143bae0861d322b9eb1f391b96430b7ea4be5b15
[samza.git] / samza-api / src / main / java / org / apache / samza / operators / functions / FilterFunction.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
24 /**
25 * A function that specifies whether a message should be retained for further processing or filtered out.
26 * @param <M> type of the input message
27 */
28 @InterfaceStability.Unstable
29 @FunctionalInterface
30 public interface FilterFunction<M> extends InitableFunction {
31
32 /**
33 * Returns a boolean indicating whether this message should be retained or filtered out.
34 * @param message the input message to be checked. This object should not be mutated.
35 * @return true if {@code message} should be retained
36 */
37 boolean apply(M message);
38
39 }