      public ColumnData getColumnData(int icol)
      Returns the ColumnData object for a given column.
      Parameters:
      icol - the index of the column for which the result is required
      Returns:
      the ColumnData for column icol

    • addColumn

      public void addColumn(ColumnData coldata)
      Appends a new column to the end of this model.
      Parameters:
      coldata - the new column object to add

    • setColumn

      public void setColumn(int icol, ColumnData coldata)
      Substitutes a new column for the one which is currently in a given position. The old one is discarded.
      Parameters:
      icol - the column index to change
      coldata - the new column data object

    • makeTableWithRows

      public static ColumnStarTable makeTableWithRows(long nrow)
      Convenience method to return a ColumnStarTable with a fixed number of rows.
      Parameters:
      nrow - the number of rows this table will have

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