/
FourthRatings.java
164 lines (135 loc) · 5.49 KB
/
FourthRatings.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
/**
* Write a description of class FourthRatings here.
*
* @author (your name)
* @version (a version number or a date)
*/
import java.util.*;
public class FourthRatings
{
public FourthRatings() {
this("ratings.csv");
}
public FourthRatings(String ratingsfile) {;
RaterDatabase.addRatings("data/" + ratingsfile);
}
private double getAverageByID(String id, int minimalRaters){
double count = 0.0;
double sum = 0.0;
for(Rater r : RaterDatabase.getRaters()){
if(r.hasRating(id)) {
sum += r.getRating(id);
count ++;
}
}
return (count >= minimalRaters) ? (double)(sum/count) : 0.0;
}
public ArrayList<Rating> getAverageRatings( int minimalRaters) {
ArrayList<Rating> averageRatings = new ArrayList<Rating>();
ArrayList<String> movies = MovieDatabase.filterBy(new TrueFilter());
for (String movieID : movies) {
double rating = getAverageByID(movieID, minimalRaters);
Rating movieAvgRate = new Rating(movieID, rating);
if(rating != 0){
averageRatings.add(movieAvgRate);
}
}
return averageRatings;
}
public ArrayList<Rating> getAverageRatingsByFilter(int minimalRaters,
Filter filterCriteria){
ArrayList<Rating> avgRatingsByFilter = new ArrayList<Rating>();
ArrayList<String> movies = MovieDatabase.filterBy(filterCriteria);
for (String movieID : movies){
double avgRating = getAverageByID(movieID, minimalRaters);
if(avgRating != 0){
Rating movieAvgRate = new Rating(movieID, avgRating);
avgRatingsByFilter.add(movieAvgRate);
}
}
return avgRatingsByFilter;
}
private double dotProduct(Rater me, Rater r){
// translate ratings from (0 to 10) to (-5 to 5)
double dotProduct = 0;
ArrayList<String> myRatedMovies = me.getItemsRated();
for (String id : myRatedMovies) {
if (r.hasRating(id)) {
double myRating = me.getRating(id);
double rRating = r.getRating(id);
myRating -= 5;
rRating -= 5;
dotProduct += myRating * rRating;
}
}
return dotProduct;
}
private ArrayList<Rating> getSimilarities(String id) {
ArrayList<Rating> list = new ArrayList<Rating>();
Rater me = RaterDatabase.getRater(id);
for (Rater r : RaterDatabase.getRaters()){
if (!r.equals(me)) {
double dotProd = dotProduct(me, r);
if (dotProd > 0) {
list.add(new Rating(r.getID(), dotProd));
}
}
}
Collections.sort(list, Collections.reverseOrder());
return list;
}
public ArrayList<Rating> getSimilarRatings( String id,
int numSimilarRaters, int minimalRaters) {
ArrayList<Rating> ret = new ArrayList<Rating>();
ArrayList<Rating> list = getSimilarities(id);
ArrayList<String> movies = MovieDatabase.filterBy(new TrueFilter());
for (String movieID : movies){
double weightedAverage = 0;
double sum = 0;
int countRaters = 0;
for(int k=0; k < numSimilarRaters; k++){
Rating r = list.get(k);
double weight = r.getValue();
String raterID = r.getItem();
Rater myRater = RaterDatabase.getRater(raterID);
if(myRater.hasRating(movieID)) {
countRaters ++;
sum += weight * myRater.getRating(movieID);
}
}
if (countRaters >= minimalRaters){
weightedAverage = sum / countRaters;
ret.add(new Rating(movieID, weightedAverage));
}
}
Collections.sort(ret, Collections.reverseOrder());
return ret;
}
public ArrayList<Rating> getSimilarRatingsByFilter( String id, int numSimilarRaters,
int minimalRaters, Filter filterCriteria ) {
ArrayList<Rating> ret = new ArrayList<Rating>();
ArrayList<Rating> list = getSimilarities(id);
ArrayList<String> movies = MovieDatabase.filterBy(filterCriteria);
for (String movieID : movies){
double weightedAverage = 0;
double sum = 0;
int countRaters = 0;
for(int k=0; k < numSimilarRaters; k++){
Rating r = list.get(k);
double weight = r.getValue();
String raterID = r.getItem();
Rater myRater = RaterDatabase.getRater(raterID);
if(myRater.hasRating(movieID)) {
countRaters ++;
sum += weight * myRater.getRating(movieID);
}
}
if (countRaters >= minimalRaters){
weightedAverage = sum / countRaters;
ret.add(new Rating(movieID, weightedAverage));
}
}
Collections.sort(ret, Collections.reverseOrder());
return ret;
}
}