accord-core/src/test/java/accord/impl/TopologyUtils.java

package accord.impl;

import accord.api.Key;
import accord.api.KeyRange;
import accord.local.Node;
import accord.topology.KeyRanges;
import accord.topology.Shard;
import accord.topology.Shards;
import accord.utils.WrapAroundList;
import accord.utils.WrapAroundSet;

import java.util.*;

public class TopologyUtils
{
    public static KeyRanges initialRanges(int num, int maxKey)
    {
        int rangeSize = maxKey / num;
        KeyRange<IntKey>[] ranges = new KeyRange[num];
        int end = 0;
        for (int i=0; i<num; i++)
        {
            int start = end;
            end = i == num - 1 ? maxKey : start + rangeSize;
            ranges[i] = IntKey.range(start, end);
        }
        return new KeyRanges(ranges);
    }

    public static <K extends Key<K>> Shards initialTopology(Node.Id[] cluster, KeyRanges ranges, int rf)
    {
        final Map<Node.Id, Integer> lookup = new HashMap<>();
        for (int i = 0 ; i < cluster.length ; ++i)
            lookup.put(cluster[i], i);

        List<WrapAroundList<Node.Id>> electorates = new ArrayList<>();
        List<Set<Node.Id>> fastPathElectorates = new ArrayList<>();

        for (int i = 0 ; i < cluster.length + rf - 1 ; ++i)
        {
            WrapAroundList<Node.Id> electorate = new WrapAroundList<>(cluster, i % cluster.length, (i + rf) % cluster.length);
            Set<Node.Id> fastPathElectorate = new WrapAroundSet<>(lookup, electorate);
            electorates.add(electorate);
            fastPathElectorates.add(fastPathElectorate);
        }

        final List<Shard> shards = new ArrayList<>();
        for (int i = 0 ; i < ranges.size() ; ++i)
            shards.add(new Shard(ranges.get(i), electorates.get(i % electorates.size()), fastPathElectorates.get(i % fastPathElectorates.size())));
        return new Shards(shards.toArray(Shard[]::new));
    }

    public static <K extends Key<K>> Shards initialTopology(List<Node.Id> cluster, KeyRanges ranges, int rf)
    {
        return initialTopology(cluster.toArray(Node.Id[]::new), ranges, rf);
    }
}