001    /*
002     * Copyright (c) 2007-2014 Concurrent, 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    
021    package cascading.tuple.collect;
022    
023    import java.util.Collection;
024    
025    import cascading.provider.CascadingFactory;
026    import cascading.tuple.Tuple;
027    
028    /**
029     * Interface TupleCollectionFactory allows developers to plugin alternative implementations of a "tuple collection"
030     * used to back in memory "join" and "co-group" operations. Typically these implementations are
031     * "spillable", in that to prevent using up all memory in the JVM, after some threshold is met or event
032     * is triggered, values are persisted to disk.
033     * <p/>
034     * The {@link java.util.Collection} classes returned must take a {@link cascading.tuple.Tuple} as a value.
035     * <p/>
036     * If the Collection implementation implements the {@link Spillable} interface, it will receive a {@link Spillable.SpillListener}
037     * instance that calls back to the appropriate logging mechanism for the platform.
038     * <p/>
039     * The class {@link SpillableTupleList} may be used as a base class.
040     *
041     * @see cascading.tuple.hadoop.collect.HadoopTupleCollectionFactory
042     * @see SpillableTupleList
043     * @see cascading.tuple.hadoop.collect.HadoopSpillableTupleList
044     * @see TupleMapFactory
045     * @see cascading.tuple.hadoop.collect.HadoopTupleMapFactory
046     */
047    public interface TupleCollectionFactory<Config> extends CascadingFactory<Config, Collection<Tuple>>
048      {
049      String TUPLE_COLLECTION_FACTORY = "cascading.factory.tuple.collection.classname";
050      }