uk.ac.starlink.table.formats
Class CoinsTableBuilder

java.lang.Object
  extended by uk.ac.starlink.table.formats.CoinsTableBuilder
All Implemented Interfaces:
TableBuilder

public class CoinsTableBuilder
extends java.lang.Object
implements TableBuilder

Can be used to make sense of the COINS data from the UK Government. It is CSV-like, but has '@' characters as the separators. Tested on file /fact_table_extract_2009_10.zip from http://data.gov.uk/. Clearly, this is of limited use for astronomical analysis, but it may provide a template for implementation of other custom CSV-like data sets.

Since:
30 Jun 2010

Constructor Summary
CoinsTableBuilder()
           
 
Method Summary
 boolean canImport(java.awt.datatransfer.DataFlavor flavor)
          Indicates whether this builder is able to turn a resource of media type indicated by flavor into a table.
 java.lang.String getFormatName()
          Returns "COINS".
 StarTable makeStarTable(DataSource datsrc, boolean wantRandom, StoragePolicy policy)
          Constructs a StarTable based on a given DataSource.
 void streamStarTable(java.io.InputStream in, TableSink sink, java.lang.String pos)
          Reads a table from an input stream and writes it a row at a time to a sink.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CoinsTableBuilder

public CoinsTableBuilder()
Method Detail

getFormatName

public java.lang.String getFormatName()
Returns "COINS".

Specified by:
getFormatName in interface TableBuilder
Returns:
one-word description of this handler's format

canImport

public boolean canImport(java.awt.datatransfer.DataFlavor flavor)
Description copied from interface: TableBuilder
Indicates whether this builder is able to turn a resource of media type indicated by flavor into a table. It should return true if it thinks that its TableBuilder.streamStarTable(java.io.InputStream, uk.ac.starlink.table.TableSink, java.lang.String) method stands a reasonable chance of successfully constructing a StarTable from a DataSource whose input stream is described by the DataFlavor flavor. It will typically make this determination based on the flavor's MIME type.

This method should only return true if the flavor looks like it is targeted at this builder; for instance a builder which uses a text-based format should return false for a flavor which indicates a MIME type of text/plain.

This method is used in supporting drag and drop functionality (see StarTableFactory.canImport(java.awt.datatransfer.DataFlavor[])).

Specified by:
canImport in interface TableBuilder
Parameters:
flavor - the DataFlavor whose suitability as stream input is to be assessed
Returns:
true iff this builder reckons it stands a good chance of turning a stream of type flavor into a StarTable

makeStarTable

public StarTable makeStarTable(DataSource datsrc,
                               boolean wantRandom,
                               StoragePolicy policy)
                        throws java.io.IOException
Description copied from interface: TableBuilder
Constructs a StarTable based on a given DataSource. If the source is not recognised or this builder does not know how to construct a table from it, then a TableFormatException should be thrown. If this builder thinks it should be able to handle the source but an error occurs during processing, an IOException can be thrown.

The wantRandom parameter is used to indicate whether, ideally, a random-access table should be returned. There is no requirement for the builder to honour this request, but if it knows how to make both random and non-random tables, it can use this flag to decide which to return.

Note: the presence of the wantRandom parameter is somewhat misleading. TableBuilder implementations usually should, and do, ignore it (it would be removed from the interface if it were not for backward compatibility issues). Regardless of the value of this parameter, implementations should return a random-access table only if it is easy for them to do so; in particular they should not use the supplied storagePolicy, or any other resource-expensive measure, to randomise a sequential table just because the wantRandom parameter is true.

Specified by:
makeStarTable in interface TableBuilder
Parameters:
datsrc - the DataSource containing the table resource
wantRandom - whether, preferentially, a random access table should be returned
policy - a StoragePolicy object which may be used to supply scratch storage if the builder needs it
Returns:
a StarTable made out of datsrc
Throws:
TableFormatException - if the table is not of a kind that can be handled by this handler
java.io.IOException - if an unexpected I/O error occurs during processing

streamStarTable

public void streamStarTable(java.io.InputStream in,
                            TableSink sink,
                            java.lang.String pos)
                     throws java.io.IOException
Description copied from interface: TableBuilder
Reads a table from an input stream and writes it a row at a time to a sink. Not all implementations will be able to do this; for instance, extracting the table from the data may be a two-pass process. Implementations which are unable to perform this function should throw a TableFormatException.

The input stream should be prepared for use prior to calling this method, so implementations should not in general attempt to decompress or buffer istrm.

Specified by:
streamStarTable in interface TableBuilder
Parameters:
in - input stream containing table data
sink - destination of the table
pos - position identifier describing the location of the table within the stream; see DataSource.getPosition() (may be null)
Throws:
TableFormatException - if the table can't be streamed or the data is malformed
java.io.IOException - if some other error occurs

Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved.