我有一个名为DataModel的{{1}}的自定义实现
ListDataModel。
package com.recommender.models;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
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.impl.common.LongPrimitiveArrayIterator;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.model.GenericItemPreferenceArray;
import org.apache.mahout.cf.taste.impl.model.GenericUserPreferenceArray;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import com.recommender.util.utils;
public class ListDataModel<T> implements DataModel {
/**
*
*/
private static final long serialVersionUID = 1L;
private List<T> __lst = new ArrayList<T>();
private String __userColumnName;
private String __itemColumnName;
private String __referenceColumnName;
public ListDataModel(List<T> list, String userColumnName, String itemColumnName,String refColumnName) {
__lst = list;
__userColumnName = userColumnName;
__itemColumnName = itemColumnName;
__referenceColumnName = refColumnName;
}
@SuppressWarnings("unchecked")
@Override
public void refresh(Collection<Refreshable> arg0) {
__lst = arg0.stream().map(m->(T)m).collect(Collectors.toList());
}
@Override
public LongPrimitiveIterator getItemIDs() throws TasteException {
List<Long> list = __lst.stream().map((r) -> utils.GetLong(r, __itemColumnName)).distinct().collect(Collectors.toList());
return new LongPrimitiveArrayIterator(utils.tolongArray(list));
}
@Override
public FastIDSet getItemIDsFromUser(long arg0) throws TasteException {
List<Long> list = __lst.stream().filter(fil->utils.GetLong(fil, __userColumnName)==arg0).map((r) -> utils.GetLong(r, __itemColumnName)).distinct().collect(Collectors.toList());
return new FastIDSet(utils.tolongArray(list));
}
@Override
public float getMaxPreference() {
// return utils.GetFloat(__lst.stream().max(new ListComprator<>(__referenceColumnName)).get(),__referenceColumnName);
return Float.NaN;
}
@Override
public float getMinPreference() {
// return utils.GetFloat(__lst.stream().min(new ListComprator<>(__referenceColumnName)).get(),__referenceColumnName);
return Float.NaN;
}
@Override
public int getNumItems() throws TasteException {
Set<Long> set = new HashSet<>(__lst.size());
return __lst.stream().filter(p -> set.add(utils.GetLong(p, __itemColumnName))).distinct().collect(Collectors.toList()).size();
}
@Override
public int getNumUsers() throws TasteException {
return __lst.stream().map(p -> utils.GetLong(p, __userColumnName)).distinct().collect(Collectors.toList()).size();
}
@Override
public int getNumUsersWithPreferenceFor(long arg0) throws TasteException {
return (int) __lst.stream().filter(fil->utils.GetLong(fil, __itemColumnName)==arg0).count();
}
@Override
public int getNumUsersWithPreferenceFor(long arg0, long arg1) throws TasteException {
return (int) __lst.stream().filter(fil->utils.GetLong(fil, __itemColumnName)==arg0 && utils.GetLong(fil, __itemColumnName)==arg0 ).count();
}
@Override
public Long getPreferenceTime(long arg0, long arg1) throws TasteException {
return 0L;
}
@Override
public Float getPreferenceValue(long arg0, long arg1) throws TasteException {
List<T> list = __lst.stream().filter(fil->utils.GetLong(fil, __userColumnName)==arg0 && utils.GetLong(fil, __itemColumnName)==arg1 ).collect(Collectors.toList());
if(list.size()==0) return Float.NaN;
return utils.GetFloat(list.get(0),__referenceColumnName);
}
@Override
public PreferenceArray getPreferencesForItem(long arg0) throws TasteException {
return new GenericItemPreferenceArray(__lst.stream()
.filter(fil->utils.GetLong(fil, __itemColumnName)==arg0)
.map(m->new Preference<T>(m, __userColumnName, __itemColumnName, __referenceColumnName))
.collect(Collectors.toList()));
}
@Override
public PreferenceArray getPreferencesFromUser(long arg0) throws TasteException {
