How to use

build

method

in

org.lenskit.LenskitRecommenderEngineBuilder

/**
 * Build the recommender engine.
 *
 * @return The built recommender engine, with {@linkplain ModelDisposition#EXCLUDED excluded}
 *         components removed.
 * @throws RecommenderBuildException if there is an error building the recommender.
 * @deprecated Use {@link #build(DataAccessObject)}
 */
@Deprecated
public LenskitRecommenderEngine build() throws RecommenderBuildException {
  return build(null);
}

/**
 * Build a LensKit recommender engine from a configuration.  The resulting recommender is
 * independent of any subsequent modifications to the configuration.
 *
 * @param config     The configuration.
 * @return The recommender engine.
 */
@SuppressWarnings("deprecation")
public static LenskitRecommenderEngine build(LenskitConfiguration config) throws RecommenderBuildException {
  return newBuilder().addConfiguration(config).build();
}

/**
 * Build a LensKit recommender engine from a configuration.  The resulting recommender is
 * independent of any subsequent modifications to the configuration.
 *
 * @param config     The configuration.
 * @param dao The data access object
 * @return The recommender engine.
 */
public static LenskitRecommenderEngine build(LenskitConfiguration config, DataAccessObject dao) throws RecommenderBuildException {
  return newBuilder().addConfiguration(config).build(dao);
}

private LenskitRecommenderEngine buildRecommenderEngine(DataAccessObject train) throws RecommenderBuildException {
  logger.debug("Starting recommender build");
  LenskitRecommenderEngineBuilder builder = new EvalEngineBuilder();
  builder.addConfiguration(sharedConfig);
  builder.addConfiguration(dataSet.getExtraConfiguration());
  for (LenskitConfiguration cfg: algorithm.getConfigurations()) {
    builder.addConfiguration(cfg);
  }
  return builder.build(train);
}

LenskitRecommenderEngine engine = builder.build(input.getDAO());
timer.stop();
logger.info("built recommender in {}", timer);

@Override
public void execute(Namespace opts) throws LenskitCommandException {
  Context ctx = new Context(opts);
  LenskitConfiguration dataConfig = ctx.input.getConfiguration();
  LenskitRecommenderEngineBuilder builder = LenskitRecommenderEngine.newBuilder();
  try {
    for (LenskitConfiguration config: ctx.environment.loadConfigurations(ctx.getConfigFiles())) {
      builder.addConfiguration(config);
    }
  } catch (IOException e) {
    throw new LenskitCommandException("error loading LensKit configuration", e);
  }
  builder.addConfiguration(dataConfig, ModelDisposition.EXCLUDED);
  Stopwatch timer = Stopwatch.createStarted();
  LenskitRecommenderEngine engine = builder.build(ctx.input.getDAO());
  timer.stop();
  logger.info("built model in {}", timer);
  File output = ctx.getOutputFile();
  CompressionMode comp = CompressionMode.autodetect(output);
  logger.info("writing model to {}", output);
  try (OutputStream raw = new FileOutputStream(output);
     OutputStream stream = comp.wrapOutput(raw)) {
    engine.write(stream);
  } catch (IOException e) {
    throw new LenskitCommandException("could not write output file", e);
  }
}

lre = LenskitRecommenderEngine.newBuilder()
               .addConfiguration(algorithm.getConfigurations().get(0))
               .build(limitedDao);
timer.stop();
logger.info("built model {} in {}", buildsCount, timer);

/**
 * Build the recommender engine.
 *
 * @return The built recommender engine, with {@linkplain ModelDisposition#EXCLUDED excluded}
 *         components removed.
 * @throws RecommenderBuildException if there is an error building the recommender.
 * @deprecated Use {@link #build(DataAccessObject)}
 */
@Deprecated
public LenskitRecommenderEngine build() throws RecommenderBuildException {
  return build(null);
}

/**
 * Build a LensKit recommender engine from a configuration.  The resulting recommender is
 * independent of any subsequent modifications to the configuration.
 *
 * @param config     The configuration.
 * @param dao The data access object
 * @return The recommender engine.
 */
public static LenskitRecommenderEngine build(LenskitConfiguration config, DataAccessObject dao) throws RecommenderBuildException {
  return newBuilder().addConfiguration(config).build(dao);
}

/**
 * Build a LensKit recommender engine from a configuration.  The resulting recommender is
 * independent of any subsequent modifications to the configuration.
 *
 * @param config     The configuration.
 * @return The recommender engine.
 */
@SuppressWarnings("deprecation")
public static LenskitRecommenderEngine build(LenskitConfiguration config) throws RecommenderBuildException {
  return newBuilder().addConfiguration(config).build();
}

/**
 * Build a recommender.
 *
 * @param defaults Additional configuration.  This configuration comes <em>before</em> the
 *                 algorithm's configuration, so it is overridden if appropriate.  It is used
 *                 for providing things such as DAOs.
 * @return The instantiated recommender.
 * @throws RecommenderBuildException
 */
public LenskitRecommender buildRecommender(@Nullable LenskitConfiguration defaults) throws RecommenderBuildException {
  LenskitRecommenderEngineBuilder builder = LenskitRecommenderEngine.newBuilder();
  if (defaults != null) {
    builder.addConfiguration(defaults);
  }
  for (LenskitConfiguration cfg: configurations) {
    builder.addConfiguration(cfg);
  }
  return builder.build().createRecommender();
}