SyntheticRowSubset (Starjava TOPCAT API)

java.lang.Object
- uk.ac.starlink.topcat.RowSubset
- - uk.ac.starlink.topcat.SyntheticRowSubset

```
public class SyntheticRowSubset
extends RowSubset
```
A RowSubset which uses an algebraic expression based on the values of other columns in the same row to decide whether a row is included or not.
The engine used for expression evaluation is the GNU Java Expressions Library (JEL).

Author:

Mark Taylor (Starlink)

See Also:

JEL

Field Summary
- Fields inherited from class uk.ac.starlink.topcat.RowSubset
  ALL, NONE

Constructor Summary

Constructors
Constructor	Description
`SyntheticRowSubset(java.lang.String name, java.lang.String expression, uk.ac.starlink.ttools.jel.RandomJELRowReader rowReader)`	Constructs a new synthetic subset given a table and an algebraic expression.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.lang.String`	`getExpression()`	Returns the text of the expression used by this subset.
`boolean`	`isIncluded(long lrow)`	Indicates whether a given row is in the subset or not.
`void`	`setExpression(java.lang.String expression, uk.ac.starlink.ttools.jel.RandomJELRowReader rowReader)`	Sets the expression to use for this subset.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from class uk.ac.starlink.topcat.RowSubset
getName, setName, toString

- Constructor Detail
  - SyntheticRowSubset
```
public SyntheticRowSubset(java.lang.String name,
                          java.lang.String expression,
                          uk.ac.starlink.ttools.jel.RandomJELRowReader rowReader)
                   throws gnu.jel.CompilationException
```
    Constructs a new synthetic subset given a table and an algebraic expression.
    
    Parameters:
    
    name - the name to use for the new RowSubset
    
    expression - the algebraic expression
    
    rowReader - context for JEL expression evaluation
    
    Throws:
    
    gnu.jel.CompilationException
- Method Detail
  - setExpression
```
public void setExpression(java.lang.String expression,
                          uk.ac.starlink.ttools.jel.RandomJELRowReader rowReader)
                   throws gnu.jel.CompilationException
```
    Sets the expression to use for this subset.
    
    Parameters:
    
    expression - JEL expression
    
    rowReader - context for JEL expression evaluation
    
    Throws:
    
    gnu.jel.CompilationException
  - getExpression
```
public java.lang.String getExpression()
```
    Returns the text of the expression used by this subset.
    
    Returns:
    
    expression
  - isIncluded
```
public boolean isIncluded(long lrow)
```
    Description copied from class: RowSubset
    
    Indicates whether a given row is in the subset or not.
    
    Specified by:
    
    isIncluded in class RowSubset
    
    Parameters:
    
    lrow - the index of the row in question
    
    Returns:
    
    true iff row lrow is to be included

Class SyntheticRowSubset

Field Summary

Fields inherited from class uk.ac.starlink.topcat.RowSubset

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from class uk.ac.starlink.topcat.RowSubset

Constructor Detail

SyntheticRowSubset

Method Detail

setExpression

getExpression

isIncluded