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.operation;
022
023import cascading.tuple.Fields;
024import cascading.tuple.TupleEntry;
025import cascading.tuple.TupleEntryCollector;
026
027/** Interface FunctionCall provides access to the current {@link Function} invocation arguments. */
028public 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  }