    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      }