77 lines
1.9 KiB
Java
77 lines
1.9 KiB
Java
package net.minecraft.util;
|
|
|
|
import java.util.List;
|
|
import java.util.Random;
|
|
|
|
public class WeightedRandom
|
|
{
|
|
/**
|
|
* Returns the total weight of all items in a collection.
|
|
*/
|
|
public static int getTotalWeight(List <? extends WeightedRandom.Item > collection)
|
|
{
|
|
int i = 0;
|
|
int j = 0;
|
|
|
|
for (int k = collection.size(); j < k; ++j)
|
|
{
|
|
WeightedRandom.Item weightedrandom$item = collection.get(j);
|
|
i += weightedrandom$item.itemWeight;
|
|
}
|
|
|
|
return i;
|
|
}
|
|
|
|
/**
|
|
* Returns a random choice from the input items, with a total weight value.
|
|
*/
|
|
public static <T extends WeightedRandom.Item> T getRandomItem(Random random, List<T> collection, int totalWeight)
|
|
{
|
|
if (totalWeight <= 0)
|
|
{
|
|
throw new IllegalArgumentException();
|
|
}
|
|
else
|
|
{
|
|
int i = random.nextInt(totalWeight);
|
|
return (T)getRandomItem(collection, i);
|
|
}
|
|
}
|
|
|
|
public static <T extends WeightedRandom.Item> T getRandomItem(List<T> collection, int weight)
|
|
{
|
|
int i = 0;
|
|
|
|
for (int j = collection.size(); i < j; ++i)
|
|
{
|
|
T t = collection.get(i);
|
|
weight -= t.itemWeight;
|
|
|
|
if (weight < 0)
|
|
{
|
|
return t;
|
|
}
|
|
}
|
|
|
|
return (T)null;
|
|
}
|
|
|
|
/**
|
|
* Returns a random choice from the input items.
|
|
*/
|
|
public static <T extends WeightedRandom.Item> T getRandomItem(Random random, List<T> collection)
|
|
{
|
|
return (T)getRandomItem(random, collection, getTotalWeight(collection));
|
|
}
|
|
|
|
public static class Item
|
|
{
|
|
/** The Weight is how often the item is chosen(higher number is higher chance(lower is lower)) */
|
|
public int itemWeight;
|
|
|
|
public Item(int itemWeightIn)
|
|
{
|
|
this.itemWeight = itemWeightIn;
|
|
}
|
|
}
|
|
} |