uk.ac.starlink.table.formats

Class CoinsTableBuilder

java.lang.Object

uk.ac.starlink.table.formats.CoinsTableBuilder

All Implemented Interfaces:

TableBuilder

public class CoinsTableBuilder
extends 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

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
CoinsTableBuilder()

Method Summary

Modifier and Type	Method and Description
boolean	canImport(DataFlavor flavor) Indicates whether this builder is able to turn a resource of media type indicated by flavor into a table.
String	getFormatName() Returns "COINS".
boolean	looksLikeFile(String location) Indicates whether the given location string is of a familiar form for this builder.
StarTable	makeStarTable(DataSource datsrc, boolean wantRandom, StoragePolicy policy) Constructs a StarTable based on a given DataSource.
void	streamStarTable(InputStream in, TableSink sink, 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 String getFormatName()

Returns "COINS".

Specified by:

getFormatName in interface TableBuilder

Returns:

one-word description of this handler's format

looksLikeFile

public boolean looksLikeFile(String location)

Description copied from interface: TableBuilder

Indicates whether the given location string is of a familiar form for this builder. Implementations should return true if there is a good chance that a file with the given location can be interpreted by this reader, for instance if it has a suitable file extension.

This method may be used to guess, on a best-efforts basis, whether this builder is suitable for reading a file from a given location. Attempts may still be made to read inputs for which this method returns false. It is less important for builders that can recognise files by magic number, which is generally preferable to using filenames.

Specified by:

looksLikeFile in interface TableBuilder

Parameters:

location - the location string, such as a filename or URL (not null)

Returns:

true iff there is a good chance that the named input can be interpreted by this reader

canImport

public boolean canImport(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 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

IOException - if an unexpected I/O error occurs during processing

streamStarTable

public void streamStarTable(InputStream in,
                            TableSink sink,
                            String pos)
                     throws 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

IOException - if some other error occurs