uk.ac.starlink.ttools
Class JELSelectorTable
java.lang.Object
|
+--uk.ac.starlink.table.WrapperStarTable
|
+--uk.ac.starlink.ttools.JELSelectorTable
- All Implemented Interfaces:
- StarTable
- public class JELSelectorTable
- extends WrapperStarTable
Sequential table which selects rows on the basis of a JEL-interpreted
expression.
- See Also:
JELRowReader
Method Summary |
long |
getRowCount()
Returns the number of rows in this table, if known. |
RowSequence |
getRowSequence()
Returns an object which can iterate over all the rows in the table
sequentially. |
boolean |
isRandom()
Indicates whether random access is provided by this table. |
Methods inherited from class uk.ac.starlink.table.WrapperStarTable |
checkedLongToInt, getBaseTable, getCell, getColumnAuxDataInfos, getColumnCount, getColumnInfo, getName, getParameterByName, getParameters, getRow, getURL, setName, setParameter, setURL |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
JELSelectorTable
public JELSelectorTable(StarTable baseTable,
String expr)
throws gnu.jel.CompilationException
- Construct a table given a base table and a selection expression.
- Parameters:
baseTable
- base tableexpr
- boolean algebraic expression describing inclusion test
isRandom
public boolean isRandom()
- Description copied from interface:
StarTable
- Indicates whether random access is provided by this table.
Only if the result is true may the
StarTable.getRow(long)
and StarTable.getCell(long, int)
methods be used.
- Specified by:
isRandom
in interface StarTable
- Overrides:
isRandom
in class WrapperStarTable
- Returns:
- true if table random access methods are available
getRowCount
public long getRowCount()
- Description copied from interface:
StarTable
- Returns the number of rows in this table, if known. If the number
of rows cannot be (easily) determined, a value of -1 will be returned.
- Specified by:
getRowCount
in interface StarTable
- Overrides:
getRowCount
in class WrapperStarTable
- Returns:
- the number of rows, or -1
getRowSequence
public RowSequence getRowSequence()
throws IOException
- Description copied from interface:
StarTable
- Returns an object which can iterate over all the rows in the table
sequentially.
- Specified by:
getRowSequence
in interface StarTable
- Overrides:
getRowSequence
in class WrapperStarTable
- Returns:
- an object providing sequential access to the table data
- Throws:
IOException
- if there is an error providing access