Class ConcatStarTable

java.lang.Object
uk.ac.starlink.table.WrapperStarTable
uk.ac.starlink.table.ConcatStarTable
All Implemented Interfaces:
Closeable, AutoCloseable, 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 Details

    • ConcatStarTable

      public ConcatStarTable(StarTable meta, 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 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:
      IOException - if any of tables are not compatible with meta
  • Method Details

    • 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 Object getCell(long irow, int icol) throws 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().

      This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.

      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:
      IOException - if there is an error reading the data
    • getRow

      public Object[] getRow(long irow) throws 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.

      This method is safe for concurrent use from multiple threads, but in general it is recommended to use a RowAccess instead.

      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:
      IOException - if there is an error reading the data
    • isRandom

      public boolean isRandom()
      Description copied from interface: StarTable
      Indicates whether random access is provided by this table. Only if the result is true may the StarTable.getRowAccess(), StarTable.getRow(long) and StarTable.getCell(long, int) methods be used.
      Specified by:
      isRandom in interface StarTable
      Overrides:
      isRandom in class WrapperStarTable
      Returns:
      true if table random access methods are available
    • 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
    • extendColumnTypes

      public static ColumnInfo[] extendColumnTypes(ColumnInfo[] colInfos, StarTable[] tables) throws 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:
      IOException - if compatibility cannot be achieved