Class WrapperRowAccess

java.lang.Object
uk.ac.starlink.table.WrapperRowAccess
All Implemented Interfaces:
Closeable, AutoCloseable, RowAccess, RowData

public class WrapperRowAccess extends Object implements RowAccess
RowAccess which wraps another RowAccess. This class acts as a wrapper around an existing 'base' RowSequence object; all its methods are implemented by forwarding them to the corresponding methods of that base sequence.

This class is provided so that it can be extended by subclasses which modify the view of the base sequence in useful ways.

Since:
24 Jul 2020
Author:
Mark Taylor (Starlink)
See Also:
  • Constructor Details

    • WrapperRowAccess

      public WrapperRowAccess(RowAccess baseAcc)
      Constructs a new RowAccess based on a given one.
      Parameters:
      baseAcc - the base row access
    • WrapperRowAccess

      public WrapperRowAccess(RowAccess baseAcc, RowData data)
      Constructs a new RowAccess based on a given one but with a supplied data access implementation.
      Parameters:
      baseAcc - the base row access
      data - RowData object whose methods will be used to implement the getCell and getRow methods
  • Method Details

    • setRowIndex

      public void setRowIndex(long irow) throws IOException
      Description copied from interface: RowAccess
      Sets the row index to which subsequent data accesses will refer.

      This method must be called before the first invocation of RowAccess.getCell(int)/RowAccess.getRow(), otherwise behaviour is undefined (but implementations will likely throw an unchecked exception on subsequent getCell/getRow calls). The effect of setting the value to an out of range value is undefined; it may throw an exception here, or during subsequent calls, or behave otherwise.

      Specified by:
      setRowIndex in interface RowAccess
      Parameters:
      irow - row index
      Throws:
      IOException
    • getCell

      public Object getCell(int icol) throws IOException
      Description copied from interface: RowAccess
      Returns the contents of a given cell at the current row.

      Behaviour is undefined if the row index has not been set, or has been set to a value for which no table row exists; however implementations are encouraged to throw suitable RuntimeException in this case.

      Specified by:
      getCell in interface RowAccess
      Specified by:
      getCell in interface RowData
      Parameters:
      icol - column index
      Returns:
      contents of given column at current row
      Throws:
      IOException - if there's a problem reading the value
    • getRow

      public Object[] getRow() throws IOException
      Description copied from interface: RowAccess
      Returns the contents of all the cells at the current row.

      Note the returned object may be reused between invocations,

      Behaviour is undefined if the row index has not been set, or has been set to a value for which no table row exists; however implementations are encouraged to throw a suitable RuntimeException in this case.

      Specified by:
      getRow in interface RowAccess
      Specified by:
      getRow in interface RowData
      Returns:
      array with one element for each column in the table
      Throws:
      IOException
    • close

      public void close() throws IOException
      Description copied from interface: RowAccess
      Closes this reader. 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 RowAccess
      Throws:
      IOException
    • toString

      public String toString()
      Returns an indication of the wrapper structure of this object.
      Overrides:
      toString in class Object
      Returns:
      string representation