AlterRequest


1   /**
2    * C-JDBC: Clustered JDBC.
3    * Copyright (C) 2002-2004 French National Institute For Research In Computer
4    * Science And Control (INRIA).
5    * Contact: c-jdbc@objectweb.org
6    * 
7    * This library is free software; you can redistribute it and/or modify it
8    * under the terms of the GNU Lesser General Public License as published by the
9    * Free Software Foundation; either version 2.1 of the License, or any later
10   * version.
11   * 
12   * This library is distributed in the hope that it will be useful, but WITHOUT
13   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14   * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
15   * for more details.
16   * 
17   * You should have received a copy of the GNU Lesser General Public License
18   * along with this library; if not, write to the Free Software Foundation,
19   * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20   *
21   * Initial developer(s): Nicolas Modrzyk.
22   * Contributor(s): ______________________.
23   */
24  
25  package org.objectweb.cjdbc.common.sql;
26  
27  import java.io.IOException  ;
28  import java.sql.SQLException  ;
29  import java.util.ArrayList  ;
30  
31  import org.objectweb.cjdbc.common.sql.schema.DatabaseColumn;
32  import org.objectweb.cjdbc.common.sql.schema.DatabaseSchema;
33  import org.objectweb.cjdbc.common.sql.schema.DatabaseTable;
34  import org.objectweb.cjdbc.common.sql.schema.TableColumn;
35  import org.objectweb.cjdbc.common.stream.CJDBCInputStream;
36  
37  /**
38   * This class defines a AlterRequest
39   * 
40   * @author <a HREF="mailto:Nicolas.Modrzyk@inrialpes.fr">Nicolas Modrzyk </a>
41   * @version 1.0
42   */
43  public class AlterRequest extends AbstractWriteRequest
44  {
45    private static final long        serialVersionUID = -6511969618172455539L;
46  
47    /** The table to alter. */
48    private transient DatabaseTable  table            = null;
49  
50    /** The column altered */
51    private transient DatabaseColumn column           = null;
52  
53    private transient boolean        isDrop           = false;
54    private transient boolean        isAdd            = false;
55  
56    /**
57     * Creates a new <code>AlterRequest</code> instance. The caller must give an
58     * SQL request, without any leading or trailing spaces and beginning with
59     * 'alter table '
60     * <p>
61     * The request is not parsed but it can be done later by a call to
62     * {@link #parse(DatabaseSchema, int, boolean)}.
63     * 
64     * @param sqlQuery the SQL request
65     * @param escapeProcessing should the driver to escape processing before
66     *          sending to the database ?
67     * @param timeout an <code>int</code> value
68     * @param lineSeparator the line separator used in the query
69     * @see #parse
70     */
71    public AlterRequest(String   sqlQuery, boolean escapeProcessing, int timeout,
72        String   lineSeparator)
73    {
74      super(sqlQuery, escapeProcessing, timeout, lineSeparator, RequestType.ALTER);
75    }
76  
77    /**
78     * Creates a new <code>AlterRequest</code> instance. The caller must give an
79     * SQL request, without any leading or trailing spaces and beginning with
80     * 'alter table '
81     * <p>
82     * If the syntax is incorrect an exception is thrown.
83     * 
84     * @param sqlQuery the SQL request
85     * @param escapeProcessing should the driver to escape processing before
86     *          sending to the database?
