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package uk.ac.bristol.star.cdf.record;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;
import uk.ac.bristol.star.cdf.CdfFormatException;
/**
* Turns bytes in a buffer into typed and populated CDF records.
*
* @author Mark Taylor
* @since 18 Jun 2013
*/
public class RecordFactory {
private final Map<Integer,TypedRecordFactory> factoryMap_;
private final Logger logger_ =
Logger.getLogger( RecordFactory.class.getName() );
/**
* Constructor.
*
* @param nameLeng number of bytes in variable and attribute names;
* appears to be 64 for pre-v3 and 256 for v3
*/
public RecordFactory( int nameLeng ) {
factoryMap_ = createFactoryMap( nameLeng );
}
/**
* Creates a Record object from a given position in a buffer.
* The returned object will be an instance of one of the
* Record subclasses as appropriate for its type.
*
* @param buf byte buffer
* @param offset start of record in buf
* @return record
*/
public Record createRecord( Buf buf, long offset ) throws IOException {
Pointer ptr = new Pointer( offset );
long recSize = buf.readOffset( ptr );
int recType = buf.readInt( ptr );
RecordPlan plan = new RecordPlan( offset, recSize, recType, buf );
TypedRecordFactory tfact = factoryMap_.get( recType );
if ( tfact == null ) {
throw new CdfFormatException( "Unknown record type " + recType );
}
else {
Record rec = tfact.createRecord( plan );
String msg = new StringBuffer()
.append( "CDF Record:\t" )
.append( "0x" )
.append( Long.toHexString( offset ) )
.append( "\t+" )
.append( recSize )
.append( "\t" )
.append( rec.getRecordTypeAbbreviation() )
.toString();
logger_.config( msg );
return rec;
}
}
/**
* Creates a Record object with a known type from a given position in
* a buffer. This simply calls the untyped <code>getRecord</code>
* method, and attempts to cast the result, throwing a
* CdfFormatException if it has the wrong type.
*
* @param buf byte buffer
* @param offset start of record in buf
* @param clazz record class asserted for the result
* @return record
* @throws CdfFormatException if the record found there turns out
* not to be of type <code>clazz</code>
*/
public <R extends Record> R createRecord( Buf buf, long offset,
Class<R> clazz )
throws IOException {
Record rec = createRecord( buf, offset );
if ( clazz.isInstance( rec ) ) {
return clazz.cast( rec );
}
else {
String msg = new StringBuffer()
.append( "Unexpected record type at " )
.append( "0x" )
.append( Long.toHexString( offset ) )
.append( "; got " )
.append( rec.getClass().getName() )
.append( " not " )
.append( clazz.getName() )
.toString();
throw new CdfFormatException( msg );
}
}
/**
* Sets up a mapping from CDF RecordType codes to factories for the
* record types in question.
*
* @return map of record type to record factory
*/
private static Map<Integer,TypedRecordFactory>
createFactoryMap( final int nameLeng ) {
Map<Integer,TypedRecordFactory> map =
new HashMap<Integer,TypedRecordFactory>();
map.put( 1, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new CdfDescriptorRecord( plan );
}
} );
map.put( 2, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new GlobalDescriptorRecord( plan );
}
} );
map.put( 4, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new AttributeDescriptorRecord( plan, nameLeng );
}
} );
map.put( 5, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new AttributeEntryDescriptorRecord.GrVariant( plan );
}
} );
map.put( 9, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new AttributeEntryDescriptorRecord.ZVariant( plan );
}
} );
map.put( 3, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new VariableDescriptorRecord.RVariant( plan, nameLeng );
}
} );
map.put( 8, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new VariableDescriptorRecord.ZVariant( plan, nameLeng );
}
} );
map.put( 6, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new VariableIndexRecord( plan );
}
} );
map.put( 7, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new VariableValuesRecord( plan );
}
} );
map.put( 10, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new CompressedCdfRecord( plan );
}
} );
map.put( 11, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new CompressedParametersRecord( plan );
}
} );
map.put( 12, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new SparsenessParametersRecord( plan );
}
} );
map.put( 13, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new CompressedVariableValuesRecord( plan );
}
} );
map.put( -1, new TypedRecordFactory() {
public Record createRecord( RecordPlan plan ) throws IOException {
return new UnusedInternalRecord( plan );
}
} );
int[] recTypes = new int[ map.size() ];
int irt = 0;
for ( int recType : map.keySet() ) {
recTypes[ irt++ ] = recType;
}
Arrays.sort( recTypes );
assert Arrays.equals( recTypes, new int[] { -1, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13 } );
return Collections.unmodifiableMap( map );
}
/**
* Object which can generate a particular record type from a plan.
*/
private static interface TypedRecordFactory<R extends Record> {
/**
* Creates a record from bytes.
*
* @param plan basic record information
* @return record
*/
R createRecord( RecordPlan plan ) throws IOException;
}
}
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