Request


1   /**
2    * Sequoia: Database clustering technology.
3    * Copyright (C) 2005 Continuent, Inc.
4    * Contact: sequoia@continuent.org
5    * 
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * 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   * Initial developer(s): Emmanuel Cecchet.
19   * Contributor(s): ______________________.
20   */
21  
22  package org.continuent.sequoia.common.sql;
23  
24  import java.io.IOException  ;
25  
26  import org.continuent.sequoia.common.stream.DriverBufferedInputStream;
27  import org.continuent.sequoia.common.stream.DriverBufferedOutputStream;
28  
29  /**
30   * This class defines a Request object. This basically carries the SQL statement
31   * and the SQL template if this is a PreparedStatement.
32   * 
33   * @author <a HREF="mailto:emmanuel.cecchet@continuent.com">Emmanuel Cecchet</a>
34   * @version 1.0
35   */
36  public class Request
37  {
38    /**
39     * SQL query if this is a statement (should be set in constructor) or query
40     * template if this is a PreparedStatement.
41     */
42    private String    sqlQueryOrTemplate;
43  
44    /**
45     * PreparedStatement parameters
46     */
47    private String    preparedStatementParameters = null;
48  
49    //
50    // Connection related parameters
51    //
52  
53    /** True if the connection has been set to read-only */
54    private boolean isReadOnly                  = false;
55  
56    /**
57     * Whether this request has been sent in <code>autocommit</code> mode or
58     * not.
59     */
60    private boolean isAutoCommit                = true;
61  
62    /**
63     * Transaction isolation level to use when executing the query inside a
64     * transaction. The value is set by the VirtualDatabaseWorkerThread.
65     */
66    private int     transactionIsolation;
67  
68    /**
69     * Timeout for this request in seconds, value 0 means no timeout (should be
70     * set in constructor). This timeout is in seconds, reflecting the jdbc-spec,
71     * and is passed as-is to the backends jdbc-driver. Internally converted to ms
72     * via getTimeoutMs().
73     */
74    private int     timeoutInSeconds;
75  
76    /**
77     * Should the backend driver do escape processing before sending to the
78     * database? Simply forwarded to backend driver. No setter for this member,
79     * should be set in constructor.
80     * 
81     * @see java.sql.Statement#setEscapeProcessing(boolean)
82     */
83    private boolean escapeProcessing            = true;
84  
85    /**
86     * Request identifier only used for failover purposes. This id is sent back by
87     * the controller.
88     */
89    private long    id;
90  
91    //
92    // Constructors
93    //
94  
95    /**
96     * Creates a new <code>Request</code> object
97     * 
98     * @param sqlTemplate the SQL template (using ? as parameter placeholders) or
99     *          null
100    * @param parameters the prepared statement parameters
101    * @param escapeProcessing Should the backend driver do escape processing
102    *          before sending to the database?
103    * @param timeoutInSeconds Timeout for this request in seconds, value 0 means
104    *          no timeout
105    */
106   public Request(String   sqlTemplate, String   parameters,
107       boolean escapeProcessing, int timeoutInSeconds)
108   {
109     this.sqlQueryOrTemplate = sqlTemplate;
110     this.preparedStatementParameters = parameters;
111     this.escapeProcessing = escapeProcessing;
112     this.timeoutInSeconds = timeoutInSeconds;
113   }
114 
115   //
116   // Serialization
117   //
118 
119   /**
120    * Creates a new <code>Request</code> object, deserializing it from an input
121    * stream. Has to mirror the serialization method below.
122    * 
123    * @param in the input stream to read from
124    * @throws IOException if a network error occurs
125    */
126 
127   public Request(DriverBufferedInputStream in) throws IOException  
128   {
129     this.sqlQueryOrTemplate = in.readLongUTF();
130     this.escapeProcessing = in.readBoolean();
131     this.timeoutInSeconds = in.readInt();
132 
133     this.isAutoCommit = in.readBoolean();
134 
135     // Does this request has a template with question marks "?"
136     // true for PreparedStatements
137     // (AND did we ask for them at connection time?)
138     if (in.readBoolean())
139       this.preparedStatementParameters = in.readLongUTF();
140 
141     // success, we received it all
142   }
143 
144   /**
145    * Serialize the request on the output stream by sending only the needed
146    * parameters to reconstruct it on the controller. Has to mirror the
147    * deserialization method above.
