Package uk.ac.starlink.table

Class ConcatStarTable

  • All Implemented Interfaces:
    StarTable
    public class ConcatStarTable
extends WrapperStarTable
    StarTable implementation which concatenates several tables together top-to-bottom. A (possibly blank) metadata table is supplied to define the column and table metadata for the result, and other data tables are added on one way or another, depending which constructor is used. The columns of each data table must be compatible with the columns of the metadata table, or the the data will not be included.
    Since:
    29 Mar 2004
    Author:
    Mark Taylor

    • Constructor Detail

      • ConcatStarTable

        public ConcatStarTable​(StarTable meta,
                       java.util.Iterator<StarTable> tableIt)
        Constructs a concatenated table from a metadata table and an iterator over data-bearing tables. If any of the tables supplied by the iterator are incompatible with the metadata in meta a warning message is issued through the logging system and its rows are ignored.
        Parameters:
        meta - table supplying column and table metadata for this one; its row count is ignored and its data is never read
        tableIt - iterator over constituent StarTables which taken in sequence supply the row data for this one

      • ConcatStarTable

        public ConcatStarTable​(StarTable meta,
                       StarTable[] tables)
                throws java.io.IOException
        Constructs a concatenated table from a metadata table and an array of data-bearing tables. If any of tables are incompatible with the metadata in meta an IOException is thrown.
        Parameters:
        meta - table supplying column and table metadata for this one; its row count is ignored and its data is never read
        tables - array of tables which taken in sequence supply the row data for this one
        Throws:
        java.io.IOException - if any of tables are not compatible with meta

    • Method Detail

      • 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 java.lang.Object getCell​(long irow,
                                int icol)
                         throws java.io.IOException
        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().
        Specified by:
        getCell in interface StarTable
        Overrides:
        getCell in class WrapperStarTable
        Parameters:
        irow - the index of the cell's row
        icol - the index of the cell's column
        Returns:
        the contents of this cell
        Throws:
        java.io.IOException - if there is an error reading the data

      • getRow

        public java.lang.Object[] getRow​(long irow)
                          throws java.io.IOException
        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.
        Specified by:
        getRow in interface StarTable
        Overrides:
        getRow in class WrapperStarTable
        Parameters:
        irow - the index of the row to retrieve
        Returns:
        an array of the objects in each cell in row irow
        Throws:
        java.io.IOException - if there is an error reading the data

      • getRowSequence

        public RowSequence getRowSequence()
                           throws java.io.IOException
        Description copied from interface: StarTable
        Returns an object which can iterate over all the rows in the table sequentially.
        Specified by:
        getRowSequence in interface StarTable
        Overrides:
        getRowSequence in class WrapperStarTable
        Returns:
        an object providing sequential access to the table data
        Throws:
        java.io.IOException - if there is an error providing access

      • extendColumnTypes

        public static ColumnInfo[] extendColumnTypes​(ColumnInfo[] colInfos,
                                             StarTable[] tables)
                                      throws java.io.IOException
        Assembles column metadata objects which are compatible between multiple tables. Nullability, array shape and element size are set to values which can accommodate all of the input tables. If column count or column data types are inconsistent, an IOException is thrown.

        This utility method is not used by ConcatStarTable instances, but it may be useful when preparing metadata tables for use with the constructor.

        Parameters:
        colInfos - input column metadata objects
        tables - list of tables with which columns must be compatible
        Returns:
        new array of new column metadata objects, based on input list
        Throws:
        java.io.IOException - if compatibility cannot be achieved