87     * @param timeout an <code>int</code> value
88     * @param lineSeparator the line separator used in the query
89     * @param schema a <code>DatabaseSchema</code> value
90     * @param granularity parsing granularity as defined in
91     *          <code>ParsingGranularities</code>
92     * @param isCaseSensitive true if parsing is case sensitive
93     * @exception SQLException if an error occurs
94     */
95    public AlterRequest(String   sqlQuery, boolean escapeProcessing, int timeout,
96        String   lineSeparator, DatabaseSchema schema, int granularity,
97        boolean isCaseSensitive) throws SQLException  
98    {
99      this(sqlQuery, escapeProcessing, timeout, lineSeparator);
100     parse(schema, granularity, isCaseSensitive);
101   }
102 
103   /**
104    * @see AbstractWriteRequest
105    */
106   public AlterRequest(CJDBCInputStream in) throws IOException  
107   {
108     super(in, RequestType.ALTER);
109   }
110 
111   /**
112    * @see org.objectweb.cjdbc.common.sql.AbstractRequest#needsMacroProcessing()
113    */
114   public boolean needsMacroProcessing()
115   {
116     return false;
117   }
118 
119   /**
120    * @see org.objectweb.cjdbc.common.sql.AbstractRequest#returnsResultSet()
121    */
122   public boolean returnsResultSet()
123   {
124     return false;
125   }
126 
127   /**
128    * @see org.objectweb.cjdbc.common.sql.AbstractRequest#parse(org.objectweb.cjdbc.common.sql.schema.DatabaseSchema,
129    *      int, boolean)
130    */
131   public void parse(DatabaseSchema schema, int granularity,
132       boolean isCaseSensitive) throws SQLException  
133   {
134     /*
135      * Example Alter statement: ALTER TABLE table_name ADD column_name datatype
136      * ALTER TABLE table_name DROP COLUMN column_name
137      */
138 
139     if (granularity == ParsingGranularities.NO_PARSING)
140     {
141       isParsed = true;
142       return;
143     }
144 
145     String   originalSQL = this.trimCarriageReturnAndTabs();
146     String   sql = originalSQL.toLowerCase();
147 
148     // Strip 'alter table '
149     int tableIdx = sql.indexOf("table");
150     if (tableIdx == -1)
151       throw new SQLException  (
152           "Malformed Alter Request. Should start with [ALTER TABLE]");
153     sql = sql.substring(tableIdx + 5).trim();
154 
155     // Does the query contain a add?
156     int addIdx = sql.indexOf(" add ");
157 
158     // Does the query contain a drop?
159     int dropIdx = sql.indexOf(" drop ");
160 
161     if (addIdx != -1)
162       isAdd = true;
163     if (dropIdx != -1)
164       isDrop = true;
165 
166     if (!isAdd && !isDrop)
167       throw new SQLException  (
168           "Malformed Alter Request. No drop or add condition");
169 
170     if (isCaseSensitive) // Reverse to the original case
171       sql = originalSQL.substring(originalSQL.length() - sql.length());
172 
173     int index = (isAdd) ? addIdx : dropIdx;
174 
175     tableName = sql.substring(0, index).trim();
176     table = new DatabaseTable(tableName);
177 
178     if (granularity > ParsingGranularities.TABLE)
179     {
180 
181       int subsIndex = index + 6 + 2; // index +
182       // column.length()
183       // + space
184       if (isAdd)
185         subsIndex += 3;
186       else
187         // Drop
188         subsIndex += 4;
189 
190       columns = new ArrayList  ();
191       sql = sql.substring(subsIndex).trim();
192 
193       if (isAdd)
194       {
195         int colIndex = sql.indexOf(' ');
196         String   colName = sql.substring(0, colIndex);
197 
198         int uniqueIndex = sql.toLowerCase().indexOf("unique");
199         int primary = sql.toLowerCase().indexOf("primary");
200         if (uniqueIndex != -1 || primary != -1)
201           column = new DatabaseColumn(colName, true);
202         else
203           column = new DatabaseColumn(colName, false);
204         columns.add(new TableColumn(tableName, colName));
205       }
206       else if (isDrop)
207       {
208         String   colName = sql.trim();
209         column = schema.getTable(tableName).getColumn(colName);
210         columns.add(new TableColumn(tableName, colName));
211       }
212     }
213     isParsed = true;
214   }
215 
216   /**
217    * @see org.objectweb.cjdbc.common.sql.AbstractRequest#cloneParsing(org.objectweb.cjdbc.common.sql.AbstractRequest)
218    */
219   public void cloneParsing(AbstractRequest request)
220   {
221     if (!request.isParsed())
222       return;
223     AlterRequest alterRequest = (AlterRequest) request;
224     cloneTableNameAndColumns((AbstractWriteRequest) request);
225     table = alterRequest.getDatabaseTable();
226     column = alterRequest.getColumn();
227     isParsed = true;
228   }
229 
230   /**
231    * Returns the table value.
232    * 
233    * @return Returns the table.
234    */
235   public DatabaseTable getDatabaseTable()
236   {
237     return table;
238   }
239 
240   /**
241    * Returns the column value.
242    * 
243    * @return Returns the column.
244    */
245   public DatabaseColumn getColumn()
246   {
247     return column;
248   }
249 
250   /**
251    * Returns the isAdd value.
252    * 
253    * @return Returns the isAdd.
254    */
255   public boolean isAdd()
256   {
257     return isAdd;
258   }
259 }
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