148    * 
149    * @param out destination DriverBufferedOutputStream
150    * @throws IOException if fails
151    */
152 
153   public void sendToStream(DriverBufferedOutputStream out) throws IOException  
154   {
155     out.writeLongUTF(sqlQueryOrTemplate);
156     out.writeBoolean(escapeProcessing);
157     out.writeInt(timeoutInSeconds);
158 
159     out.writeBoolean(isAutoCommit);
160 
161     // Send the "un-"PreparedStatement if the controller wants it:
162     // - either for better parsing
163     // - or to process it
164     // - && this is a PreparedStatement (of course)
165     if (preparedStatementParameters != null)
166     {
167       out.writeBoolean(true);
168       out.writeLongUTF(preparedStatementParameters);
169     }
170     else
171       out.writeBoolean(false);
172   }
173 
174   //
175   // Getters/Setters
176   //
177 
178   /**
179    * Returns the escapeProcessing value.
180    * 
181    * @return Returns the escapeProcessing.
182    */
183   public final boolean isEscapeProcessing()
184   {
185     return escapeProcessing;
186   }
187 
188   /**
189    * Sets the escapeProcessing value.
190    * 
191    * @param escapeProcessing The escapeProcessing to set.
192    */
193   public final void setEscapeProcessing(boolean escapeProcessing)
194   {
195     this.escapeProcessing = escapeProcessing;
196   }
197 
198   /**
199    * Returns the isAutoCommit value.
200    * 
201    * @return Returns the isAutoCommit.
202    */
203   public final boolean isAutoCommit()
204   {
205     return isAutoCommit;
206   }
207 
208   /**
209    * Sets the isAutoCommit value.
210    * 
211    * @param isAutoCommit The isAutoCommit to set.
212    */
213   public final void setIsAutoCommit(boolean isAutoCommit)
214   {
215     this.isAutoCommit = isAutoCommit;
216   }
217 
218   /**
219    * Returns the isReadOnly value.
220    * 
221    * @return Returns the isReadOnly.
222    */
223   public final boolean isReadOnly()
224   {
225     return isReadOnly;
226   }
227 
228   /**
229    * Sets the isReadOnly value.
230    * 
231    * @param isReadOnly The isReadOnly to set.
232    */
233   public final void setIsReadOnly(boolean isReadOnly)
234   {
235     this.isReadOnly = isReadOnly;
236   }
237 
238   /**
239    * Returns the id value.
240    * 
241    * @return Returns the id.
242    */
243   public long getId()
244   {
245     return id;
246   }
247 
248   /**
249    * Sets the id value.
250    * 
251    * @param id The id to set.
252    */
253   public void setId(long id)
254   {
255     this.id = id;
256   }
257 
258   /**
259    * Returns the sqlQuery value.
260    * 
261    * @return Returns the sqlQuery.
262    */
263   public final String   getSqlQueryOrTemplate()
264   {
265     return sqlQueryOrTemplate;
266   }
267 
268   /**
269    * Get a short form of this request if the SQL statement exceeds
270    * nbOfCharacters.
271    * 
272    * @param nbOfCharacters number of characters to include in the short form.
273    * @return the nbOfCharacters first characters of the SQL statement
274    */
275   public String   getSqlShortForm(int nbOfCharacters)
276   {
277     if ((nbOfCharacters == 0) || (sqlQueryOrTemplate.length() < nbOfCharacters))
278       return sqlQueryOrTemplate;
279     else
280       return sqlQueryOrTemplate.substring(0, nbOfCharacters) + "...";
281   }
282 
283   /**
284    * Returns the sqlTemplate value.
285    * 
286    * @return Returns the sqlTemplate.
287    */
288   public final String   getPreparedStatementParameters()
289   {
290     return preparedStatementParameters;
291   }
292 
293   /**
294    * Returns the timeoutInSeconds value.
295    * 
296    * @return Returns the timeoutInSeconds.
297    */
298   public final int getTimeoutInSeconds()
299   {
300     return timeoutInSeconds;
301   }
302 
303   /**
304    * Sets the timeoutInSeconds value.
305    * 
306    * @param timeoutInSeconds The timeoutInSeconds to set.
307    */
308   public final void setTimeoutInSeconds(int timeoutInSeconds)
309   {
310     this.timeoutInSeconds = timeoutInSeconds;
311   }
312 
313   /**
314    * Returns the transactionIsolation value.
315    * 
316    * @return Returns the transactionIsolation.
317    */
318   public final int getTransactionIsolation()
319   {
320     return transactionIsolation;
321   }
322 
323   /**
324    * Sets the transactionIsolation value.
325    * 
326    * @param transactionIsolation The transactionIsolation to set.
327    */
328   public final void setTransactionIsolation(int transactionIsolation)
329   {
330     this.transactionIsolation = transactionIsolation;
331   }
332 
333 }
334
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