Method getTokenRangesForHost

lib/metadata/index.js:355–381

* Gets the token ranges that are replicated on the given host, for * the given keyspace. * * @param {String} keyspaceName The name of the keyspace to get ranges for. * @param {Host} host The host. * @returns {Set |null} Ranges for the keyspace on this host or null if keyspa

(keyspaceName, host)

   * @returns {Set<TokenRange>|null} Ranges for the keyspace on this host or null if keyspace isn't found or hasn't been loaded.
   */
  getTokenRangesForHost(keyspaceName, host) {
    if (!this.ring) {
      return null;
    }
    let keyspace;
    if (keyspaceName) {
      keyspace = this.keyspaces[keyspaceName];
      if (!keyspace) {
        // the keyspace was not found, the metadata should be loaded beforehand
        return null;
      }
    }
    // If the ring has only 1 token, just return the ranges as we should only have a single node cluster.
    if (this.ring.length === 1) {
      return this.getTokenRanges();
    }
    const replicas = this._getKeyspaceReplicas(keyspace);
    const ranges = new Set();
    // for each range, find replicas for end token, if replicas include host, add range.
    this.tokenRanges.forEach((tokenRange) => {
      const replicasForToken = replicas[this.tokenizer.stringify(tokenRange.end)];
      if (replicasForToken.indexOf(host) !== -1) {
        ranges.add(tokenRange);
      }
    });
    return ranges;
  }

  /**
   * Constructs a Token from the input buffer(s) or string input.  If a string is passed in