io.lettuce.core.cluster.PartitionsConsensus Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of lettuce-core Show documentation

Advanced and thread-safe Java Redis client for synchronous, asynchronous, and reactive usage. Supports Cluster, Sentinel, Pipelining, Auto-Reconnect, Codecs and much more.

The newest version!

package io.lettuce.core.cluster;

import java.util.Map;

import io.lettuce.core.RedisURI;
import io.lettuce.core.cluster.models.partitions.Partitions;

/**
 * Consensus API to decide on the {@link io.lettuce.core.cluster.models.partitions.Partitions topology view} to be used by
 * {@link RedisClusterClient}.
 * 
 * {@link PartitionsConsensus} takes the current {@link Partitions} and a {@link java.util.Map} of newly retrieved
 * {@link Partitions} to determine a view that shall be used. Implementing classes may reuse {@link Partitions} from input
 * arguments or construct a new {@link Partitions} object.
 *
 * @author Mark Paluch
 * @since 4.2
 * @see io.lettuce.core.cluster.models.partitions.Partitions
 * @see RedisClusterClient
 */
abstract class PartitionsConsensus {

    /**
     * Consensus algorithm to select a partition containing the most previously known nodes.
     */
    public static final PartitionsConsensus KNOWN_MAJORITY = new PartitionsConsensusImpl.KnownMajority();

    /**
     * Consensus algorithm to select a topology view containing the most active nodes.
     */
    public static final PartitionsConsensus HEALTHY_MAJORITY = new PartitionsConsensusImpl.HealthyMajority();

    /**
     * Determine the {@link Partitions} to be used by {@link RedisClusterClient}.
     *
     * @param current the currently used topology view, must not be {@code null}.
     * @param topologyViews the newly retrieved views, must not be {@code null}.
     * @return the resulting {@link Partitions} to be used by {@link RedisClusterClient}.
     */
    abstract Partitions getPartitions(Partitions current, Map topologyViews);

}