return new GenericUserPreferenceArray(__lst.stream()
.filter(fil->utils.GetLong(fil, __userColumnName)==arg0)
.map(m->new Preference<T>(m, __userColumnName, __itemColumnName, __referenceColumnName))
.collect(Collectors.toList()));
}
@Override
public LongPrimitiveIterator getUserIDs() throws TasteException {
List<Long> list = __lst.stream().map((r) -> utils.GetLong(r, __userColumnName)).distinct().collect(Collectors.toList());
return new LongPrimitiveArrayIterator(utils.tolongArray(list));
}
@Override
public boolean hasPreferenceValues() {
return true;
}
@Override
public void removePreference(long arg0, long arg1) throws TasteException {
__lst =__lst.stream().filter(fil->utils.GetLong(fil, __userColumnName)!=arg0 && utils.GetLong(fil, __itemColumnName)!=arg0).collect(Collectors.toList());
}
@Override
public void setPreference(long arg0, long arg1, float arg2) throws TasteException {
List<T> list = __lst.stream().filter(fil->utils.GetLong(fil, __userColumnName)==arg0 && utils.GetLong(fil, __itemColumnName)==arg0).collect(Collectors.toList());
if(list.size()==0) return;
utils.SetFloatValue(__lst.get(__lst.indexOf(list.get(0))),__referenceColumnName,arg2);
}
}
一切都很好，但是当我想使用此package com.recommender.util;
import java.lang.reflect.Field;
import java.util.List;
public class utils {
public static long[] tolongArray(List<Long> list) {
long[] items = new long[list.size()];
for (int i = 0; i < list.size(); i++) {
items[i]=list.get(i);
}
return items;
}
public static Long GetLong(Object obj,String name) {
String str = "";
try {
return Long.parseLong(getFiled(obj, name).get(obj).toString());
} catch (IllegalArgumentException | IllegalAccessException | SecurityException e) {
System.out.println(str);
System.out.println("Some error in getting Long from Field(com.recommender.util.GetLong)");
e.printStackTrace();
}
return 0L;
}
public static String GetString(Object obj,String name) {
try {
return getFiled(obj, name).get(obj).toString();
} catch (IllegalArgumentException | IllegalAccessException | SecurityException e) {
System.out.println("Some error in getting String from Field(com.recommender.util.GetString)");
e.printStackTrace();
}
return "";
}
public static Float GetFloat(Object obj,String name) {
try {
return Float.parseFloat(getFiled(obj, name).get(obj).toString());
} catch (IllegalArgumentException | IllegalAccessException | SecurityException e) {
System.out.println("Some error in getting String from Field(com.recommender.util.GetString)");
e.printStackTrace();
}
return 0F;
}
public static void SetFloatValue(Object obj,String name,Float value) {
try {
getFiled(obj, name).setFloat(obj, value);
} catch (IllegalArgumentException | IllegalAccessException e) {
System.out.println("Some error in getting String from Field(com.recommender.util.SetFloatValue)");
e.printStackTrace();
}
}
public static void SetLongValue(Object obj,String name,Long value) {
try {
getFiled(obj, name).setLong(obj, value);
} catch (IllegalArgumentException | IllegalAccessException e) {
System.out.println("Some error in getting String from Field(com.recommender.util.SetLongValue)");
e.printStackTrace();
}
}
private static Field getFiled(Object obj,String name) {
try {
return obj.getClass().getField(name);
} catch (NoSuchFieldException | SecurityException e) {
System.out.println("Some error in getting Filed(com.recommender.util.getFiled)");
e.printStackTrace();
}
return null;
}
}
来获取DataModel时，什么也没有返回，并且应用程序永不停止
neighborhoods。
package com.recommender.models;
public class Ratings {
public Long UserId;
public Long ISBN;
public Long Rate;
public Ratings(Long ui,Long isbn,Long rate) {
UserId = ui;
ISBN = isbn;
Rate = rate;
}
public String toString() {
return UserId.toString()+","+ISBN.toString()+","+Rate.toString();
}
}