26 package com.sun.rowset.internal;
27
28 import java.sql.*;
29 import javax.sql.*;
30 import java.util.*;
31 import java.io.*;
32 import sun.reflect.misc.ReflectUtil;
33
34 import com.sun.rowset.*;
35 import java.text.MessageFormat;
36 import javax.sql.rowset.*;
37 import javax.sql.rowset.serial.SQLInputImpl;
38 import javax.sql.rowset.serial.SerialArray;
39 import javax.sql.rowset.serial.SerialBlob;
40 import javax.sql.rowset.serial.SerialClob;
41 import javax.sql.rowset.serial.SerialStruct;
42 import javax.sql.rowset.spi.*;
43
44
45 /**
46 * The facility called on internally by the <code>RIOptimisticProvider</code> implementation to
47 * propagate changes back to the data source from which the rowset got its data.
48 * <P>
49 * A <code>CachedRowSetWriter</code> object, called a writer, has the public
50 * method <code>writeData</code> for writing modified data to the underlying data source.
51 * This method is invoked by the rowset internally and is never invoked directly by an application.
52 * A writer also has public methods for setting and getting
53 * the <code>CachedRowSetReader</code> object, called a reader, that is associated
54 * with the writer. The remainder of the methods in this class are private and
55 * are invoked internally, either directly or indirectly, by the method
56 * <code>writeData</code>.
57 * <P>
58 * Typically the <code>SyncFactory</code> manages the <code>RowSetReader</code> and
59 * the <code>RowSetWriter</code> implementations using <code>SyncProvider</code> objects.
60 * Standard JDBC RowSet implementations provide an object instance of this
61 * writer by invoking the <code>SyncProvider.getRowSetWriter()</code> method.
62 *
63 * @version 0.2
64 * @author Jonathan Bruce
65 * @see javax.sql.rowset.spi.SyncProvider
66 * @see javax.sql.rowset.spi.SyncFactory
67 * @see javax.sql.rowset.spi.SyncFactoryException
68 */
69 public class CachedRowSetWriter implements TransactionalWriter, Serializable {
70
71 /**
72 * The <code>Connection</code> object that this writer will use to make a
73 * connection to the data source to which it will write data.
74 *
75 */
76 private transient Connection con;
77
78 /**
79 * The SQL <code>SELECT</code> command that this writer will call
80 * internally. The method <code>initSQLStatements</code> builds this
81 * command by supplying the words "SELECT" and "FROM," and using
82 * metadata to get the table name and column names .
83 *
84 * @serial
85 */
86 private String selectCmd;
87
88 /**
89 * The SQL <code>UPDATE</code> command that this writer will call
90 * internally to write data to the rowset's underlying data source.
91 * The method <code>initSQLStatements</code> builds this <code>String</code>
92 * object.
93 *
94 * @serial
95 */
96 private String updateCmd;
97
98 /**
99 * The SQL <code>WHERE</code> clause the writer will use for update
100 * statements in the <code>PreparedStatement</code> object
101 * it sends to the underlying data source.
102 *
103 * @serial
104 */
105 private String updateWhere;
106
107 /**
108 * The SQL <code>DELETE</code> command that this writer will call
109 * internally to delete a row in the rowset's underlying data source.
110 *
111 * @serial
112 */
113 private String deleteCmd;
114
115 /**
116 * The SQL <code>WHERE</code> clause the writer will use for delete
117 * statements in the <code>PreparedStatement</code> object
118 * it sends to the underlying data source.
119 *
120 * @serial
121 */
122 private String deleteWhere;
123
124 /**
125 * The SQL <code>INSERT INTO</code> command that this writer will internally use
126 * to insert data into the rowset's underlying data source. The method
127 * <code>initSQLStatements</code> builds this command with a question
128 * mark parameter placeholder for each column in the rowset.
129 *
130 * @serial
131 */
132 private String insertCmd;
133
134 /**
135 * An array containing the column numbers of the columns that are
136 * needed to uniquely identify a row in the <code>CachedRowSet</code> object
137 * for which this <code>CachedRowSetWriter</code> object is the writer.
138 *
139 * @serial
140 */
141 private int[] keyCols;
142
143 /**
144 * An array of the parameters that should be used to set the parameter
145 * placeholders in a <code>PreparedStatement</code> object that this
146 * writer will execute.
