ProcessingFilter (Starjava TTOOLS API)

All Known Implementing Classes:

AddColumnFilter, AddSkyCoordsFilter, AssertFilter, BadValueFilter, BasicFilter, CacheFilter, CheckFilter, ClearParameterFilter, CollapseColsFilter, ColumnCalculatorFilter, ColumnMetadataFilter, DeleteColumnFilter, EveryFilter, ExplodeAllFilter, ExplodeColsFilter, FixNamesFilter, HeadFilter, HealpixMetadataFilter, 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

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`ProcessingStep`	`createStep(java.util.Iterator<java.lang.String> argIt)`	Creates a new ProcessingStep based on a sequence of command-line arguments.
`java.lang.String`	`getDescription()`	Description for this filter.
`java.lang.String`	`getUsage()`	Usage message for this filter.

- Method Detail
  - getUsage
```
java.lang.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
```
java.lang.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(java.util.Iterator<java.lang.String> 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.
    
    Parameters:
    
    argIt - iterator over command-line arguments positioned at the first one
    
    Throws:
    
    ArgException