001/* 002 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.tap.partition; 022 023import java.io.Serializable; 024 025import cascading.tuple.Fields; 026import cascading.tuple.TupleEntry; 027 028/** 029 * The Partition interface allows for custom partitioning mechanisms to be created with the {@link BasePartitionTap} 030 * sub-classes. 031 * <p/> 032 * A partition is a directory on a filesystem, where the directory contains data related to the files underneath 033 * the partition directory. 034 * <p/> 035 * For example, a partition could be {@code "2012/09/01"}, which would contain log files for that day. 036 */ 037public interface Partition extends Serializable 038 { 039 /** 040 * Returns the directory search depth of the partition. 041 * <p/> 042 * For example, a Partition implementation that returns values like {@code "2012/09/01"} would have a depth of 3. 043 * 044 * @return an int 045 */ 046 int getPathDepth(); 047 048 /** 049 * The {@link Fields} used to populate the partition. 050 * 051 * @return a Fields instance 052 */ 053 Fields getPartitionFields(); 054 055 /** 056 * Converts the given partition String to a {@link TupleEntry} using the given TupleEntry instance for re-use. 057 * 058 * @param partition a String 059 * @param tupleEntry a TupleEntry 060 */ 061 void toTuple( String partition, TupleEntry tupleEntry ); 062 063 /** 064 * Converts the given tupleEntry into a partition string. 065 * 066 * @param tupleEntry a TupleEntry 067 * @return a String 068 */ 069 String toPartition( TupleEntry tupleEntry ); 070 }