package jalview.datamodel.features;

import java.util.HashMap;
import java.util.Map;

/**
 * A singleton to hold metadata about feature attributes, keyed by a unique
 * feature source identifier
 * 
 * @author gmcarstairs
 *
 */
public class FeatureSources
{
  private static FeatureSources instance = new FeatureSources();

  private Map<String, FeatureSourceI> sources;

  /**
   * Answers the singleton instance of this class
   * 
   * @return
   */
  public static FeatureSources getInstance()
  {
    return instance;
  }

  private FeatureSources()
  {
    sources = new HashMap<>();
  }

  /**
   * Answers the FeatureSource with the given unique identifier, or null if not
   * known
   * 
   * @param sourceId
   * @return
   */
  public FeatureSourceI getSource(String sourceId)
  {
    return sources.get(sourceId);
  }

  /**
   * Adds the given source under the given key. This will replace any existing
   * source with the same id, it is the caller's responsibility to ensure keys
   * are unique if necessary.
   * 
   * @param sourceId
   * @param source
   */
  public void addSource(String sourceId, FeatureSource source)
  {
    sources.put(sourceId, source);
  }
}