com.bazaarvoice.emodb.sor.condition.PartitionCondition Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of emodb-sor-api Show documentation

The newest version!

package com.bazaarvoice.emodb.sor.condition;

/**
 * Condition to explicitly partition the events based on a hash of the document ID.  The condition takes two parameters:
 *
 * 
 *     The total number of partitions
 *     A condition which tests whether the partition for the current document is a match
 * 
 *
 * For example, the following two conditions should roughly split all matching documents between them:
 *
 * 
 *     and({..,"type":"review"},partition(2:1))
 *     and({..,"type":"review"},partition(2:2))
 * 
 *
 * Note that partitions are 1-based and so for a number of partitions p the possible matching conditions
 * are the integers in [1..p].  There are some checks preventing the client from providing invalid
 * conditions but these are non-exhaustive and do not cover meaningless conditions.  For example, the following
 * conditions will result no matches:
 *
 * 
 *     partition(4: ge(5))
 *     partition(4: and(1,2))
 * 
 */
public interface PartitionCondition extends Condition {

    /**
     * Total number of partitions.  Must be a positive integer.
     */
    int getNumPartitions();

    /**
     * Condition to evaluate whether the partition for the current document matches.  Most commonly this will be
     * a simple equality condition such as eq(1) which can be shortened to just 1.
     */
    Condition getCondition();
}