uk.ac.starlink.gbin.GbinTableBuilder Maven / Gradle / Ivy
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Starlink Tables Infrastructure Library
package uk.ac.starlink.gbin;
import java.awt.datatransfer.DataFlavor;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import uk.ac.starlink.table.DefaultValueInfo;
import uk.ac.starlink.table.DescribedValue;
import uk.ac.starlink.table.RowSequence;
import uk.ac.starlink.table.StarTable;
import uk.ac.starlink.table.StoragePolicy;
import uk.ac.starlink.table.TableFormatException;
import uk.ac.starlink.table.TableSink;
import uk.ac.starlink.table.ValueInfo;
import uk.ac.starlink.table.WrapperRowSequence;
import uk.ac.starlink.table.formats.DocumentedTableBuilder;
import uk.ac.starlink.util.DataSource;
/**
* TableBuilder implementation for GBIN files.
*
* @author Mark Taylor
* @since 14 Aug 2014
*/
public class GbinTableBuilder extends DocumentedTableBuilder {
private final GbinTableProfile profile_;
/** ValueInfo for GBIN row object classname. */
public static final ValueInfo CLASSNAME_INFO =
new DefaultValueInfo( "GbinClass", String.class,
"Classname of GBIN objects" );
/** ValueInfo for well-known Gaia table name. */
public static final ValueInfo GAIATABLENAME_INFO =
new DefaultValueInfo( "GaiaTableName", String.class,
"Well-known name of Gaia table" );
/** ValueInfo for Gaia table description string. */
public static final ValueInfo DESCRIP_INFO =
new DefaultValueInfo( "Description", String.class,
"Table description from Gaia data model" );
/** ValueInfo for Gaia column detailed description string. */
public static final ValueInfo COLDETAIL_INFO =
new DefaultValueInfo( "GaiaDetail", String.class,
"Detailed column description"
+ " from Gaia data model" );
/** ValueInfo for GBIN build description string. */
public static final ValueInfo BUILDDESCRIP_INFO =
new DefaultValueInfo( "GbinDescription", String.class,
"GBIN build description" );
/**
* Constructs a builder with default options.
*/
public GbinTableBuilder() {
this( new DefaultGbinTableProfile() );
}
/**
* Constructs a builder with custom options.
*
* @param profile configures how GBIN files will be mapped to a table
*/
public GbinTableBuilder( GbinTableProfile profile ) {
super( new String[] { "gbin" } );
profile_ = profile;
}
/**
* Returns the object configuring how GBIN files are mapped to tables.
*
* @return configuration profile
*/
public GbinTableProfile getProfile() {
return profile_;
}
/**
* Returns "GBIN".
*/
public String getFormatName() {
return "GBIN";
}
public boolean canImport( DataFlavor flavor ) {
return false;
}
public void streamStarTable( InputStream in, TableSink sink, String pos )
throws IOException {
try {
GbinObjectReader reader = GbinObjectReader.createReader( in );
if ( ! reader.hasNext() ) {
throw new IOException( "No objects in GBIN file" );
}
Object gobj0 = reader.next();
GbinStarTable table =
new GbinStarTable( profile_, gobj0.getClass() ) {
public long getRowCount() {
return -1;
}
public RowSequence getRowSequence() {
throw new UnsupportedOperationException();
}
};
sink.acceptMetadata( table );
RowSequence rseq = table.createRowSequence( reader, gobj0 );
while ( rseq.next() ) {
sink.acceptRow( rseq.getRow() );
}
sink.endRows();
rseq.close();
}
finally {
in.close();
}
}
public StarTable makeStarTable( final DataSource datsrc, boolean wantRandom,
StoragePolicy storage )
throws IOException {
/* If required, check the magic number of the input file. */
if ( profile_.isTestMagic() &&
! GbinObjectReader.isMagic( datsrc.getIntro() ) ) {
throw new TableFormatException( "Not GBIN" );
}
/* Read an object out of the file to find out the data type. */
InputStream in = new BufferedInputStream( datsrc.getInputStream() );
GbinObjectReader rdr = GbinObjectReader.createReader( in );
if ( ! rdr.hasNext() ) {
throw new IOException( "No objects in GBIN file" );
}
Class gobjClazz = rdr.next().getClass();
in.close();
/* If required, read the start of the file again to obtain
* non-essential metadata. This requires another read, since the
* way GBIN files and the GaiaTools reader API are arranged,
* pretty much anything you read from a GBIN file makes it
* useless for reading anything else. */
final long nrow;
final List params = new ArrayList();
if ( profile_.isReadMeta() ) {
Long nrowObj;
InputStream metaIn =
new BufferedInputStream( datsrc.getInputStream() );
try {
Object gbinRdrObj =
GbinObjectReader.createGbinReaderObject( metaIn );
GbinMeta meta =
GbinMetadataReader.attemptReadMetadata( gbinRdrObj );
nrowObj = meta.getTotalElementCount();
params.add(
new DescribedValue( BUILDDESCRIP_INFO,
meta.buildDescription( false ) ) );
}
catch ( Throwable e ) {
nrowObj = null;
GbinObjectReader.logError( Level.WARNING,
"Couldn't read GBIN metadata", e );
}
finally {
metaIn.close();
}
nrow = nrowObj == null ? -1 : nrowObj.longValue();
}
else {
nrow = -1;
}
/* Construct a table with the metadata we have obtained,
* and return it. */
final long nrow0 = nrow;
StarTable table = new GbinStarTable( profile_, gobjClazz ) {
public RowSequence getRowSequence() throws IOException {
final InputStream in =
new BufferedInputStream( datsrc.getInputStream() );
GbinObjectReader reader = GbinObjectReader.createReader( in );
if ( ! reader.hasNext() ) {
throw new IOException( "No objects in GBIN file" );
}
Object gobj0 = reader.next();
return new WrapperRowSequence( createRowSequence( reader,
gobj0 ) ) {
@Override
public void close() throws IOException {
in.close();
}
};
}
public long getRowCount() {
return nrow0;
}
};
for ( DescribedValue param : params ) {
table.setParameter( param );
}
return table;
}
public boolean canStream() {
return true;
}
public boolean docIncludesExample() {
return false;
}
public String getXmlDescription() {
return readText( "GbinTableBuilder.xml" );
}
}