VTIMetaDataTemplate


1   /*
2   
3      Derby - Class org.apache.derby.vti.VTIMetaDataTemplate
4   
5      Licensed to the Apache Software Foundation (ASF) under one or more
6      contributor license agreements.  See the NOTICE file distributed with
7      this work for additional information regarding copyright ownership.
8      The ASF licenses this file to You under the Apache License, Version 2.0
9      (the "License"); you may not use this file except in compliance with
10     the License.  You may obtain a copy of the License at
11  
12        http://www.apache.org/licenses/LICENSE-2.0
13  
14     Unless required by applicable law or agreed to in writing, software
15     distributed under the License is distributed on an "AS IS" BASIS,
16     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17     See the License for the specific language governing permissions and
18     limitations under the License.
19  
20   */
21  
22  package org.apache.derby.vti;
23  
24  import java.sql.SQLException  ;
25  import java.sql.ResultSetMetaData  ;
26  
27  /**
28      An abstract implementation of ResultSetMetaData (JDBC 1.2) that is useful
29      when writing a VTI (virtual table interface).
30      
31      This class implements
32      most of the methods of ResultSetMetaData, each one throwing a SQLException
33      with the name of the method. A concrete subclass can then just implement
34      the methods not implemented here and override any methods it needs
35      to implement for correct functionality.
36      <P>
37      The methods not implemented here are
38      <UL>
39      <LI>getColumnCount()
40      <LI>getColumnType()
41      </UL>
42      <BR>
43      For virtual tables the database engine only calls methods defined
44      in the JDBC 1.2 definition of java.sql.ResultSetMetaData.
45      <BR>
46      Classes that implement a JDBC 2.0 conformant java.sql.ResultSetMetaData can be used
47      as the meta data for virtual tables.
48      <BR>
49      Developers can use the VTIMetaDataTemplate20 instead of this class when
50      developing in a Java 2 environment.
51   */
52  
53  public abstract class VTIMetaDataTemplate implements ResultSetMetaData   {
54  
55      /**
56       * Is the column automatically numbered, and thus read-only?
57       *
58       * @param column the first column is 1, the second is 2, ...
59       * @return true if the column is automatically numbered
60       * @exception SQLException if a database-access error occurs.
61       */
62      public boolean isAutoIncrement(int column) throws SQLException   {
63          throw new SQLException  ("isAutoIncrement");
64      }
65  
66  
67      /**
68       * Does a column's case matter?
69       *
70       * @param column the first column is 1, the second is 2, ...
71       * @return true if the column is case-sensitive
72       * @exception SQLException if a database-access error occurs.
73       */
74      public boolean isCaseSensitive(int column) throws SQLException   {
75          throw new SQLException  ("isCaseSensitive");
76      }
77      
78  
79      /**
80       * Can the column be used in a WHERE clause?
81       *
82       * @param column the first column is 1, the second is 2, ...
83       * @return true if the column is searchable
84       * @exception SQLException if a database-access error occurs.
85       */
86      public boolean isSearchable(int column) throws SQLException  {
87          throw new SQLException  ("isSearchable");
88      }
89  
90  
91      /**
92       * Is the column a cash value?
93       *
94       * @param column the first column is 1, the second is 2, ...
95       * @return true if the column is a cash value
96       * @exception SQLException if a database-access error occurs.
97       */
98      public boolean isCurrency(int column) throws SQLException  {
99          throw new SQLException  ("isCurrency");
100     }
101 
102 
103     /**
104      * Can you put a NULL in this column?       
105      *
106      * @param column the first column is 1, the second is 2, ...
107      * @return columnNoNulls, columnNullable or columnNullableUnknown
108      * @exception SQLException if a database-access error occurs.
109      */
110     public int isNullable(int column) throws SQLException  {
111         throw new SQLException  ("isNullable");
112     }
113 
114 
115     /**
116      * Is the column a signed number?
117      *
118      * @param column the first column is 1, the second is 2, ...
119      * @return true if the column is a signed number
120      * @exception SQLException if a database-access error occurs.
121      */
122     public boolean isSigned(int column) throws SQLException   {
123         throw new SQLException  ("isSigned");
124     }
125 
126 
127     /**
128      * What's the column's normal maximum width in chars?
129      *
130      * @param column the first column is 1, the second is 2, ...
131      * @return the column's maximum width
132      * @exception SQLException if a database-access error occurs.
