Package uk.ac.starlink.table

Class SelectorStarTable

java.lang.Object
uk.ac.starlink.table.WrapperStarTable
uk.ac.starlink.table.SelectorStarTable
All Implemented Interfaces:
Closeable, AutoCloseable, StarTable
public abstract class SelectorStarTable extends WrapperStarTable
Sequential wrapper table which selects only certain rows of its base table. No random access is provided, and the row sequence evaluates the abstract isIncluded(uk.ac.starlink.table.RowSequence) method for each row of the base table as it is iterated over.
Since:
11 Feb 2005
Author:
Mark Taylor (Starlink)

  • Constructor Details

    • SelectorStarTable

      public SelectorStarTable(StarTable baseTable)
      Constructor.
      Parameters:
      baseTable - table on which this is based

  • Method Details

    • isIncluded

      public abstract boolean isIncluded(RowSequence baseSeq) throws IOException
      Evaluated to determine whether rows of the base table are included in this one.
      Parameters:
      baseSeq - row sequence of the base table
      Returns:
      true iff the current row of baseSeq is to be included
      Throws:
      IOException

    • isRandom

      public boolean isRandom()
      Returns false.
      Specified by:
      isRandom in interface StarTable
      Overrides:
      isRandom in class WrapperStarTable
      Returns:
      true if table random access methods are available

    • getRowCount

      public long getRowCount()
      Returns -1 (length unknown).
      Specified by:
      getRowCount in interface StarTable
      Overrides:
      getRowCount in class WrapperStarTable
      Returns:
      the number of rows, or -1

    • getRow

      public Object[] getRow()

    • getCell

      public Object getCell(int icol)

    • getRowSequence

      public RowSequence getRowSequence() throws IOException
      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
      Throws:
      IOException - if there is an error providing access

    • getRowSplittable

      public RowSplittable getRowSplittable() throws IOException
      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
      Throws:
      IOException
      See Also:

    • 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