147 *
148 * @serial
149 */
150 private Object[] params;
151
152 /**
153 * The <code>CachedRowSetReader</code> object that has been
154 * set as the reader for the <code>CachedRowSet</code> object
155 * for which this <code>CachedRowSetWriter</code> object is the writer.
156 *
157 * @serial
158 */
159 private CachedRowSetReader reader;
160
161 /**
162 * The <code>ResultSetMetaData</code> object that contains information
163 * about the columns in the <code>CachedRowSet</code> object
164 * for which this <code>CachedRowSetWriter</code> object is the writer.
165 *
166 * @serial
167 */
168 private ResultSetMetaData callerMd;
169
170 /**
171 * The number of columns in the <code>CachedRowSet</code> object
172 * for which this <code>CachedRowSetWriter</code> object is the writer.
173 *
174 * @serial
175 */
176 private int callerColumnCount;
177
178 /**
179 * This <code>CachedRowSet<code> will hold the conflicting values
180 * retrieved from the db and hold it.
181 */
182 private CachedRowSetImpl crsResolve;
183
184 /**
185 * This {@code ArrayList} will hold the values of SyncResolver.*
186 */
187 private ArrayList<Integer> status;
188
189 /**
190 * This will check whether the same field value has changed both
191 * in database and CachedRowSet.
192 */
193 private int iChangedValsInDbAndCRS;
194
195 /**
196 * This will hold the number of cols for which the values have
197 * changed only in database.
198 */
199 private int iChangedValsinDbOnly ;
200
201 private JdbcRowSetResourceBundle resBundle;
202
203 public CachedRowSetWriter() {
204 try {
205 resBundle = JdbcRowSetResourceBundle.getJdbcRowSetResourceBundle();
206 } catch(IOException ioe) {
207 throw new RuntimeException(ioe);
208 }
209 }
210
211 /**
212 * Propagates changes in the given <code>RowSet</code> object
213 * back to its underlying data source and returns <code>true</code>
214 * if successful. The writer will check to see if
215 * the data in the pre-modified rowset (the original values) differ
216 * from the data in the underlying data source. If data in the data
217 * source has been modified by someone else, there is a conflict,
218 * and in that case, the writer will not write to the data source.
219 * In other words, the writer uses an optimistic concurrency algorithm:
220 * It checks for conflicts before making changes rather than restricting
221 * access for concurrent users.
222 * <P>
223 * This method is called by the rowset internally when
224 * the application invokes the method <code>acceptChanges</code>.
225 * The <code>writeData</code> method in turn calls private methods that
226 * it defines internally.
227 * The following is a general summary of what the method
228 * <code>writeData</code> does, much of which is accomplished
229 * through calls to its own internal methods.
230 * <OL>
231 * <LI>Creates a <code>CachedRowSet</code> object from the given
232 * <code>RowSet</code> object
233 * <LI>Makes a connection with the data source
234 * <UL>
235 * <LI>Disables autocommit mode if it is not already disabled
236 * <LI>Sets the transaction isolation level to that of the rowset
237 * </UL>
238 * <LI>Checks to see if the reader has read new data since the writer
239 * was last called and, if so, calls the method
240 * <code>initSQLStatements</code> to initialize new SQL statements
241 * <UL>
242 * <LI>Builds new <code>SELECT</code>, <code>UPDATE</code>,
243 * <code>INSERT</code>, and <code>DELETE</code> statements
244 * <LI>Uses the <code>CachedRowSet</code> object's metadata to
245 * determine the table name, column names, and the columns
246 * that make up the primary key
247 * </UL>
248 * <LI>When there is no conflict, propagates changes made to the
249 * <code>CachedRowSet</code> object back to its underlying data source
250 * <UL>
251 * <LI>Iterates through each row of the <code>CachedRowSet</code> object
252 * to determine whether it has been updated, inserted, or deleted
253 * <LI>If the corresponding row in the data source has not been changed
254 * since the rowset last read its
255 * values, the writer will use the appropriate command to update,
256 * insert, or delete the row
257 * <LI>If any data in the data source does not match the original values
258 * for the <code>CachedRowSet</code> object, the writer will roll
259 * back any changes it has made to the row in the data source.
