001    /*
002     * Copyright (c) 2007-2015 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.operation;
022    
023    import cascading.flow.FlowProcess;
024    
025    /**
026     * Interface Function marks a given {@link Operation} as a function, as opposed to being a {@link Filter}.
027     * <p/>
028     * A Function is responsible for taking Tuple arguments and returning one or more result Tuples.
029     * <p/>
030     * To implement a Function, (optionally) sub-class {@link BaseOperation} and have the new sub-class {@code implement}
031     * this interface.
032     */
033    public interface Function<Context> extends Operation<Context>
034      {
035      /**
036       * Method operate provides the implementation of this Function.
037       *
038       * @param flowProcess  of type FlowProcess
039       * @param functionCall of type FunctionCall
040       */
041      void operate( FlowProcess flowProcess, FunctionCall<Context> functionCall );
042      }