Class RowPermutedStarTable
- All Implemented Interfaces:
Closeable
,AutoCloseable
,StarTable
A long[]
array, rowMap
, is used to keep
track of which rows in this table correspond to which rows in the
base table; the n
'th row in this table corresponds to the
rowMap[n]
'th row in the base table.
The rowMap
array may contain duplicate entries, but should
not contain any entries larger than the number of rows in the base table.
Any negative entry is treated as a special case resulting in a 'blank'
row of all null values.
It can be modified during the life of the table, but it's not a good
idea to do this while a RowSequence
is active.
- Author:
- Mark Taylor (Starlink)
-
Field Summary
Fields inherited from class uk.ac.starlink.table.WrapperStarTable
baseTable
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Constructor Summary
ConstructorsConstructorDescriptionRowPermutedStarTable
(StarTable baseTable) Constructs a new RowPermutedTable with rows initially in unpermuted order.RowPermutedStarTable
(StarTable baseTable, long[] rowMap) Constructs a newRowPermutedStarTable
from a base table and arowMap
array. -
Method Summary
Modifier and TypeMethodDescriptiongetCell
(long irow, int icol) Returns the contents of a given table cell.Object[]
getRow
(long irow) Returns the contents of a given table row.Returns an object which can provide random access to this table's data, if random access is implemented.long
Returns the number of rows in this table, if known.long[]
Returns the mapping array.Returns an object which can iterate over all the rows in the table sequentially.Returns an object which can iterate over all the rows in the table, but which may also be requested to split recursively for potentially parallel processing.boolean
isRandom()
Returns true.void
setRowMap
(long[] rowMap) Sets the mapping array.Methods inherited from class uk.ac.starlink.table.WrapperStarTable
checkedLongToInt, close, getBaseTable, getColumnAuxDataInfos, getColumnCount, getColumnInfo, getName, getParameterByName, getParameters, getURL, setName, setParameter, setURL, toString
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Constructor Details
-
RowPermutedStarTable
Constructs a newRowPermutedStarTable
from a base table and arowMap
array.baseTable
must provide random access.- Parameters:
baseTable
- base tablerowMap
- array mapping rows in the new permuted table to rows inbaseTable
- Throws:
IllegalArgumentException
- ifbaseTable.isRandom
returnsfalse
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RowPermutedStarTable
Constructs a new RowPermutedTable with rows initially in unpermuted order.- Parameters:
baseTable
- base table
-
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Method Details
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getRowMap
public long[] getRowMap()Returns the mapping array.- Returns:
- array mapping rows in this table to rows in the base table
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setRowMap
public void setRowMap(long[] rowMap) Sets the mapping array.- Parameters:
rowMap
- array mapping rows in this table to rows in the base table
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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 interfaceStarTable
- Overrides:
getRowCount
in classWrapperStarTable
- Returns:
- the number of rows, or -1
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isRandom
public boolean isRandom()Returns true.- Specified by:
isRandom
in interfaceStarTable
- Overrides:
isRandom
in classWrapperStarTable
- Returns:
true
if table random access methods are available
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getRowAccess
Description copied from interface:StarTable
Returns an object which can provide random access to this table's data, if random access is implemented. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.- Specified by:
getRowAccess
in interfaceStarTable
- Overrides:
getRowAccess
in classWrapperStarTable
- Returns:
- new RowAccess
- Throws:
IOException
- if there is an error setting up access
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getRowSequence
Description copied from interface:StarTable
Returns an object which can iterate over all the rows in the table sequentially. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.- Specified by:
getRowSequence
in interfaceStarTable
- Overrides:
getRowSequence
in classWrapperStarTable
- Returns:
- new RowSequence
- Throws:
IOException
- if there is an error providing access
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getRowSplittable
Description copied from interface:StarTable
Returns an object which can iterate over all the rows in the table, but which may also be requested to split recursively for potentially parallel processing.The return value must be non-null, and may provide splitting arrangements specially appropriate for the implementation. If this table 'wraps' an upstream table, it is usually best to base the implementation on calls to the the upstream
getRowSplittable
method, so that upstream policy about how to divide up the table is respected. However, implementations without special requirements may returnTables.getDefaultRowSplittable
(this)
.- Specified by:
getRowSplittable
in interfaceStarTable
- Overrides:
getRowSplittable
in classWrapperStarTable
- Returns:
- new RowSplittable
- Throws:
IOException
- See Also:
-
getCell
Description copied from interface:StarTable
Returns the contents of a given table cell. The class of the returned object should be the same as, or a subclass of, the class returned bygetColumnInfo(icol).getContentClass()
.This method is safe for concurrent use from multiple threads, but in general it is recommended to use a
RowAccess
instead.- Specified by:
getCell
in interfaceStarTable
- Overrides:
getCell
in classWrapperStarTable
- Parameters:
irow
- the index of the cell's rowicol
- the index of the cell's column- Returns:
- the contents of this cell
- Throws:
IOException
- if there is an error reading the data
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getRow
Description copied from interface:StarTable
Returns the contents of a given table row. The returned value is equivalent to an array formed of all the objects returned bygetCell(irow,icol)
for all the columnsicol
in sequence.This method is safe for concurrent use from multiple threads, but in general it is recommended to use a
RowAccess
instead.- Specified by:
getRow
in interfaceStarTable
- Overrides:
getRow
in classWrapperStarTable
- Parameters:
irow
- the index of the row to retrieve- Returns:
- an array of the objects in each cell in row
irow
- Throws:
IOException
- if there is an error reading the data
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