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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  public interface TimestampOracle {
23  
24      void initialize() throws IOException;
25  
26      /**
27       * Returns the next timestamp if available. Otherwise spins till the
28       * ts-persist thread performs the new timestamp allocation
29       */
30      long next() throws IOException;
31  
32      long getLast();
33  
34  }