260 * </UL>
261 * </OL>
262 *
263 * @return <code>true</code> if changes to the rowset were successfully
264 * written to the rowset's underlying data source;
265 * <code>false</code> otherwise
266 */
267 public boolean writeData(RowSetInternal caller) throws SQLException {
268 long conflicts = 0;
269 boolean showDel = false;
270 PreparedStatement pstmtIns = null;
271 iChangedValsInDbAndCRS = 0;
272 iChangedValsinDbOnly = 0;
273
274 // We assume caller is a CachedRowSet
275 CachedRowSetImpl crs = (CachedRowSetImpl)caller;
276 // crsResolve = new CachedRowSetImpl();
277 this.crsResolve = new CachedRowSetImpl();;
278
279 // The reader is registered with the writer at design time.
280 // This is not required, in general. The reader has logic
281 // to get a JDBC connection, so call it.
282
283 con = reader.connect(caller);
284
285
417
418 throw spe;
419 } else {
420 return true;
421 }
422 /*
423 if (conflict == true) {
424 con.rollback();
425 return false;
426 } else {
427 con.commit();
428 if (reader.getCloseConnection() == true) {
429 con.close();
430 }
431 return true;
432 }
433 */
434
435 } //end writeData
436
437 /**
438 * Updates the given <code>CachedRowSet</code> object's underlying data
439 * source so that updates to the rowset are reflected in the original
440 * data source, and returns <code>false</code> if the update was successful.
441 * A return value of <code>true</code> indicates that there is a conflict,
442 * meaning that a value updated in the rowset has already been changed by
443 * someone else in the underlying data source. A conflict can also exist
444 * if, for example, more than one row in the data source would be affected
445 * by the update or if no rows would be affected. In any case, if there is
446 * a conflict, this method does not update the underlying data source.
447 * <P>
448 * This method is called internally by the method <code>writeData</code>
449 * if a row in the <code>CachedRowSet</code> object for which this
450 * <code>CachedRowSetWriter</code> object is the writer has been updated.
451 *
452 * @return <code>false</code> if the update to the underlying data source is
453 * successful; <code>true</code> otherwise
454 * @throws SQLException if a database access error occurs
455 */
456 private boolean updateOriginalRow(CachedRowSet crs)
457 throws SQLException {
458 PreparedStatement pstmt;
459 int i = 0;
460 int idx = 0;
461
462 // Select the row from the database.
463 ResultSet origVals = crs.getOriginalRow();
464 origVals.next();
465
466 try {
467 updateWhere = buildWhereClause(updateWhere, origVals);
468
469
470 /**
471 * The following block of code is for checking a particular type of
472 * query where in there is a where clause. Without this block, if a
473 * SQL statement is built the "where" clause will appear twice hence
788 }
789 } catch (SQLException ex) {
790 ex.printStackTrace();
791 // if executeUpdate fails it will come here,
792 // update crsResolve with null rows
793 this.crsResolve.moveToInsertRow();
794
795 for(i = 1; i <= callerColumnCount; i++) {
796 this.crsResolve.updateNull(i);
797 }
798
799 this.crsResolve.insertRow();
800 this.crsResolve.moveToCurrentRow();
801
802 return true;
803 }
804 }
805
806 /**
807 * Inserts a row that has been inserted into the given
808 * <code>CachedRowSet</code> object into the data source from which
809 * the rowset is derived, returning <code>false</code> if the insertion
810 * was successful.
811 *
812 * @param crs the <code>CachedRowSet</code> object that has had a row inserted
813 * and to whose underlying data source the row will be inserted
814 * @param pstmt the <code>PreparedStatement</code> object that will be used
815 * to execute the insertion
816 * @return <code>false</code> to indicate that the insertion was successful;
817 * <code>true</code> otherwise
818 * @throws SQLException if a database access error occurs
819 */
820 private boolean insertNewRow(CachedRowSet crs,
821 PreparedStatement pstmt, CachedRowSetImpl crsRes) throws SQLException {
822
823 boolean returnVal = false;
824
825 try (PreparedStatement pstmtSel = con.prepareStatement(selectCmd,
826 ResultSet.TYPE_SCROLL_SENSITIVE,
827 ResultSet.CONCUR_READ_ONLY);
828 ResultSet rs = pstmtSel.executeQuery();
829 ResultSet rs2 = con.getMetaData().getPrimaryKeys(null, null,
830 crs.getTableName())
831 ) {
832
833 ResultSetMetaData rsmd = crs.getMetaData();
834 int icolCount = rsmd.getColumnCount();
835 String[] primaryKeys = new String[icolCount];
836 int k = 0;
837 while (rs2.next()) {
900 * Cursor will come here if executeUpdate fails.
