Package uk.ac.starlink.table
Class StreamTableSink
- java.lang.Object
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- uk.ac.starlink.table.StreamTableSink
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- All Implemented Interfaces:
TableSink
public abstract class StreamTableSink extends java.lang.Object implements TableSink
TableSink which turns its accepted data into a one-pass table and does something with it (callsscanTable(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 aRowSequence
; the latter may be a less obvious or more fiddly way to work. Note however this will only work forscanTable
implementations which need only a single pass of the data.See
TableSink
for usage rules.- Since:
- 8 Aug 2007
- Author:
- Mark Taylor
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Constructor Summary
Constructors Constructor Description StreamTableSink()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
acceptMetadata(StarTable meta)
Takes delivery of a row-less StarTable object which defines the metadata of the table to be transmitted.void
acceptRow(java.lang.Object[] row)
Takes delivery of one row of data.void
endRows()
Signals that there are no more rows to be transmitted.protected abstract void
scanTable(StarTable table)
Does something or other with the table whose data is being pushed into this sink.
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Method Detail
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scanTable
protected abstract void scanTable(StarTable table) throws java.io.IOException
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:
java.io.IOException
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acceptMetadata
public void acceptMetadata(StarTable meta) throws TableFormatException
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
public void acceptRow(java.lang.Object[] row) throws java.io.IOException
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.
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