Package uk.ac.starlink.table
Class StreamTableSink
java.lang.Object
uk.ac.starlink.table.StreamTableSink
- All Implemented Interfaces:
TableSink
TableSink which turns its accepted data into a one-pass table and
does something with it (calls
scanTable(uk.ac.starlink.table.StarTable)
on it).
This effectively allows you to 'push' table data by writing it to this
TableSink rather than 'pulling' it by implementing a
RowSequence
; the latter may be a less
obvious or more fiddly way to work.
Note however this will only work for scanTable
implementations
which need only a single pass of the data.
See TableSink
for usage rules.
- Since:
- 8 Aug 2007
- Author:
- Mark Taylor
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
acceptMetadata
(StarTable meta) Takes delivery of a row-less StarTable 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.protected abstract void
Does something or other with the table whose data is being pushed into this sink.
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Constructor Details
-
StreamTableSink
public StreamTableSink()
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Method Details
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scanTable
Does something or other with the table whose data is being pushed into this sink. The only data access which will work is a single call toStarTable.getRowSequence()
. SubsequentgetRowSequence
calls will result in aUnrepeatableSequenceException
. This method is called in a separate thread than the one in which theaccept*
calls are made; but any exceptions thrown here are passed back to the latter thread.- Parameters:
table
- table to consume- Throws:
IOException
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acceptMetadata
Description copied from interface:TableSink
Takes delivery of a row-less StarTable object which defines the metadata of the table to be transmitted. If the number of rows that will be transmitted via subsequent calls to acceptRow is known, this value should be made available as the row count of meta (StarTable.getRowCount()
); if it is not known, the row count should be -1. However, this object should not attempt to read any of meta'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 to meta then it may throw a TableFormatException - this may be the case if for instance meta 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 of row 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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