PlotSquared/Core/src/main/java/com/plotsquared/core/collection/FlatRandomCollection.java

67 lines
2.3 KiB
Java

/*
* PlotSquared, a land and world management plugin for Minecraft.
* Copyright (C) IntellectualSites <https://intellectualsites.com>
* Copyright (C) IntellectualSites team and contributors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package com.plotsquared.core.collection;
import com.plotsquared.core.util.MathMan;
import java.util.ArrayList;
import java.util.Map;
import java.util.Random;
public class FlatRandomCollection<T> extends RandomCollection<T> {
private final T[] values;
@SuppressWarnings("unchecked")
public FlatRandomCollection(Map<T, Double> weights, Random random) {
super(weights, random);
int max = 0;
int[] counts = new int[weights.size()];
Double[] weightDoubles = weights.values().toArray(new Double[0]);
for (int i = 0; i < weightDoubles.length; i++) {
int weight = (int) (weightDoubles[i] * 100);
counts[i] = weight;
if (weight != (weightDoubles[i] * 100)) {
throw new IllegalArgumentException("Too small");
}
if (weight > max) {
max = weight;
}
}
int gcd = MathMan.gcd(counts);
if (max / gcd > 100000) {
throw new IllegalArgumentException("Too large");
}
ArrayList<T> parsed = new ArrayList<>();
for (Map.Entry<T, Double> entry : weights.entrySet()) {
int num = (int) (100 * entry.getValue());
for (int j = 0; j < num / gcd; j++) {
parsed.add(entry.getKey());
}
}
this.values = (T[]) parsed.toArray();
}
@Override
public T next() {
return values[random.nextInt(values.length)];
}
}