Package uk.ac.starlink.table.storage
Class SidewaysRowStore
java.lang.Object
uk.ac.starlink.table.storage.SidewaysRowStore
RowStore implementation which stores data cell data in a column-oriented
fashion, so that members of the same column, rather than of the same row,
are stored contiguously on disk.
- Since:
- 21 Jun 2006
- Author:
- Mark Taylor
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Constructor Summary
ConstructorsConstructorDescriptionConstructs a new row store with an automatically chosen (and guaranteed unique) base pathname for scrach files.SidewaysRowStore
(File file) Constructs a new row store with a given base path name to use for temporary files. -
Method Summary
Modifier and TypeMethodDescriptionvoid
acceptMetadata
(StarTable meta) Takes delivery of a row-lessStarTable
object which defines the metadata of the table to be transmitted.void
Takes delivery of one row of data.void
endRows()
Signals that there are no more rows to be transmitted.Obtains a StarTable which contains the data and metadata that have been written into this sink.
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Constructor Details
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SidewaysRowStore
Constructs a new row store with a given base path name to use for temporary files.- Parameters:
file
- base scratch file name- Throws:
IOException
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SidewaysRowStore
Constructs a new row store with an automatically chosen (and guaranteed unique) base pathname for scrach files.- Throws:
IOException
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Method Details
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acceptMetadata
Description copied from interface:TableSink
Takes delivery of a row-lessStarTable
object which defines the metadata of the table to be transmitted. If the number of rows that will be transmitted via subsequent calls toacceptRow
is known, this value should be made available as the row count ofmeta
(StarTable.getRowCount()
); if it is not known, the row count should be -1. However, this object should not attempt to read any ofmeta
's cell data.The data to be transmitted in subsequent calls of
acceptRow
must match the metadata transmitted in this call in the same way that rows of a StarTable must match its own metadata (number and content clases of columns etc). If this sink cannot dispose of a table corresponding tometa
then it may throw a TableFormatException - this may be the case if for instancemeta
has columns with types that this sink can't deal with.- Specified by:
acceptMetadata
in interfaceTableSink
- Parameters:
meta
- table metadata object- Throws:
TableFormatException
- if this sink cannot accept table rows matching the given metadata
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acceptRow
Description copied from interface:TableSink
Takes delivery of one row of data.row
is an array of objects comprising the contents of one row of the table being transmitted. The number and classes of the elements ofrow
are described by the metadata object previously accepted.- Specified by:
acceptRow
in interfaceTableSink
- Parameters:
row
- table data row- Throws:
IOException
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endRows
Description copied from interface:TableSink
Signals that there are no more rows to be transmitted.- Specified by:
endRows
in interfaceTableSink
- Throws:
IOException
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getStarTable
Description copied from interface:RowStore
Obtains a StarTable which contains the data and metadata that have been written into this sink. In general it is only legal to call this method following a call toTableSink.endRows()
; failing to observe this sequence may earn you anIllegalStateException
- Specified by:
getStarTable
in interfaceRowStore
- Returns:
- a random-access StarTable containing the written rows
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