901 * There can be many reasons why the insertion failed,
902 * one can be violation of primary key.
903 * Hence we cannot exactly identify why the insertion failed,
904 * present the current row as a null row to the caller.
905 */
906 this.crsResolve.moveToInsertRow();
907
908 for (int i = 1; i <= icolCount; i++) {
909 this.crsResolve.updateNull(i);
910 }
911
912 this.crsResolve.insertRow();
913 this.crsResolve.moveToCurrentRow();
914
915 return true;
916 }
917 }
918 }
919
920 /**
921 * Deletes the row in the underlying data source that corresponds to
922 * a row that has been deleted in the given <code> CachedRowSet</code> object
923 * and returns <code>false</code> if the deletion was successful.
924 * <P>
925 * This method is called internally by this writer's <code>writeData</code>
926 * method when a row in the rowset has been deleted. The values in the
927 * deleted row are the same as those that are stored in the original row
928 * of the given <code>CachedRowSet</code> object. If the values in the
929 * original row differ from the row in the underlying data source, the row
930 * in the data source is not deleted, and <code>deleteOriginalRow</code>
931 * returns <code>true</code> to indicate that there was a conflict.
932 *
933 *
934 * @return <code>false</code> if the deletion was successful, which means that
935 * there was no conflict; <code>true</code> otherwise
936 * @throws SQLException if there was a database access error
937 */
938 private boolean deleteOriginalRow(CachedRowSet crs, CachedRowSetImpl crsRes) throws SQLException {
939 PreparedStatement pstmt;
940 int i;
941 int idx = 0;
942 String strSelect;
943 // Select the row from the database.
944 ResultSet origVals = crs.getOriginalRow();
945 origVals.next();
946
947 deleteWhere = buildWhereClause(deleteWhere, origVals);
948 pstmt = con.prepareStatement(selectCmd + deleteWhere,
949 ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
950
951 for (i = 0; i < keyCols.length; i++) {
952 if (params[i] != null) {
953 pstmt.setObject(++idx, params[i]);
954 } else {
955 continue;
1039
1040 /**
1041 * Sets the reader for this writer to the given reader.
1042 *
1043 * @throws SQLException if a database access error occurs
1044 */
1045 public void setReader(CachedRowSetReader reader) throws SQLException {
1046 this.reader = reader;
1047 }
1048
1049 /**
1050 * Gets the reader for this writer.
1051 *
1052 * @throws SQLException if a database access error occurs
1053 */
1054 public CachedRowSetReader getReader() throws SQLException {
1055 return reader;
1056 }
1057
1058 /**
1059 * Composes a <code>SELECT</code>, <code>UPDATE</code>, <code>INSERT</code>,
1060 * and <code>DELETE</code> statement that can be used by this writer to
1061 * write data to the data source backing the given <code>CachedRowSet</code>
1062 * object.
1063 *
1064 * @ param caller a <code>CachedRowSet</code> object for which this
1065 * <code>CachedRowSetWriter</code> object is the writer
1066 * @throws SQLException if a database access error occurs
1067 */
1068 private void initSQLStatements(CachedRowSet caller) throws SQLException {
1069
1070 int i;
1071
1072 callerMd = caller.getMetaData();
1073 callerColumnCount = callerMd.getColumnCount();
1074 if (callerColumnCount < 1)
1075 // No data, so return.
1076 return;
1077
1078 /*
1079 * If the RowSet has a Table name we should use it.
1080 * This is really a hack to get round the fact that
1081 * a lot of the jdbc drivers can't provide the tab.
1082 */
1083 String table = caller.getTableName();
1084 if (table == null) {
1085 /*
1160 insertCmd += ")";
1161 }
1162
1163 /*
1164 * Compose a DELETE statement.
1165 */
1166 deleteCmd = "DELETE FROM " + buildTableName(dbmd, catalog, schema, table);
1167
1168 /*
1169 * set the key desriptors that will be
1170 * needed to construct where clauses.
