/*
* Copyright © 2015-2016 Cask Data, Inc.
*
* 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 co.cask.cdap.api.dataset.lib.partitioned;
import co.cask.cdap.api.annotation.Beta;
import co.cask.cdap.api.dataset.lib.PartitionDetail;
/**
* Defines whether to accept {@link PartitionDetail}s, while iterating over a collection of them.
*/
@Beta
public interface PartitionAcceptor {
/**
* Return value, determining what to do with a Partition.
*/
enum Return {
/**
* Accept the partition.
*/
ACCEPT,
/**
* Skip over the partition. The skipped partition will remain as-is.
*/
SKIP,
/**
* Will not include the partition. Additionally, the iteration over the partitions will end.
*/
STOP
}
Return accept(PartitionDetail partitionDetail);
/**
* An implementation of PartitionAcceptor which limits the number of accepted partitions to a given value.
*/
final class Limit implements PartitionAcceptor {
private int count = 0;
private int limit;
public Limit(int limit) {
this.limit = limit;
}
@Override
public Return accept(PartitionDetail partitionDetail) {
if (count++ < limit) {
return Return.ACCEPT;
}
return Return.STOP;
}
}
}