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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.committable;
19  
20  import com.google.common.base.Optional;
21  import com.google.common.util.concurrent.ListenableFuture;
22  
23  import java.io.Closeable;
24  import java.io.IOException;
25  
26  public interface CommitTable {
27  
28      long INVALID_TRANSACTION_MARKER = -1L;
29  
30      Writer getWriter() throws IOException;
31  
32      Client getClient() throws IOException;
33  
34      interface Writer extends Closeable {
35  
36          void addCommittedTransaction(long startTimestamp, long commitTimestamp) throws IOException;
37  
38          void updateLowWatermark(long lowWatermark) throws IOException;
39  
40          /**
41           * Flushes all the buffered events to the underlying datastore
42           */
43          void flush() throws IOException;
44  
45          /**
46           * Allows to clean the write's current buffer. It is required for HA
47           */
48          void clearWriteBuffer();
49  
50          /**
51           * Add commited transaction while checking if invalidated by other client
52           */
53          boolean atomicAddCommittedTransaction(long startTimestamp, long commitTimestamp) throws IOException;
54      }
55  
56      interface Client extends Closeable {
57  
58          /**
59           * Checks whether a transaction commit data is inside the commit table The function also checks whether the
60           * transaction was invalidated and returns a commit timestamp type accordingly.
61           *
62           * @param startTimestamp the transaction start timestamp
63           * @return Optional of CommitTimestamp that represents a valid, invalid, or no timestamp.
64           */
65          ListenableFuture<Optional<CommitTimestamp>> getCommitTimestamp(long startTimestamp);
66  
67          ListenableFuture<Long> readLowWatermark();
68  
69          ListenableFuture<Void> completeTransaction(long startTimestamp);
70  
71          /**
72           * Atomically tries to invalidate a non-committed transaction launched by a previous TSO server.
73           *
74           * @param startTimeStamp the transaction to invalidate
75           * @return true on success and false on failure
76           */
77          ListenableFuture<Boolean> tryInvalidateTransaction(long startTimeStamp);
78      }
79  
80      // ----------------------------------------------------------------------------------------------------------------
81      // Helper classes
82      // ----------------------------------------------------------------------------------------------------------------
83      class CommitTimestamp {
84  
85          public enum Location {
86              NOT_PRESENT, CACHE, COMMIT_TABLE, SHADOW_CELL
87          }
88  
89          private final Location location;
90          private final long value;
91          private final boolean isValid;
92  
93          public CommitTimestamp(Location location, long value, boolean isValid) {
94              this.location = location;
95              this.value = value;
96              this.isValid = isValid;
97          }
98  
99          public Location getLocation() {
100             return location;
101         }
102 
103         public long getValue() {
104             return value;
105         }
106 
107         public boolean isValid() {
108             return isValid;
109         }
110 
111         @Override
112         public String toString() {
113             return String.format("Is valid=%s, Location=%s, Value=%d)", isValid, location, value);
114         }
115 
116     }
117 
118 }