bbbddebb16ba1b9a8261846c7fb2ae8d5bde17ef
[samza.git] / samza-api / src / main / java / org / apache / samza / operators / functions / FlatMapFunction.java
1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.samza.operators.functions;
20
21 import org.apache.samza.annotation.InterfaceStability;
22
23 import java.util.Collection;
24
25
26 /**
27 * A function that transforms an input message into a collection of 0 or more messages,
28 * possibly of a different type.
29 * @param <M> type of the input message
30 * @param <OM> type of the transformed messages
31 */
32 @InterfaceStability.Unstable
33 @FunctionalInterface
34 public interface FlatMapFunction<M, OM> extends InitableFunction {
35
36 /**
37 * Transforms the provided message into a collection of 0 or more messages.
38 * @param message the input message to be transformed
39 * @return a collection of 0 or more transformed messages
40 */
41 Collection<OM> apply(M message);
42
43 }