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java.lang.Objectuk.ac.starlink.table.storage.DiskRowStore
Implementation of RowStore which stores data on disk. The temporary file is deleted by the finalizer (if it runs) or failing that at JVM exit. Since there's no guarantee when or if the finalizer will run even after this object is a candidate for garbage collection, this does raise the possibility that large numbers of potentially large temporary files will accumulate during JVM operation. It depends on your GC.
Constructor Summary | |
DiskRowStore()
Constructs a new DiskRowStore which uses a temporary file as backing store. |
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DiskRowStore(File file)
Constructs a new DiskRowStore which uses the given file as a backing store. |
Method Summary | |
void |
acceptMetadata(StarTable meta)
Takes delivery of a row-less StarTable object which defines the metadata of the table to be transmitted. |
void |
acceptRow(Object[] row)
Takes delivery of one row of data. |
void |
endRows()
Signals that there are no more rows to be transmitted. |
protected void |
finalize()
Finalizer deletes the temporary file used to cache the table data. |
StarTable |
getStarTable()
Obtains a StarTable which contains the data and metadata that have been written into this sink. |
Methods inherited from class java.lang.Object |
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public DiskRowStore(File file) throws IOException
file
- location of the backing file which will be used
IOException
- if there is some I/O-related problem with
opening the file
SecurityException
- if the current security context does not
allow writing to a temporary filepublic DiskRowStore() throws IOException
IOException
- if there is some I/O-related problem with
opening the file
SecurityException
- if the current security context does not
allow writing to a temporary fileMethod Detail |
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 object
TableFormatException
- if this sink cannot accept table rows
matching the given metadatapublic void acceptRow(Object[] row) throws IOException
TableSink
acceptRow
in interface TableSink
row
- table data row
IOException
public void endRows() throws IOException
TableSink
endRows
in interface TableSink
IOException
public StarTable getStarTable()
RowStore
TableSink.endRows()
; failing to observe this sequence may
earn you an IllegalStateException
getStarTable
in interface RowStore
protected void finalize() throws Throwable
Throwable
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Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved. | |||||||||
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