fr.arakne.utils.value.helper.RandomUtil.createShared() - Code Metrics - Inspection of "Add value module with Colors, Interval and RandomU..." - Arakne/ArakneUtils - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Branch — master (27e47c)

by Vincent

created 2020-05-12 20:02 UTC

createShared() A

↳ Parent: fr.arakne.utils.value.helper.RandomUtil

Complexity

Conditions

Size

Total Lines	6
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	3
CRAP Score	1

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	1
eloc	4
c	1
b	0
f	0
dl	0
loc	6
ccs	3
cts	3
cp	1
crap	1
rs	10

/*
 * This file is part of ArakneUtils.
 *
 * ArakneUtils is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ArakneUtils is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with ArakneUtils.  If not, see <https://www.gnu.org/licenses/>.
 *
 * Copyright (c) 2017-2020 Vincent Quatrevieux
 */

package fr.arakne.utils.value.helper;

import fr.arakne.utils.value.Interval;

import java.util.*;

/**
 * Utility for random numbers
 *
 * This utility class must be used instead of the native {@link Random} class,
 * for create predictable random values on testing environment
 *
 * It's not recommended to share the RandomUtil instance between objects instances (i.e. store into a static field)
 * Each objects instance should have its own RandomUtil instance
 * But in case of short-life objects static instance of RandomUtil can be used when created using {@link RandomUtil#createShared()}
 */
final public class RandomUtil extends Random {
    /**
     * Testing mode ?
     * If set to true, the seed value will be fixed and random will be predictable
     */
    static private boolean testing = false;

    /**
     * List of instance which are shared between instances
     * This list is used for reset random seeds when enable testing mode
     *
     * @see RandomUtil#createShared()
     */
    final static private Collection<RandomUtil> sharedInstances = new ArrayList<>();

    public RandomUtil() {
        if (testing) {
            setSeed(0);
        }
    }

    /**
     * Get random number into [min, max] interval
     * The interval is inclusive
     *
     * If max if lower than min, min is returned
     */
    public int rand(int min, int max) {
        if (max <= min) {
            return min;
        }

        if (min == 0) {
            return nextInt(max + 1);
        }

        return nextInt((max - min) + 1) + min;
    }

    /**
     * Get random number into given interval
     * The interval is inclusive
     */
    public int rand(Interval interval) {
        return rand(interval.min(), interval.max());
    }

    /**
     * Get a random double between interval [0, max[
     *
     * @param max The maximum value (exclusive)
     */
    public double decimal(double max) {
        return nextDouble() * max;
    }

    /**
     * Get a random number from an interval
     */
    public int rand(int[] interval) {
        if (interval.length == 1 || interval[0] > interval[1]) {
            return interval[0];
        }

        return rand(interval[0], interval[1]);
    }

    /**
     * Get a random boolean value
     *
     * @param percent Percent of chance that the returned value is true.
     *                If the value is 100, this method will always returns true
     *                If the value is 0, the method will always returns false
     */
    public boolean bool(int percent) {
        return nextInt(100) < percent;
    }

    /**
     * Get a random boolean value
     * The returned value has same chance to be true or false
     *
     * This method is equivalent to `bool(50)`
     *
     * @see RandomUtil#bool(int)
     */
    public boolean bool() {
        return nextBoolean();
    }

    /**
     * Get a random boolean value following reverse chance
     * The return value if true with the probability of 1 / rate
     * Higher the rate value is, lower the probability is
     *
     * For rate = 2, the probability is 50% and its equivalent to call bool(50) or bool()
     * For rate = 100, the probability is 1% and its equivalent to call bool(1)
     *
     * @param rate The rate
     *
     * @return The random boolean value
     */
    public boolean reverseBool(int rate) {
        return nextInt(rate) == 0;
    }

