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, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.omid.tso;
19
20 import java.io.IOException;
21
22 /**
23 * Functionality of a service delivering monotonic increasing timestamps.
24 */
25 public interface TimestampOracle {
26
27 /**
28 * Allows the initialization of the Timestamp Oracle service.
29 * @throws IOException
30 * raised if a problem during initialization is shown.
31 */
32 void initialize() throws IOException;
33
34 /**
35 * Returns the next timestamp.
36 */
37 long next();
38
39 /**
40 * Returns the last timestamp assigned.
41 */
42 long getLast();
43
44 }