code: public static ITileSource getTileSource(final String aName) throws IllegalArgumentException {
  		for (final ITileSource tileSource : mTileSources) {
  			if (tileSource.name().equals(aName)) {
  				return tileSource;
  			}
  		}
  		throw new IllegalArgumentException("No such tile source: " + aName);
  	}
docs: Get the tile source with the specified name. The tile source must be one of the registered sources
  as defined in the static list mTileSources of this class.
  
  @param aName
  the tile source name
  @return the tile source
  @throws IllegalArgumentException
  if tile source not found