    /**
     * Get a random value from an array of values
     * All elements has the same selection probability
     *
     * @param values The provided values
     *
     * @return One of the element of the array
     */
    public<T> T of(T[] values) {
        return values[nextInt(values.length)];
    }

    /**
     * Get a random value from an array of characters
     *
     * @see RandomUtil#of(Object[])
     */
    public char of(char[] values) {
        return values[nextInt(values.length)];
    }

    /**
     * Get a random value from a list of values
     * All elements has the same selection probability
     *
     * @param values The provided values
     *
     * @return One of the element of the list
     */
    public<T> T of(List<T> values) {
        return values.get(nextInt(values.size()));
    }

    /**
     * Randomize list element positions
     * This method will create a copy of the list, without modify the input parameter (unlike {@link Collections#shuffle(List)})
     *
     * @param list The list to randomize
     * @param <T> The element type
     *
     * @return The randomized list
     */
    public<T> List<T> shuffle(List<T> list) {
        List<T> shuffled = new ArrayList<>(list);

        Collections.shuffle(shuffled, this);

        return shuffled;
    }

    /**
     * Create a new RandomUtil instance which is shared between instances (store in a static field)
     * This method allows the system to reset the random seed value when enable testing mode, for predictable random
     */
    static public RandomUtil createShared() {
        RandomUtil random = new RandomUtil();

        sharedInstances.add(random);

        return random;
    }

    /**
     * Enable the testing mode for get predictable random values
     * This method MUST NOT be used outside tests
     */
    static public void enableTestingMode() {
        testing = true;

        // Reset the random state
        sharedInstances.forEach(randomUtil -> randomUtil.setSeed(0));
    }
}