1171 */
1172 buildKeyDesc(caller);
1173 }
1174
1175 /**
1176 * Returns a fully qualified table name built from the given catalog and
1177 * table names. The given metadata object is used to get the proper order
1178 * and separator.
1179 *
1180 * @param dbmd a <code>DatabaseMetaData</code> object that contains metadata
1181 * about this writer's <code>CachedRowSet</code> object
1182 * @param catalog a <code>String</code> object with the rowset's catalog
1183 * name
1184 * @param table a <code>String</code> object with the name of the table from
1185 * which this writer's rowset was derived
1186 * @return a <code>String</code> object with the fully qualified name of the
1187 * table from which this writer's rowset was derived
1188 * @throws SQLException if a database access error occurs
1189 */
1190 private String buildTableName(DatabaseMetaData dbmd,
1191 String catalog, String schema, String table) throws SQLException {
1192
1193 // trim all the leading and trailing whitespaces,
1194 // white spaces can never be catalog, schema or a table name.
1195
1196 String cmd = "";
1197
1198 catalog = catalog.trim();
1199 schema = schema.trim();
1200 table = table.trim();
1201
1202 if (dbmd.isCatalogAtStart() == true) {
1203 if (catalog != null && catalog.length() > 0) {
1204 cmd += catalog + dbmd.getCatalogSeparator();
1205 }
1206 if (schema != null && schema.length() > 0) {
1207 cmd += schema + ".";
1208 }
1209 cmd += table;
1210 } else {
1211 if (schema != null && schema.length() > 0) {
1212 cmd += schema + ".";
1213 }
1214 cmd += table;
1215 if (catalog != null && catalog.length() > 0) {
1216 cmd += dbmd.getCatalogSeparator() + catalog;
1217 }
1218 }
1219 cmd += " ";
1220 return cmd;
1221 }
1222
1223 /**
1224 * Assigns to the given <code>CachedRowSet</code> object's
1225 * <code>params</code>
1226 * field an array whose length equals the number of columns needed
1227 * to uniquely identify a row in the rowset. The array is given
1228 * values by the method <code>buildWhereClause</code>.
1229 * <P>
1230 * If the <code>CachedRowSet</code> object's <code>keyCols</code>
1231 * field has length <code>0</code> or is <code>null</code>, the array
1232 * is set with the column number of every column in the rowset.
1233 * Otherwise, the array in the field <code>keyCols</code> is set with only
1234 * the column numbers of the columns that are required to form a unique
1235 * identifier for a row.
1236 *
1237 * @param crs the <code>CachedRowSet</code> object for which this
1238 * <code>CachedRowSetWriter</code> object is the writer
1239 *
1240 * @throws SQLException if a database access error occurs
1241 */
1242 private void buildKeyDesc(CachedRowSet crs) throws SQLException {
1243
1244 keyCols = crs.getKeyColumns();
1245 ResultSetMetaData resultsetmd = crs.getMetaData();
1246 if (keyCols == null || keyCols.length == 0) {
1247 ArrayList<Integer> listKeys = new ArrayList<Integer>();
1248
1249 for (int i = 0; i < callerColumnCount; i++ ) {
1250 if(resultsetmd.getColumnType(i+1) != java.sql.Types.CLOB &&
1251 resultsetmd.getColumnType(i+1) != java.sql.Types.STRUCT &&
1252 resultsetmd.getColumnType(i+1) != java.sql.Types.SQLXML &&
1253 resultsetmd.getColumnType(i+1) != java.sql.Types.BLOB &&
1254 resultsetmd.getColumnType(i+1) != java.sql.Types.ARRAY &&
1255 resultsetmd.getColumnType(i+1) != java.sql.Types.OTHER )
1256 listKeys.add(i+1);
1257 }
1258 keyCols = new int[listKeys.size()];
1259 for (int i = 0; i < listKeys.size(); i++ )
1260 keyCols[i] = listKeys.get(i);
1261 }
1262 params = new Object[keyCols.length];
1263 }
1264
1265 /**
1266 * Constructs an SQL <code>WHERE</code> clause using the given
1267 * string as a starting point. The resulting clause will contain
1268 * a column name and " = ?" for each key column, that is, each column
1269 * that is needed to form a unique identifier for a row in the rowset.