133      */
134     public  int getColumnDisplaySize(int column) throws SQLException   {
135         throw new SQLException  ("getColumnDisplaySize");
136     }
137 
138 
139     /**
140      * What's the suggested column title for use in printouts and
141      * displays?
142      *
143      * @param column the first column is 1, the second is 2, ...
144      * @return the column's title
145      * @exception SQLException if a database-access error occurs.
146      */
147     public String   getColumnLabel(int column) throws SQLException   {
148         throw new SQLException  ("getColumnLabel");
149     }
150     
151 
152     /**
153      * What's a column's name?
154      *
155      * @param column the first column is 1, the second is 2, ...
156      * @return column name
157      * @exception SQLException if a database-access error occurs.
158      */
159     public String   getColumnName(int column) throws SQLException   {
160         throw new SQLException  ("getColumnName");
161     }
162 
163 
164     /**
165      * What's a column's table's schema?
166      *
167      * @param column the first column is 1, the second is 2, ...
168      * @return schema name or "" if not applicable
169      * @exception SQLException if a database-access error occurs.
170      */
171     public  String   getSchemaName(int column) throws SQLException   {
172         throw new SQLException  ("getSchemaName");
173     }
174 
175 
176     /**
177      * How many decimal digits are in the column?
178      *
179      * @param column the first column is 1, the second is 2, ...
180      * @return the column's precision
181      * @exception SQLException if a database-access error occurs.
182      */
183     public int getPrecision(int column) throws SQLException   {
184         throw new SQLException  ("getPrecision");
185     }
186 
187 
188     /**
189      * What's a column's number of digits to the right of the decimal point?
190      *
191      * @param column the first column is 1, the second is 2, ...
192      * @return the column's scale
193      * @exception SQLException if a database-access error occurs.
194      */
195     public  int getScale(int column) throws SQLException   {
196         throw new SQLException  ("getScale");
197     }
198     
199 
200     /**
201      * What's a column's table name? 
202      *
203      * @param column the first column is 1, the second is 2, ...
204      * @return the column's table name or "" if not applicable
205      * @exception SQLException if a database-access error occurs.
206      */
207     public  String   getTableName(int column) throws SQLException   {
208         throw new SQLException  ("getTableName");
209     }
210 
211 
212     /**
213      * What's a column's table's catalog name?
214      *
215      * @param column the first column is 1, the second is 2, ...
216      * @return the column's table's catalog name or "" if not applicable.
217      * @exception SQLException if a database-access error occurs.
218      */
219     public String   getCatalogName(int column) throws SQLException   {
220         throw new SQLException  ("getCatalogName");
221     }
222 
223 
224     /**
225      * What's a column's data source specific type name?
226      *
227      * @param column the first column is 1, the second is 2, ...
228      * @return the column's type name
229      * @exception SQLException if a database-access error occurs.
230      */
231     public  String   getColumnTypeName(int column) throws SQLException   {
232         throw new SQLException  ("getColumnTypeName");
233     }
234 
235 
236     /**
237      * Is a column definitely not writable?
238      *
239      * @param column the first column is 1, the second is 2, ...
240      * @return true - vti's are read only
241      *         false - column is not read-only
242      * @exception SQLException if a database-access error occurs.
243      */
244     public  boolean isReadOnly(int column) throws SQLException   {
245         return true;
246     }
247 
248 
249     /**
250      * Is it possible for a write on the column to succeed?
251      *
252      * @param column the first column is 1, the second is 2, ...
253      * @return true if column is possibly writable
254      * @exception SQLException if a database-access error occurs.
255      */
256     public  boolean isWritable(int column) throws SQLException   {
257         return false;
258     }
259 
260     /**
261      * Will a write on the column definitely succeed?   
262      *
263      * @param column the first column is 1, the second is 2, ...
264      * @return true if column is definitely writable
265      * @exception SQLException if a database-access error occurs.
266      */
267     public boolean isDefinitelyWritable(int column) throws SQLException   {
268         return false;
269     }
270 
271     /*
272     ** JDBC 2.0
273     */
274 
275     /**
276      * Returns the fully-qualified name of the Java class whose instances
277      * are manufactured if the method <code>ResultSet.<!-- -->getObject</code>
278      * is called to retrieve a value from the column. JDBC 2.0.
279      *
280      * @exception SQLException if a database-access error occurs
281      */
282     public String   getColumnClassName(int column) throws SQLException   {
283         throw new SQLException  ("getColumnClassName");
284     }
285 }
286
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