1		/*
2		* This file is part of ArakneUtils.
3		*
4		* ArakneUtils is free software: you can redistribute it and/or modify
5		* it under the terms of the GNU Lesser General Public License as published by
6		* the Free Software Foundation, either version 3 of the License, or
7		* (at your option) any later version.
8		*
9		* ArakneUtils is distributed in the hope that it will be useful,
10		* but WITHOUT ANY WARRANTY; without even the implied warranty of
11		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12		* GNU Lesser General Public License for more details.
13		*
14		* You should have received a copy of the GNU Lesser General Public License
15		* along with ArakneUtils. If not, see <https://www.gnu.org/licenses/>.
16		*
17		* Copyright (c) 2017-2020 Vincent Quatrevieux
18		*/
19
20		package fr.arakne.utils.value.helper;
21
22		import fr.arakne.utils.value.Interval;
23
24		import java.util.*;
25
26		/**
27		* Utility for random numbers
28		*
29		* This utility class must be used instead of the native {@link Random} class,
30		* for create predictable random values on testing environment
31		*
32		* It's not recommended to share the RandomUtil instance between objects instances (i.e. store into a static field)
33		* Each objects instance should have its own RandomUtil instance
34		* But in case of short-life objects static instance of RandomUtil can be used when created using {@link RandomUtil#createShared()}
35		*/
36		final public class RandomUtil extends Random {
37		/**
38		* Testing mode ?
39		* If set to true, the seed value will be fixed and random will be predictable
40		*/
41	1	static private boolean testing = false;
42
43		/**
44		* List of instance which are shared between instances
45		* This list is used for reset random seeds when enable testing mode
46		*
47		* @see RandomUtil#createShared()
48		*/
49	1	final static private Collection<RandomUtil> sharedInstances = new ArrayList<>();
50
51	1	public RandomUtil() {
52	1	if (testing) {
53	1	setSeed(0);
54		}
55	1	}
56
57		/**
58		* Get random number into [min, max] interval
59		* The interval is inclusive
60		*
61		* If max if lower than min, min is returned
62		*/
63		public int rand(int min, int max) {
64	1	if (max <= min) {
65	1	return min;
66		}
67
68	1	if (min == 0) {
69	1	return nextInt(max + 1);
70		}
71
72	1	return nextInt((max - min) + 1) + min;
73		}
74
75		/**
76		* Get random number into given interval
77		* The interval is inclusive
78		*/
79		public int rand(Interval interval) {
80	1	return rand(interval.min(), interval.max());
81		}
82
83		/**
84		* Get a random double between interval [0, max[
85		*
86		* @param max The maximum value (exclusive)
87		*/
88		public double decimal(double max) {
89	1	return nextDouble() * max;
90		}
91
92		/**
93		* Get a random number from an interval
94		*/
95		public int rand(int[] interval) {
96	1	if (interval.length == 1 \|\| interval[0] > interval[1]) {
97	1	return interval[0];
98		}
99
100	1	return rand(interval[0], interval[1]);
101		}
102
103		/**
104		* Get a random boolean value
105		*
106		* @param percent Percent of chance that the returned value is true.
107		* If the value is 100, this method will always returns true
108		* If the value is 0, the method will always returns false
109		*/
110		public boolean bool(int percent) {
111	1	return nextInt(100) < percent;
112		}
113
114		/**
115		* Get a random boolean value
116		* The returned value has same chance to be true or false
117		*
118		* This method is equivalent to `bool(50)`
119		*
120		* @see RandomUtil#bool(int)
121		*/
122		public boolean bool() {
123	1	return nextBoolean();
124		}
125
126		/**
127		* Get a random boolean value following reverse chance
128		* The return value if true with the probability of 1 / rate
129		* Higher the rate value is, lower the probability is
130		*
131		* For rate = 2, the probability is 50% and its equivalent to call bool(50) or bool()
132		* For rate = 100, the probability is 1% and its equivalent to call bool(1)
133		*
134		* @param rate The rate
135		*
136		* @return The random boolean value
137		*/
138		public boolean reverseBool(int rate) {
139	1	return nextInt(rate) == 0;
140		}
141
142		/**
143		* Get a random value from an array of values
144		* All elements has the same selection probability
145		*
146		* @param values The provided values
147		*
148		* @return One of the element of the array
149		*/
150		public<T> T of(T[] values) {
151	1	return values[nextInt(values.length)];
152		}
153
154		/**
155		* Get a random value from an array of characters
156		*
157		* @see RandomUtil#of(Object[])
158		*/
159		public char of(char[] values) {
160	1	return values[nextInt(values.length)];
161		}
162
163		/**
164		* Get a random value from a list of values
165		* All elements has the same selection probability
166		*
167		* @param values The provided values
168		*
169		* @return One of the element of the list
170		*/
171		public<T> T of(List<T> values) {
172	1	return values.get(nextInt(values.size()));
173		}
174
175		/**
176		* Randomize list element positions
177		* This method will create a copy of the list, without modify the input parameter (unlike {@link Collections#shuffle(List)})
178		*
179		* @param list The list to randomize
180		* @param <T> The element type
181		*
182		* @return The randomized list
183		*/
184		public<T> List<T> shuffle(List<T> list) {
185	1	List<T> shuffled = new ArrayList<>(list);
186
187	1	Collections.shuffle(shuffled, this);
188
189	1	return shuffled;
190		}
191
192		/**
193		* Create a new RandomUtil instance which is shared between instances (store in a static field)
194		* This method allows the system to reset the random seed value when enable testing mode, for predictable random
195		*/
196		static public RandomUtil createShared() {
197	1	RandomUtil random = new RandomUtil();
198
199	1	sharedInstances.add(random);
200
201	1	return random;
202		}
203
204		/**
205		* Enable the testing mode for get predictable random values
206		* This method MUST NOT be used outside tests
207		*/
208		static public void enableTestingMode() {
209	1	testing = true;
210
211		// Reset the random state
212	1	sharedInstances.forEach(randomUtil -> randomUtil.setSeed(0));
213	1	}
214		}
215

Arakne / ArakneUtils

Branch — master (27e47c)

createShared() A

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