Skip to content

Commit b0634c7

Browse files
lewysDavieslewysDavies
committed
Added version to JavaDoc
1 parent b00d879 commit b0634c7

File tree

1 file changed

+141
-141
lines changed

1 file changed

+141
-141
lines changed

‎src/test/java/com/lewdev/probabilitylib/ProbabilityMap.java‎

Lines changed: 141 additions & 141 deletions
Original file line numberDiff line numberDiff line change
@@ -1,142 +1,142 @@
1-
package com.lewdev.probabilitylib;
2-
3-
import java.util.LinkedHashMap;
4-
import java.util.Map;
5-
import java.util.Map.Entry;
6-
import java.util.concurrent.ThreadLocalRandom;
7-
import java.util.stream.Collectors;
8-
9-
/**
10-
* ProbabilityMap to easily handle probability <br>
11-
* <br>
12-
*
13-
* <b>Selection Algorithm Implementation</b>:
14-
* <p>
15-
* <ul>
16-
* <li>Elements have a "box" of space, sized based on their probability share
17-
* <li>"Boxes" start from index 1 and end at the total probability of elements
18-
* <li>A random number is selected between 1 and the total probability
19-
* <li>Which "box" the random number falls in is the element that is selected
20-
* <li>Therefore "boxes" with larger probability have a greater chance of being
21-
* selected than those with smaller probability.
22-
* </p>
23-
* </ul>
24-
*
25-
* @param <E> Type of elements
26-
*
27-
* @author Lewys Davies
28-
*/
29-
public class ProbabilityMap<E> {
30-
31-
private LinkedHashMap<E, Integer> map = new LinkedHashMap<>();
32-
33-
private int totalProbability = 0;
34-
35-
/**
36-
* Construct a empty probability map
37-
*/
38-
public ProbabilityMap() {
39-
}
40-
41-
/**
42-
* Construct a probability map with initial elements
43-
*
44-
* @param elements
45-
*/
46-
public ProbabilityMap(Map<E, Integer> elements) {
47-
this.addAll(elements);
48-
}
49-
50-
/**
51-
* Add a element to the map
52-
*
53-
* @param element
54-
* @param probability x > 0
55-
*/
56-
public final boolean add(E element, int probability) {
57-
this.map.put(element, probability);
58-
this.updateState();
59-
return true;
60-
}
61-
62-
/**
63-
* Add all elements from a different map to this one
64-
*
65-
* @param elements
66-
*/
67-
public final void addAll(Map<E, Integer> elements) {
68-
this.map.putAll(elements);
69-
this.updateState();
70-
}
71-
72-
/**
73-
* Get a random element from the map
74-
*
75-
* @return Random element based on probability | null if map is empty
76-
*/
77-
public final E get() {
78-
if (this.map.isEmpty())
79-
return null;
80-
81-
// Map is sorted when changed
82-
// Therefore probability of elements is already in descending order: i.e. 5, 5,
83-
// 4, 1, 1
84-
85-
// Random int between 1 and total probability (+1 as nextInt bound is exclusive)
86-
int randomProb = ThreadLocalRandom.current().nextInt(1, this.totalProbability + 1);
87-
88-
int cumulativeProb = 0;
89-
E selectedElm = null;
90-
91-
for (Entry<E, Integer> entry : this.map.entrySet()) {
92-
// Calculate the size of this elements box: i.e 1-5, 6-10, 11-14, 15, 16
93-
int boxStart = cumulativeProb + 1;
94-
int boxEnd = boxStart + (entry.getValue() - 1);
95-
96-
// Check if the elements box falls within the randomly chosen index
97-
if (randomProb >= boxStart && randomProb <= boxEnd) {
98-
selectedElm = entry.getKey();
99-
break;
100-
}
101-
102-
// If not keep searching
103-
cumulativeProb = boxEnd;
104-
}
105-
106-
return selectedElm;
107-
}
108-
109-
/**
110-
* Remove a element from the map
111-
*
112-
* @param element
113-
*/
114-
public final void remove(E element) {
115-
this.map.remove(element);
116-
this.updateState();
117-
}
118-
119-
/**
120-
* Remove all elements from the map
121-
*/
122-
public final void clear() {
123-
this.map.clear();
124-
this.updateState();
125-
}
126-
127-
/**
128-
* @return Sum of all the element's probability
129-
*/
130-
public final int getTotalProbability() {
131-
return this.totalProbability;
132-
}
133-
134-
private final void updateState() {
135-
// Update total probability cache
136-
this.totalProbability = this.map.values().stream().mapToInt(Integer::intValue).sum();
137-
138-
// Sort LinkedHashMap
139-
