Package uk.ac.starlink.ttools.filter
Class SetParameterFilter
java.lang.Object
uk.ac.starlink.ttools.filter.BasicFilter
uk.ac.starlink.ttools.filter.SetParameterFilter
- All Implemented Interfaces:
ProcessingFilter
Filter which sets a parameter on the table.
- Since:
- 2 Aug 2006
- Author:
- Mark Taylor
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptioncreateStep
(Iterator<String> argIt) Creates a new ProcessingStep based on a sequence of command-line arguments.static Object
Evaluates an expression in the context of a table.protected String[]
Methods inherited from class uk.ac.starlink.ttools.filter.BasicFilter
explainSyntax, getDescription, getName, getUsage
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Constructor Details
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SetParameterFilter
public SetParameterFilter()
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Method Details
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getDescriptionLines
- Specified by:
getDescriptionLines
in classBasicFilter
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createStep
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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evaluate
public static Object evaluate(String expr, uk.ac.starlink.table.StarTable table, Class<?> clazz, String type) throws IOException Evaluates an expression in the context of a table. If a class is specified, the result is guaranteed to be of the type indicated by that class (or an error will be thrown). If no JEL expression can be evaluated, the supplied expression itself will be returned as a string, as long as that is not inconsistent with the requested class.- Parameters:
expr
- expression to evaluatetable
- evaluation contextclazz
- required class of result, or null; a primitive, rather than wrapper, class should be supplied if availabletype
- user-supplied string corresponding to clazz, or null (used for error messages only)- Throws:
IOException
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