/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
**********************************************************************************************************************/
package eu.stratosphere.compiler.dataproperties;
/**
* An enumeration tracking the different types of sharding strategies.
*/
public enum PartitioningProperty {
/**
* Constant indicating no particular partitioning (i.e. random) data distribution.
*/
RANDOM,
/**
* Constant indicating a hash partitioning.
*/
HASH_PARTITIONED,
/**
* Constant indicating a range partitioning.
*/
RANGE_PARTITIONED,
/**
* Constant indicating any not further specified disjunct partitioning.
*/
ANY_PARTITIONING,
/**
* Constant indicating full replication of the data to each parallel instance.
*/
FULL_REPLICATION;
/**
* Checks, if this property represents in fact a partitioning. That is,
* whether this property is not equal to <tt>PartitionProperty.FULL_REPLICATION</tt>.
*
* @return True, if this enum constant is unequal to <tt>PartitionProperty.FULL_REPLICATION</tt>,
* false otherwise.
*/
public boolean isPartitioned() {
return this != FULL_REPLICATION;
}
/**
* Checks, if this property represents a full replication.
*
* @return True, if this enum constant is equal to <tt>PartitionProperty.FULL_REPLICATION</tt>,
* false otherwise.
*/
public boolean isReplication() {
return this == FULL_REPLICATION;
}
/**
* Checks if this property presents a partitioning that is not random, but on a partitioning key.
*
* @return True, if the data is partitioned on a key.
*/
public boolean isPartitionedOnKey() {
return isPartitioned() && this != RANDOM;
}
/**
* Checks, if this property represents a partitioning that is computable.
* Computable partitionings can be recreated through an algorithm. If two sets of data are to
* be co-partitioned, it is crucial, that the partitioning schemes are computable.
* <p>
* Examples for computable partitioning schemes are hash- or range-partitionings. An example for a non-computable
* partitioning is the implicit partitioning that exists though a globally unique key.
*
* @return True, if this enum constant is a re-computable partitioning.
*/
public boolean isComputablyPartitioned() {
return this == HASH_PARTITIONED || this == RANGE_PARTITIONED;
}
}