this.map = this.map.entrySet().stream().sorted(Map.Entry.<E, Integer>comparingByValue().reversed())
140-
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (x, y) -> y, LinkedHashMap::new));
141-
}
1+
package com.lewdev.probabilitylib;
2+
3+
import java.util.LinkedHashMap;
4+
import java.util.Map;
5+
import java.util.Map.Entry;
6+
import java.util.concurrent.ThreadLocalRandom;
7+
import java.util.stream.Collectors;
8+
9+
/**
10+
* ProbabilityMap to easily handle probability <br>
11+
* <br>
12+
*
13+
* <b>Selection Algorithm Implementation</b>:
14+
* <p>
15+
* <ul>
16+
* <li>Elements have a "box" of space, sized based on their probability share
17+
* <li>"Boxes" start from index 1 and end at the total probability of elements
18+
* <li>A random number is selected between 1 and the total probability
19+
* <li>Which "box" the random number falls in is the element that is selected
20+
* <li>Therefore "boxes" with larger probability have a greater chance of being
21+
* selected than those with smaller probability.
22+
* </p>
23+
* </ul>
24+
*
25+
* @param <E> Type of elements
26+
* @version 0.5
27+
*
28+
* @author Lewys Davies
29+
*/
30+
public class ProbabilityMap<E> {
31+
32+
private LinkedHashMap<E, Integer> map = new LinkedHashMap<>();
33+
34+
private int totalProbability = 0;
35+
36+
/**
37+
* Construct a empty probability map
38+
*/
39+
public ProbabilityMap() { }
40+
41+
/**
42+
* Construct a probability map with initial elements
43+
*
44+
* @param elements
45+
*/
46+
public ProbabilityMap(Map<E, Integer> elements) {
47+
this.addAll(elements);
48+
}
49+
50+
/**
51+
* Add a element to the map
52+
*
53+
* @param element
54+
* @param probability x > 0
55+
*/
56+
public final boolean add(E element, int probability) {
57+
this.map.put(element, probability);
58+
this.updateState();
59+
return true;
60+
}
61+
62+
/**
63+
* Add all elements from a different map to this one
64+
*
65+
* @param elements
66+
*/
67+
public final void addAll(Map<E, Integer> elements) {
68+
this.map.putAll(elements);
69+
this.updateState();
70+
}
71+
72+
/**
73+
* Get a random element from the map
74+
*
75+
* @return Random element based on probability | null if map is empty
76+
*/
77+
public final E get() {
78+
if (this.map.isEmpty())
79+
return null;
80+
81+
// Map is sorted when changed
82+
// Therefore probability of elements is already in descending order: i.e. 5, 5,
83+
// 4, 1, 1
84+
85+
// Random int between 1 and total probability (+1 as nextInt bound is exclusive)
86+
int randomProb = ThreadLocalRandom.current().nextInt(1, this.totalProbability + 1);
87+
88+
int cumulativeProb = 0;
89+
E selectedElm = null;
90+
91+
for (Entry<E, Integer> entry : this.map.entrySet()) {
92+
// Calculate the size of this elements box: i.e 1-5, 6-10, 11-14, 15, 16
93+
int boxStart = cumulativeProb + 1;
94+
int boxEnd = boxStart + (entry.getValue() - 1);
95+
96+
// Check if the elements box falls within the randomly chosen index
97+
if (randomProb >= boxStart && randomProb <= boxEnd) {
98+
selectedElm = entry.getKey();
99+
break;
100+
}
101+
102+
// If not keep searching
103+
cumulativeProb = boxEnd;
104+
}
105+
106+
return selectedElm;
107+
}
108+
109+
/**
110+
* Remove a element from the map
111+
*
112+
* @param element
113+
*/
114+
public final void remove(E element) {
115+
this.map.remove(element);
116+
this.updateState();
117+
}
118+
119+
/**
120+
* Remove all elements from the map
121+
*/
122+
public final void clear() {
123+
this.map.clear();
124+
this.updateState();
125+
}
126+
127+
/**
128+
* @return Sum of all the element's probability
129+
*/
130+
public final int getTotalProbability() {
131+
return this.totalProbability;
132+
}
133+
134+
private final void updateState() {
135+
// Update total probability cache
136+
this.totalProbability = this.map.values().stream().mapToInt(Integer::intValue).sum();
137+
138+
// Sort LinkedHashMap
139+
this.map = this.map.entrySet().stream().sorted(Map.Entry.<E, Integer>comparingByValue().reversed())
140+
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (x, y) -> y, LinkedHashMap::new));
141+
}
142142
}

0 commit comments

Comments
 (0)