public void flush()

in mavibot/src/main/java/org/apache/directory/mavibot/btree/InMemoryBTree.java [499:577]
54 lines of code
7 McCabe index (conditional complexity)

    public void flush( File file ) throws IOException
    {
        File parentFile = file.getParentFile();
        File baseDirectory = null;

        if ( parentFile != null )
        {
            baseDirectory = new File( file.getParentFile().getAbsolutePath() );
        }
        else
        {
            baseDirectory = new File( "." );
        }

        // Create a temporary file in the same directory to flush the current btree
        File tmpFileFD = File.createTempFile( "mavibot", null, baseDirectory );
        FileOutputStream stream = new FileOutputStream( tmpFileFD );
        FileChannel ch = stream.getChannel();

        // Create a buffer containing 200 4Kb pages (around 1Mb)
        ByteBuffer bb = ByteBuffer.allocateDirect( writeBufferSize );

        try
        {
            TupleCursor<K, V> cursor = browse();

            if ( keySerializer == null )
            {
                throw new MissingSerializerException( "Cannot flush the btree without a Key serializer" );
            }

            if ( valueSerializer == null )
            {
                throw new MissingSerializerException( "Cannot flush the btree without a Value serializer" );
            }

            // Write the number of elements first
            bb.putLong( getBtreeHeader().getNbElems() );

            while ( cursor.hasNext() )
            {
                Tuple<K, V> tuple = cursor.next();

                byte[] keyBuffer = keySerializer.serialize( tuple.getKey() );

                writeBuffer( ch, bb, keyBuffer );

                byte[] valueBuffer = valueSerializer.serialize( tuple.getValue() );

                writeBuffer( ch, bb, valueBuffer );
            }

            // Write the buffer if needed
            if ( bb.position() > 0 )
            {
                bb.flip();
                ch.write( bb );
            }

            // Flush to the disk for real
            ch.force( true );
            ch.close();
        }
        catch ( KeyNotFoundException knfe )
        {
            knfe.printStackTrace();
            throw new IOException( knfe.getMessage() );
        }

        // Rename the current file to save a backup
        File backupFile = File.createTempFile( "mavibot", null, baseDirectory );
        file.renameTo( backupFile );

        // Rename the temporary file to the initial file
        tmpFileFD.renameTo( file );

        // We can now delete the backup file
        backupFile.delete();
    }