uk.ac.starlink.ttools.filter
Interface ProcessingFilter

All Known Implementing Classes:
AddColumnFilter, AddSkyCoordsFilter, AssertFilter, BadValueFilter, BasicFilter, CacheFilter, CheckFilter, ClearParameterFilter, ColumnCalculatorFilter, ColumnMetadataFilter, DeleteColumnFilter, EveryFilter, ExplodeAllFilter, ExplodeColsFilter, FixNamesFilter, HeadFilter, KeepColumnFilter, MetadataFilter, NameFilter, PixSampleFilter, ProgressFilter, RandomFilter, RandomViewFilter, RangeFilter, RepeatFilter, ReplaceColumnFilter, ReplaceValueFilter, ResolverFilter, SchlegelFilter, SelectFilter, SequentialViewFilter, SetParameterFilter, SortFilter, SortHeadFilter, StatsFilter, TailFilter, TransposeFilter, UniqueFilter

public interface ProcessingFilter

Defines a type of filter-like processing which can be done on a StarTable. An object in this class serves as a factory for ProcessingStep instances, based on a list of command-line arguments.

Since:
3 Mar 2005
Author:
Mark Taylor (Starlink)

Method Summary
 ProcessingStep createStep(Iterator argIt)
          Creates a new ProcessingStep based on a sequence of command-line arguments.
 String getDescription()
          Description for this filter.
 String getUsage()
          Usage message for this filter.
 

Method Detail

getUsage

String getUsage()
Usage message for this filter. This should contain any arguments which apply to this item; the name itself should not be included. May contain newline characters to break up a long line.

Returns:
usage string

getDescription

String getDescription()
Description for this filter. This is currently inserted into the user document, so should be in XML format.

Returns:
textual description of this filter

createStep

ProcessingStep createStep(Iterator argIt)
                          throws ArgException
Creates a new ProcessingStep based on a sequence of command-line arguments. The argIt argument is an iterator over the command-line arguments positioned just before any arguments intended for this filter. If legal, any that can be comprehended by this filter should be read (iterated over) and removed, and a ProcessingStep should accordingly be returned. In the case of a successful return, it is essential that no arguments other than the ones intended for this filter are read from the iterator.

If the argument list is badly-formed as far as this filter is concerned, an ArgException should be thrown. If its usageFrament is blank, it will be filled in later using this mode's usage text.

Parameters:
argIt - iterator over command-line arguments positioned at the first one
Throws:
ArgException


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