public Integer getPartition() {
    String changelogPartition = getMessageValue(CHANGELOG_VALUE_KEY);
    return StringUtils.isNotBlank(changelogPartition) ? Integer.parseInt(changelogPartition) : null;
  }
The change log mapping message is used to store changelog partition information for a given task name.
@param source Source writing the change log mapping
@param taskName The task name to be used in the mapping
@param changelogPartitionNumber The partition to which the task's changelog is mapped to
samza-core/src/main/java/org/apache/samza/coordinator/stream/messages/SetChangelogMapping.java