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.tuple.Fields;
024    import cascading.tuple.TupleEntry;
025    import cascading.tuple.TupleEntryCollector;
026    
027    /** Interface FunctionCall provides access to the current {@link Function} invocation arguments. */
028    public interface FunctionCall<C> extends OperationCall<C>
029      {
030      /**
031       * Returns {@link TupleEntry} of argument values.
032       * <p/>
033       * Note that the returned TupleEntry should not be cached (stored in a Collection), nor should the underlying Tuple
034       * instance. Where possible Cascading will re-use both TupleEntry and Tuple instances.
035       * <p/>
036       * To get a safe copy that can be cached, use {@link TupleEntry#getTupleCopy()}.
037       *
038       * @return TupleEntry
039       */
040      TupleEntry getArguments();
041    
042      /**
043       * Return the resolved {@link Fields} declared by the current {@link Operation}.
044       *
045       * @return Fields
046       */
047      Fields getDeclaredFields();
048    
049      /**
050       * Returns the {@link cascading.tuple.TupleEntryCollector} used to emit result values.
051       *
052       * @return TupleCollector
053       */
054      TupleEntryCollector getOutputCollector();
055      }