Class ReaderRowSequence

java.lang.Object
uk.ac.starlink.table.ReaderRowSequence
All Implemented Interfaces:
Closeable, AutoCloseable, RowData, RowSequence, uk.ac.starlink.util.Sequence
public abstract class ReaderRowSequence extends Object implements RowSequence
Partial implementation of RowSequence suitable for subclassing by classes which can read a row at a time and don't know when the row stream will come to an end. Concrete subclasses have to implement the readRow() method. They may also want to override close().
Author:
Mark Taylor (Starlink)

  • Constructor Summary

    Constructors
    Constructor
    Description
    ReaderRowSequence()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    The ReaderRowSequence implementation does nothing.
    Object
    getCell(int icol)
    Returns the contents of a cell in the current row.
    Object[]
    getRow()
    Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table.
    boolean
    next()
    Attempts to advance the current row to the next one.
    protected abstract Object[]
    readRow()
    Acquires the next row of objects from the input stream.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • ReaderRowSequence

      public ReaderRowSequence()

  • Method Details

    • readRow

      protected abstract Object[] readRow() throws IOException
      Acquires the next row of objects from the input stream. When there are no more rows to read this method must return null; note it should not throw an exception to indicate this fact. Otherwise it must return an array of objects representing the row content for the next row.
      Returns:
      the next row, or null if there are no more
      Throws:
      IOException - if there is trouble reading the data

    • 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)
      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

    • getRow

      public Object[] getRow()
      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

    • close

      public void close() throws IOException
      The ReaderRowSequence implementation does nothing.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface RowSequence
      Throws:
      IOException

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