org.dcache.resilience.util.RandomSelectionStrategy.java Source code

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Here is the source code for org.dcache.resilience.util.RandomSelectionStrategy.java

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/*
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package org.dcache.resilience.util;

import com.google.common.collect.Iterables;

import java.security.SecureRandom;
import java.util.Collection;
import java.util.function.Function;

/**
 *  <p>A simple utility for selection of a string. Chooses randomly from the
 *          elements in the collection.  Note that this does not side-effect
 *          the collection itself.</p>
 */
public final class RandomSelectionStrategy implements Function<Collection<String>, String> {

    public static final RandomSelectionStrategy SELECTOR = new RandomSelectionStrategy();

    private SecureRandom random = new SecureRandom();

    private RandomSelectionStrategy() {
    }

    @Override
    public String apply(Collection<String> collection) {
        if (collection.isEmpty()) {
            return null;
        }

        return Iterables.get(collection, random.nextInt(collection.size()));
    }
}