Class EmptyStarTable

java.lang.Object
uk.ac.starlink.table.WrapperStarTable
uk.ac.starlink.table.EmptyStarTable
All Implemented Interfaces:
Closeable, AutoCloseable, StarTable
public class EmptyStarTable extends WrapperStarTable
A wrapper table which has the same metadata as its base table, but no rows.
Since:
5 Aug 2004
Author:
Mark Taylor (Starlink)

  • Constructor Details

    • EmptyStarTable

      public EmptyStarTable(StarTable baseTable)
      Creates a new empty table with metadata taken from an existing one.
      Parameters:
      baseTable - base table

    • EmptyStarTable

      public EmptyStarTable()
      Creates a new empty table with no columns, no rows and no parameters.

  • Method Details

    • isRandom

      public boolean isRandom()
      Description copied from interface: StarTable
      Indicates whether random access is provided by this table. Only if the result is true may the StarTable.getRowAccess(), StarTable.getRow(long) and StarTable.getCell(long, int) methods be used.
      Specified by:
      isRandom in interface StarTable
      Overrides:
      isRandom in class WrapperStarTable
      Returns:
      true if table random access methods are available

    • getRowCount

      public long getRowCount()
      Description copied from interface: StarTable
      Returns the number of rows in this table, if known. If the number of rows cannot be (easily) determined, a value of -1 will be returned.
      Specified by:
      getRowCount in interface StarTable
      Overrides:
      getRowCount in class WrapperStarTable
      Returns:
      the number of rows, or -1

    • getCell

      public Object getCell(long lrow, int icol)
      Description copied from interface: StarTable
      Returns the contents of a given table cell. The class of the returned object should be the same as, or a subclass of, the class returned by getColumnInfo(icol).getContentClass().

      This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.

      Specified by:
      getCell in interface StarTable
      Overrides:
      getCell in class WrapperStarTable
      Parameters:
      lrow - the index of the cell's row
      icol - the index of the cell's column
      Returns:
      the contents of this cell

    • getRow

      public Object[] getRow(long lrow)
      Description copied from interface: StarTable
      Returns the contents of a given table row. The returned value is equivalent to an array formed of all the objects returned by getCell(irow,icol) for all the columns icol in sequence.

      This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.

      Specified by:
      getRow in interface StarTable
      Overrides:
      getRow in class WrapperStarTable
      Parameters:
      lrow - the index of the row to retrieve
      Returns:
      an array of the objects in each cell in row irow

    • getRowSequence

      public RowSequence getRowSequence()
      Description copied from interface: StarTable
      Returns an object which can iterate over all the rows in the table sequentially. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.
      Specified by:
      getRowSequence in interface StarTable
      Overrides:
      getRowSequence in class WrapperStarTable
      Returns:
      new RowSequence

    • getRowAccess

      public RowAccess getRowAccess()
      Description copied from interface: StarTable
      Returns an object which can provide random access to this table's data, if random access is implemented. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.
      Specified by:
      getRowAccess in interface StarTable
      Overrides:
      getRowAccess in class WrapperStarTable
      Returns:
      new RowAccess

    • getRowSplittable

      public RowSplittable getRowSplittable()
      Description copied from interface: StarTable
      Returns an object which can iterate over all the rows in the table, but which may also be requested to split recursively for potentially parallel processing.

      The return value must be non-null, and may provide splitting arrangements specially appropriate for the implementation. If this table 'wraps' an upstream table, it is usually best to base the implementation on calls to the the upstream getRowSplittable method, so that upstream policy about how to divide up the table is respected. However, implementations without special requirements may return Tables.getDefaultRowSplittable(this).

      Specified by:
      getRowSplittable in interface StarTable
      Overrides:
      getRowSplittable in class WrapperStarTable
      Returns:
      new RowSplittable
      See Also:

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