1270 * This <code>WHERE</code> clause can be added to
1271 * a <code>PreparedStatement</code> object that updates, inserts, or
1272 * deletes a row.
1273 * <P>
1274 * This method uses the given result set to access values in the
1275 * <code>CachedRowSet</code> object that called this writer. These
1276 * values are used to build the array of parameters that will serve as
1277 * replacements for the "?" parameter placeholders in the
1278 * <code>PreparedStatement</code> object that is sent to the
1279 * <code>CachedRowSet</code> object's underlying data source.
1280 *
1281 * @param whereClause a <code>String</code> object that is an empty
1282 * string ("")
1283 * @param rs a <code>ResultSet</code> object that can be used
1284 * to access the <code>CachedRowSet</code> object's data
1285 * @return a <code>WHERE</code> clause of the form "<code>WHERE</code>
1286 * columnName = ? AND columnName = ? AND columnName = ? ..."
1287 * @throws SQLException if a database access error occurs
1288 */
1289 private String buildWhereClause(String whereClause,
1290 ResultSet rs) throws SQLException {
1291 whereClause = "WHERE ";
1292
1293 for (int i = 0; i < keyCols.length; i++) {
1294 if (i > 0) {
1295 whereClause += "AND ";
1296 }
1297 whereClause += callerMd.getColumnName(keyCols[i]);
1298 params[i] = rs.getObject(keyCols[i]);
1299 if (rs.wasNull() == true) {
1300 whereClause += " IS NULL ";
1301 } else {
1302 whereClause += " = ? ";
1303 }
1304 }
1305 return whereClause;
|
26 package com.sun.rowset.internal;
27
28 import java.sql.*;
29 import javax.sql.*;
30 import java.util.*;
31 import java.io.*;
32 import sun.reflect.misc.ReflectUtil;
33
34 import com.sun.rowset.*;
35 import java.text.MessageFormat;
36 import javax.sql.rowset.*;
37 import javax.sql.rowset.serial.SQLInputImpl;
38 import javax.sql.rowset.serial.SerialArray;
39 import javax.sql.rowset.serial.SerialBlob;
40 import javax.sql.rowset.serial.SerialClob;
41 import javax.sql.rowset.serial.SerialStruct;
42 import javax.sql.rowset.spi.*;
43
44
45 /**
46 * The facility called on internally by the {@code RIOptimisticProvider} implementation to
47 * propagate changes back to the data source from which the rowset got its data.
48 * <P>
49 * A {@code CachedRowSetWriter} object, called a writer, has the public
50 * method {@code writeData} for writing modified data to the underlying data source.
51 * This method is invoked by the rowset internally and is never invoked directly by an application.
52 * A writer also has public methods for setting and getting
53 * the {@code CachedRowSetReader} object, called a reader, that is associated
54 * with the writer. The remainder of the methods in this class are private and
55 * are invoked internally, either directly or indirectly, by the method
56 * {@code writeData}.
57 * <P>
58 * Typically the {@code SyncFactory} manages the {@code RowSetReader} and
59 * the {@code RowSetWriter} implementations using {@code SyncProvider} objects.
60 * Standard JDBC RowSet implementations provide an object instance of this
61 * writer by invoking the {@code SyncProvider.getRowSetWriter()} method.
62 *
63 * @version 0.2
64 * @author Jonathan Bruce
65 * @see javax.sql.rowset.spi.SyncProvider
66 * @see javax.sql.rowset.spi.SyncFactory
67 * @see javax.sql.rowset.spi.SyncFactoryException
68 */
69 public class CachedRowSetWriter implements TransactionalWriter, Serializable {
70
71 /**
72 * The {@code Connection} object that this writer will use to make a
73 * connection to the data source to which it will write data.
74 *
75 */
76 private transient Connection con;
77
78 /**
79 * The SQL {@code SELECT} command that this writer will call
80 * internally. The method {@code initSQLStatements} builds this
81 * command by supplying the words "SELECT" and "FROM," and using
82 * metadata to get the table name and column names .
83 *
84 * @serial
85 */
86 private String selectCmd;
87
88 /**
89 * The SQL {@code UPDATE} command that this writer will call
90 * internally to write data to the rowset's underlying data source.
