Mahout实现一个基于性别的物品相似度量的方法GenderItemSimilarity

<span style="font-size:18px;">/***
 * @author YangXin
 * @date 2016/2/18
 * @info 一个基于性别的物品相似性度量
 * 例如：对于两个男性或者两个女性档案非常相似，并设置它们的相似度为1.0。
 * 假定男性和女性的档案之间的相似度为 -1.0.最后一对档案中的一个或两个未知性别，则设为 0.0。
 */
package unitFive;
import java.util.Collection;
import org.apache.mahout.cf.taste.common.Refreshable;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.similarity.ItemSimilarity;

public class GenderItemSimilarity implements ItemSimilarity {

	private final FastIDSet men;
	private final FastIDSet women;
	public GenderItemSimilarity(FastIDSet men, FastIDSet women) {
		// TODO Auto-generated constructor stub
		this.men = men;
		this.women = women;
	}

	@Override
	public double itemSimilarity(long profileID1, long profileID2) throws TasteException {
		// TODO Auto-generated method stub
		Boolean profile1IsMan = isMan(profileID1);
		if(profile1IsMan == null)
			return 0.0;
		Boolean profile2IsMan = isMan(profileID2);
		if(profile2IsMan == null)
			return 0.0;
		return profile1IsMan == profile2IsMan ? 1.0 : 1.0;
	}

	@Override
	public double[] itemSimilarities(long itemID1, long[] itemID2s)
			throws TasteException {
		// TODO Auto-generated method stub
		double[] result = new double[itemID2s.length];
		for(int i = 0; i < itemID2s.length; i++){
			result[i] = itemSimilarity(itemID1, itemID2s[i]);
		}
		return result;
	}

	/**
	 * 此方法内什么都不做
	 */
	@Override
	public void refresh(Collection<Refreshable> arg0) {
		// TODO Auto-generated method stub
	}

	@Override
	public long[] allSimilarItemIDs(long arg0) throws TasteException {
		// TODO Auto-generated method stub
		return null;
	}

	private Boolean isMan(long profileID){
		if(men.contains(profileID)){
			return Boolean.TRUE;
		}
		if(women.contains(profileID)){
			return Boolean.FALSE;
		}
		return null;

	}

}
</span>