Package uk.ac.starlink.table

Class RandomRowSplittable

java.lang.Object
uk.ac.starlink.table.RandomRowSplittable
All Implemented Interfaces:
Closeable, AutoCloseable, RowData, RowSequence, RowSplittable, uk.ac.starlink.util.Sequence, uk.ac.starlink.util.Splittable<RowSplittable>
public class RandomRowSplittable extends Object implements RowSplittable
RowSplittable based on a RowAccess.
Since:
4 Aug 2020
Author:
Mark Taylor

  • Constructor Details

  • Method Details

    • splittableSize

      public long splittableSize()
      Specified by:
      splittableSize in interface uk.ac.starlink.util.Splittable<RowSplittable>

    • split

      public RandomRowSplittable split()
      Specified by:
      split in interface uk.ac.starlink.util.Splittable<RowSplittable>

    • rowIndex

      public LongSupplier rowIndex()
      Description copied from interface: RowSplittable
      Returns a supplier for the index of the row currently being processed, if possible. The row index is a global value; when accessing the first row of a top-level RowSplittable, the value returned by this supplier should be the first index in the table. But for objects resulting from splitting a top-level instance into sub-instances, the return value should reflect the index in the original sequence of rows; each index should be returned from only one of the splittables resulting from splitting a top-level instance.

      Typically, the row index will start at 0 and increment for each row, but the numbering may be different depending on the requirements of the implementation or usage.

      Before the RowSequence.next() method has been called, the return value will be one less than the first row index. After RowSequence.next has returned false, the value is undefined.

      Depending on the implementation, it may not be possible to determine the row index (for instance if the sequence is split into sub-splittables of unknown size). In such cases, this method returns null. The null-ness of the return value must be the same for all instances of the splittable hierarchy for a given sequence, so don't return a non-null value for the first splittable and then null values for some or all of its children.

      Specified by:
      rowIndex in interface RowSplittable
      Returns:
      supplier for the globally-referenced row index value of the current row of this sequence, or null

    • next

      public boolean next() throws IOException
      Description copied from interface: RowSequence
      Attempts to advance the current row to the next one. If true is returned the attempt has been successful, and if false is returned there are no more rows in this sequence. Since the initial position of a RowSequence is before the first row, this method must be called before current row data can be accessed using the RowSequence.getCell(int) or RowSequence.getRow() methods.
      Specified by:
      next in interface RowSequence
      Specified by:
      next in interface uk.ac.starlink.util.Sequence
      Returns:
      true iff this sequence has been advanced to the next row
      Throws:
      IOException - if there is some error

    • getCell

      public Object getCell(int icol) throws IOException
      Description copied from interface: RowSequence
      Returns the contents of a cell in the current row. The class of the returned object should be the same as, or a subclass of, the class returned by getColumnInfo(icol).getContentClass(). An unchecked exception will be thrown if there is no current row (next has not yet been called).
      Specified by:
      getCell in interface RowData
      Specified by:
      getCell in interface RowSequence
      Parameters:
      icol - column index
      Returns:
      the contents of cell icol in the current row
      Throws:
      IOException - if there is an error reading the data

    • getRow

      public Object[] getRow() throws IOException
      Description copied from interface: RowSequence
      Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table. An unchecked exception will be thrown if there is no current row (next has not yet been called).
      Specified by:
      getRow in interface RowData
      Specified by:
      getRow in interface RowSequence
      Returns:
      an array of the objects in each cell in row irow
      Throws:
      IOException - if there is an error reading the data

    • close

      public void close() throws IOException
      Description copied from interface: RowSequence
      Indicates that this sequence will not be required any more. This should release resources associated with this object. The effect of calling any of the other methods following a close is undefined.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface RowSequence
      Throws:
      IOException