public abstract class StreamTableSink extends java.lang.Object implements TableSink
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.
Constructor and Description |
---|
StreamTableSink() |
Modifier and Type | Method and 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.
|
protected abstract void scanTable(StarTable table) throws java.io.IOException
StarTable.getRowSequence()
. Subsequent
getRowSequence
calls will result in a
UnrepeatableSequenceException
.
This method is called in a separate thread than the one in which
the accept*
calls are made; but any exceptions thrown
here are passed back to the latter thread.table
- table to consumejava.io.IOException
public void acceptMetadata(StarTable meta) throws TableFormatException
TableSink
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.
acceptMetadata
in interface TableSink
meta
- table metadata objectTableFormatException
- if this sink cannot accept table rows
matching the given metadatapublic void acceptRow(java.lang.Object[] row) throws java.io.IOException
TableSink