91 * The method {@code initSQLStatements} builds this {@code String}
92 * object.
93 *
94 * @serial
95 */
96 private String updateCmd;
97
98 /**
99 * The SQL {@code WHERE} clause the writer will use for update
100 * statements in the {@code PreparedStatement} object
101 * it sends to the underlying data source.
102 *
103 * @serial
104 */
105 private String updateWhere;
106
107 /**
108 * The SQL {@code DELETE} command that this writer will call
109 * internally to delete a row in the rowset's underlying data source.
110 *
111 * @serial
112 */
113 private String deleteCmd;
114
115 /**
116 * The SQL {@code WHERE} clause the writer will use for delete
117 * statements in the {@code PreparedStatement} object
118 * it sends to the underlying data source.
119 *
120 * @serial
121 */
122 private String deleteWhere;
123
124 /**
125 * The SQL {@code INSERT INTO} command that this writer will internally use
126 * to insert data into the rowset's underlying data source. The method
127 * {@code initSQLStatements} builds this command with a question
128 * mark parameter placeholder for each column in the rowset.
129 *
130 * @serial
131 */
132 private String insertCmd;
133
134 /**
135 * An array containing the column numbers of the columns that are
136 * needed to uniquely identify a row in the {@code CachedRowSet} object
137 * for which this {@code CachedRowSetWriter} object is the writer.
138 *
139 * @serial
140 */
141 private int[] keyCols;
142
143 /**
144 * An array of the parameters that should be used to set the parameter
145 * placeholders in a {@code PreparedStatement} object that this
146 * writer will execute.
147 *
148 * @serial
149 */
150 private Object[] params;
151
152 /**
153 * The {@code CachedRowSetReader} object that has been
154 * set as the reader for the {@code CachedRowSet} object
155 * for which this {@code CachedRowSetWriter} object is the writer.
156 *
157 * @serial
158 */
159 private CachedRowSetReader reader;
160
161 /**
162 * The {@code ResultSetMetaData} object that contains information
163 * about the columns in the {@code CachedRowSet} object
164 * for which this {@code CachedRowSetWriter} object is the writer.
165 *
166 * @serial
167 */
168 private ResultSetMetaData callerMd;
169
170 /**
171 * The number of columns in the {@code CachedRowSet} object
172 * for which this {@code CachedRowSetWriter} object is the writer.
173 *
174 * @serial
175 */
176 private int callerColumnCount;
177
178 /**
179 * This {@code CachedRowSet} will hold the conflicting values
180 * retrieved from the db and hold it.
181 */
182 private CachedRowSetImpl crsResolve;
183
184 /**
185 * This {@code ArrayList} will hold the values of SyncResolver.*
186 */
187 private ArrayList<Integer> status;
188
189 /**
190 * This will check whether the same field value has changed both
191 * in database and CachedRowSet.
192 */
193 private int iChangedValsInDbAndCRS;
194
195 /**
196 * This will hold the number of cols for which the values have
197 * changed only in database.
198 */
199 private int iChangedValsinDbOnly ;
200
201 private JdbcRowSetResourceBundle resBundle;
202
203 public CachedRowSetWriter() {
204 try {
205 resBundle = JdbcRowSetResourceBundle.getJdbcRowSetResourceBundle();
206 } catch(IOException ioe) {
207 throw new RuntimeException(ioe);
208 }
209 }
210
211 /**
212 * Propagates changes in the given {@code RowSet} object
213 * back to its underlying data source and returns {@code true}
214 * if successful. The writer will check to see if
215 * the data in the pre-modified rowset (the original values) differ
216 * from the data in the underlying data source. If data in the data
217 * source has been modified by someone else, there is a conflict,
218 * and in that case, the writer will not write to the data source.
219 * In other words, the writer uses an optimistic concurrency algorithm:
220 * It checks for conflicts before making changes rather than restricting
221 * access for concurrent users.
222 * <P>
223 * This method is called by the rowset internally when
224 * the application invokes the method {@code acceptChanges}.
225 * The {@code writeData} method in turn calls private methods that
226 * it defines internally.
227 * The following is a general summary of what the method
228 * {@code writeData} does, much of which is accomplished
229 * through calls to its own internal methods.
