BackendDriverException


1   /**
2    * C-JDBC: Clustered JDBC.
3    * Copyright (C) 2005 Emic Networks
4    * Contact: c-jdbc@objectweb.org
5    * 
6    * This library is free software; you can redistribute it and/or modify it
7    * under the terms of the GNU Lesser General Public License as published by the
8    * Free Software Foundation; either version 2.1 of the License, or any later
9    * version.
10   * 
11   * This library is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
14   * for more details.
15   * 
16   * You should have received a copy of the GNU Lesser General Public License
17   * along with this library; if not, write to the Free Software Foundation,
18   * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
19   *
20   * Initial developer(s): Marc Herbert
21   * Contributor(s): ______________________.
22   */
23  
24  package org.objectweb.cjdbc.common.exceptions.driver.protocol;
25  
26  import java.io.IOException  ;
27  import java.sql.SQLException  ;
28  
29  import org.objectweb.cjdbc.common.stream.CJDBCInputStream;
30  
31  /**
32   * This class is an SQLException (typically from backend) made serializable.
33   * 
34   * @author <a HREF="mailto:Marc.Herbert@emicnetworks.com">Marc Herbert</a>
35   * @version 1.0
36   */
37  public class BackendDriverException
38      extends SerializableException
39  {
40    /**
41     * @see SerializableException#SerializableException(CJDBCInputStream)
42     */
43    public BackendDriverException(CJDBCInputStream in) throws IOException  
44    {
45      super(in);
46    }
47  
48    /**
49     * Converts a chain of Throwables to a new chain of SerializableException
50     * starting with a <code>BackendDriverException</code>. The returned chain
51     * has the same length. We don't use super's method but re-implement it since
52     * we want to also convert SQLException old-style chaining into a new style
53     * chain. "SyntheticSQLException-s" from
54     * {@link org.objectweb.cjdbc.common.exceptions.SQLExceptionFactory} also
55     * currently use old style chaining (with setNextException).
56     * 
57     * @param start head of chain to convert.
58     * @see SerializableException#SerializableException(Throwable)
59     */
60    public BackendDriverException(Throwable   start)
61    {
62      super(start.getMessage(), convertNext(start)); // recursion here
63      convertStackTrace(start);
64  
65      if (start instanceof SQLException  ) // hopefully, else why are we here?
66      {
67        SQLException   sqlE = (SQLException  ) start;
68        setSQLState(sqlE.getSQLState());
69        setErrorCode(sqlE.getErrorCode());
70      }
71    }
72  
73    /**
74     * Get the first cause found (new or old style), and convert it to a new
75     * BackendDriverException object (which is Serializable)
76     */
77  
78    private static SerializableException convertNext(Throwable   regularEx)
79    {
80      /*
81       * If we find that the new standard 1.4 chain is used, then we don't even
82       * look at the old SQLException chain.
83       */
84      /*
85       * We could also <em>not</em> lose this information by: adding another
86       * separated chain to this class, serialize both chains, and convert
87       * everything back to SQLExceptions on the driver side so both chains can
88       * separately be offered to the JDBC client...
89       */
90      Throwable   newStyleCause = regularEx.getCause();
91      if (null != newStyleCause)
92        return new BackendDriverException(newStyleCause);
93  
94      // check legacy style chaining
95      if (regularEx instanceof SQLException  )
96      {
97        SQLException   nextE = ((SQLException  ) regularEx).getNextException();
98        if (null != nextE)
99          return new BackendDriverException(nextE);
100     }
101 
102     // found no more link, stop condition
103     return null;
104 
105   }
106 }
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