DatabaseBackendMBean


1   /**
2    * Sequoia: Database clustering technology.
3    * Copyright (C) 2002-2004 French National Institute For Research In Computer
4    * Science And Control (INRIA).
5    * Contact: sequoia@continuent.org
6    * 
7    * Licensed under the Apache License, Version 2.0 (the "License");
8    * you may not use this file except in compliance with the License.
9    * You may obtain a copy of the License at
10   * 
11   * http://www.apache.org/licenses/LICENSE-2.0
12   * 
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License. 
18   *
19   * Initial developer(s): Nicolas Modrzyk
20   * Contributor(s): 
21   */
22  
23  package org.continuent.sequoia.common.jmx.mbeans;
24  
25  import java.util.List  ;
26  
27  /**
28   * MBeanInterface to the DatabaseBackend
29   * 
30   * @author <a HREF="mailto:Nicolas.Modrzyk@inrialpes.fr">Nicolas Modrzyk </a>
31   * @version 1.0
32   */
33  public interface DatabaseBackendMBean
34  {
35    /**
36     * Tests if this backend is enabled (active and synchronized).
37     * 
38     * @return <code>true</code> if this backend is enabled
39     * @throws Exception if an error occurs
40     */
41    boolean isInitialized() throws Exception  ;
42  
43    /**
44     * Tests if this backend is read enabled (active and synchronized).
45     * 
46     * @return <code>true</code> if this backend is enabled.
47     */
48    boolean isReadEnabled();
49  
50    /**
51     * Tests if this backend is write enabled (active and synchronized).
52     * 
53     * @return <code>true</code> if this backend is enabled.
54     */
55    boolean isWriteEnabled();
56  
57    /**
58     * Is the backend completely disabled ? This usually means it has a known
59     * state with a checkpoint associated to it.
60     * 
61     * @return <code>true</code> if the backend is disabled
62     */
63    boolean isDisabled();
64  
65    /**
66     * Enables the database backend for reads. This method should only be called
67     * when the backend is synchronized with the others.
68     */
69    void enableRead();
70  
71    /**
72     * Enables the database backend for writes. This method should only be called
73     * when the backend is synchronized with the others.
74     */
75    void enableWrite();
76  
77    /**
78     * Disables the database backend for reads. This does not affect write ability
79     */
80    void disableRead();
81  
82    /**
83     * Disables the database backend for writes. This does not affect read ability
84     * although the backend will not be coherent anymore as soon as a write as
85     * occured. This should be used in conjunction with a checkpoint to recover
86     * missing writes.
87     */
88    void disableWrite();
89  
90    /**
91     * Sets the database backend state to disable. This state is just an
92     * indication and it has no semantic effect. It is up to the request manager
93     * (especially the load balancer) to ensure that no more requests are sent to
94     * this backend.
95     */
96    void disable();
97  
98    /**
99     * Returns the SQL statement to use to check the connection validity.
100    * 
101    * @return a <code>String</code> containing a SQL statement
102    */
103   String   getConnectionTestStatement();
104 
105   /**
106    * Returns the database native JDBC driver class name.
107    * 
108    * @return the driver class name
109    */
110   String   getDriverClassName();
111 
112   /**
113    * Returns the backend logical name.
114    * 
115    * @return the backend logical name
116    */
117   String   getName();
118 
119   /**
120    * Returns a description of the state of the backend
121    * 
122    * @see org.continuent.sequoia.common.jmx.notifications.SequoiaNotificationList
123    * @return a string description of the state. Can be enabled, disabled,
124    *         recovering, backuping ...
125    */
126   String   getState();
127 
128   /**
129    * Return the integer value corresponding to the state of the backend. The
130    * values are defined in <code>BackendState</code>
131    * 
132    * @return <tt>int</tt> value
133    * @see org.continuent.sequoia.common.jmx.management.BackendState
134    */
135   int getStateValue();
136 
137   /**
138    * Returns the list of pending requests for this backend.
139    * 
140    * @param count number of requests to retrieve, if 0, return all.
141    * @param fromFirst count the request from first if true, or from last if
142    *          false
143    * @param clone should clone the pending request if true, block it if false
144    * @return <code>List</code> of <code>String</code> description of each
145    *         request.
146    */
147   List   getPendingRequestsDescription(int count, boolean fromFirst, boolean clone);
148 
149   /**
150    * Returns the list of active transactions for this backend.
151    * 
152    * @return <code>List</code> of <code>Long</code>, corresponding to
153    *         active transaction identifier.
154    */
155   List   getActiveTransactions();
156 
157   /**
158    * Gets the names of the tables. <b>NOTE</b>: The returned array will contain
159    * only one entry per actual table prefixed by the schema name + "."
160    * 
161    * @return the names as an array of <code>Strings</code>, or an empty array
162    *         if no tables were found
163    */
164   String  [] getTablesNames();
165 
166   /**
167    * Gets the names of the columns.
168    * 
169    * @param tableName fully qualified name of the table (with
170    *          <code><schema>.</code> prefix)
171    * @return an array containing the columns names, or null if tableName is not
172    *         a valid table name.
173    */
174   String  [] getColumnsNames(String   tableName);
175 
176   /**
177    * Gets a description of the given table locks.
178    * 
179    * @param tableName fully qualified name of the table (with
180    *          <code><schema>.</code> prefix)
181    * @return a (localized) string containing either "No locks" or "Locked by
182    *         <tid>"
183    */
184   String   getLockInfo(String   tableName);
185 
186   /**
187    * Lists all stored procedures in this schema. <b>Note:</b> There is an issue
188    * with stored procedures with same name (but different parameters): one will
189    * appear with 0 parameters, the 2nd with the total parameters from the 2
190    * stored proc. See SEQUOIA-296 for more info
191    * 
192    * @return An array of Strings containing all stored procedure names (one
193    *         array entry per procedure)
194    */
195   String  [] getStoredProceduresNames();
196 
197   /**
198    * Returns the JDBC URL used to access the database.
199    * 
200    * @return a JDBC URL
201    */
202   String   getURL();
203 
204   /**
205    * Returns the driver path.
206    * 
207    * @return the driver path
208    */
209   String   getDriverPath();
210 
211   /**
212    * Returns the lastKnownCheckpoint value.
213    * 
214    * @return Returns the lastKnownCheckpoint.
215    */
216   String   getLastKnownCheckpoint();
217 
218   /**
219    * Is the backend accessible ?
220    * 
221    * @return <tt>true</tt> if a jdbc connection is still possible from the
222    *         controller, <tt>false</tt> if connectionTestStatement failed
223    */
224   boolean isJDBCConnected();
225 
226   /**
227    * Return a string description of the backend in xml format. This does not
228    * include the schema description if the dynamic precision is not set to
229    * static.
230    * 
231    * @return an xml formatted string
232    */
233   String   getXml();
234 }
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