import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
@Override
public void refresh(Collection<Refreshable> collection) {
    userCache.clear();
    itemCache.clear();
    userIDsFromItemCache.clear();
    itemIDsFromUserCache.clear();
    userCountCache.set(null);
    itemCountCache.set(null);
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
/**
 * Get the similarity instance that is used to check which users and items
 * are similar. There are several implementations for this, these are specified
 * by the this.alg value of the RecommendEntityServlet instance.
 * NOTE: Since there are two interfaces: ItemSimilarity and UserSimilarity the
 * returned type is of the interface Refreshable since both interfaces inherit
 * that type as well. Cast it to the right type.
 * @param model The database model to use for the similarity calculations
 * @return The UserSimilarity or ItemSimilarity instance.
 * @throws TasteException If an exception is thrown by Mahout it is forwarded upwards.
 */
private Refreshable getSimularity(DataModel model) throws TasteException {
    if(this.alg.equalsIgnoreCase(A_EUCLIDEAN)){
        return new EuclideanDistanceSimilarity(model);
    } else if(this.alg.equalsIgnoreCase(A_PEARSON)){
        return new PearsonCorrelationSimilarity(model);
    } else if(this.alg.equalsIgnoreCase(A_TANIMOTO)){
        return new TanimotoCoefficientSimilarity(model);
    } else if(this.alg.equalsIgnoreCase(A_LOGLIKELIHOOD) || this.alg == null){ // == null is the default case
        return new LogLikelihoodSimilarity(model);
    } else {
        throw new TasteException("Unknown algorithm type: " + this.alg);
    }
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed)
{
	// TODO Auto-generated method stub
	// probably do nothing -

}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
@Deprecated
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed) {
  if (alreadyRefreshed != null) {
    log.warn("Ignoring argument {}", alreadyRefreshed);
  }
  refresh();
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed) {
    easyrecDataModelDelegate.refresh(alreadyRefreshed);
    intializeDelegate();
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
@Override
public void refresh(final Collection<Refreshable> clctn) {
    wrapper.refresh(clctn);
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
/**
 * @deprecated call {@link #refresh()}
 */
@Deprecated
@Override
void refresh(Collection<Refreshable> refreshables);
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
/**
 * <p>
 * Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any
 * should always leave itself in a consistent, operational state, and that the refresh
 * atomically updates internal state from old to new.
 * </p>
 *
 * @param alreadyRefreshed s that are known to have already been
 *                         refreshed as a result of an initial call to a  method on some
 *                         object. This ensure that objects in a refresh dependency graph aren't refreshed twice
 *                         needlessly.
 */
public void refresh(Collection<Refreshable> alreadyRefreshed) {
    cutoffDate = new Date();
}
 

import org.apache.mahout.cf.taste.common.Refreshable; //导入依赖的package包/类
/**
 * Refresh the recommender.
 *
 * @param clctn the data.
 */
@Override
public void refresh(final Collection<Refreshable> clctn) {
}