Package uk.ac.starlink.ttools.filter
Class HeadFilter
- java.lang.Object
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- uk.ac.starlink.ttools.filter.BasicFilter
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- uk.ac.starlink.ttools.filter.HeadFilter
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- All Implemented Interfaces:
ProcessingFilter
public class HeadFilter extends BasicFilter
Filter for picking only the first few rows of a table.- Since:
- 7 Mar 2005
- Author:
- Mark Taylor (Starlink)
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Constructor Summary
Constructors Constructor Description HeadFilter()
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Method Summary
All Methods Instance Methods Concrete 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.protected java.lang.String[]
getDescriptionLines()
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Methods inherited from class uk.ac.starlink.ttools.filter.BasicFilter
explainSyntax, getDescription, getName, getUsage
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Method Detail
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getDescriptionLines
protected java.lang.String[] getDescriptionLines()
- Specified by:
getDescriptionLines
in classBasicFilter
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createStep
public ProcessingStep createStep(java.util.Iterator<java.lang.String> argIt) throws ArgException
Description copied from interface:ProcessingFilter
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
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