230 * <OL>
231 * <LI>Creates a {@code CachedRowSet} object from the given
232 * {@code RowSet} object
233 * <LI>Makes a connection with the data source
234 * <UL>
235 * <LI>Disables autocommit mode if it is not already disabled
236 * <LI>Sets the transaction isolation level to that of the rowset
237 * </UL>
238 * <LI>Checks to see if the reader has read new data since the writer
239 * was last called and, if so, calls the method
240 * {@code initSQLStatements} to initialize new SQL statements
241 * <UL>
242 * <LI>Builds new {@code SELECT}, {@code UPDATE},
243 * {@code INSERT}, and {@code DELETE} statements
244 * <LI>Uses the {@code CachedRowSet} object's metadata to
245 * determine the table name, column names, and the columns
246 * that make up the primary key
247 * </UL>
248 * <LI>When there is no conflict, propagates changes made to the
249 * {@code CachedRowSet} object back to its underlying data source
250 * <UL>
251 * <LI>Iterates through each row of the {@code CachedRowSet} object
252 * to determine whether it has been updated, inserted, or deleted
253 * <LI>If the corresponding row in the data source has not been changed
254 * since the rowset last read its
255 * values, the writer will use the appropriate command to update,
256 * insert, or delete the row
257 * <LI>If any data in the data source does not match the original values
258 * for the {@code CachedRowSet} object, the writer will roll
259 * back any changes it has made to the row in the data source.
260 * </UL>
261 * </OL>
262 *
263 * @return {@code true} if changes to the rowset were successfully
264 * written to the rowset's underlying data source;
265 * {@code false} otherwise
266 */
267 public boolean writeData(RowSetInternal caller) throws SQLException {
268 long conflicts = 0;
269 boolean showDel = false;
270 PreparedStatement pstmtIns = null;
271 iChangedValsInDbAndCRS = 0;
272 iChangedValsinDbOnly = 0;
273
274 // We assume caller is a CachedRowSet
275 CachedRowSetImpl crs = (CachedRowSetImpl)caller;
276 // crsResolve = new CachedRowSetImpl();
277 this.crsResolve = new CachedRowSetImpl();;
278
279 // The reader is registered with the writer at design time.
280 // This is not required, in general. The reader has logic
281 // to get a JDBC connection, so call it.
282
283 con = reader.connect(caller);
284
285
417
418 throw spe;
419 } else {
420 return true;
421 }
422 /*
423 if (conflict == true) {
424 con.rollback();
425 return false;
426 } else {
427 con.commit();
428 if (reader.getCloseConnection() == true) {
429 con.close();
430 }
431 return true;
432 }
433 */
434
435 } //end writeData
436
437 /**
438 * Updates the given {@code CachedRowSet} object's underlying data
439 * source so that updates to the rowset are reflected in the original
440 * data source, and returns {@code false} if the update was successful.
441 * A return value of {@code true} indicates that there is a conflict,
442 * meaning that a value updated in the rowset has already been changed by
443 * someone else in the underlying data source. A conflict can also exist
444 * if, for example, more than one row in the data source would be affected
445 * by the update or if no rows would be affected. In any case, if there is
446 * a conflict, this method does not update the underlying data source.
447 * <P>
448 * This method is called internally by the method {@code writeData}
449 * if a row in the {@code CachedRowSet} object for which this
450 * {@code CachedRowSetWriter} object is the writer has been updated.
451 *
452 * @return {@code false} if the update to the underlying data source is
453 * successful; {@code true} otherwise
454 * @throws SQLException if a database access error occurs
455 */
456 private boolean updateOriginalRow(CachedRowSet crs)
457 throws SQLException {
458 PreparedStatement pstmt;
459 int i = 0;
460 int idx = 0;
461
462 // Select the row from the database.
463 ResultSet origVals = crs.getOriginalRow();
464 origVals.next();
465
466 try {
467 updateWhere = buildWhereClause(updateWhere, origVals);
468
469
470 /**
471 * The following block of code is for checking a particular type of
472 * query where in there is a where clause. Without this block, if a
473 * SQL statement is built the "where" clause will appear twice hence
788 }
789 } catch (SQLException ex) {
790 ex.printStackTrace();
791 // if executeUpdate fails it will come here,
792 // update crsResolve with null rows
793 this.crsResolve.moveToInsertRow();
794
795 for(i = 1; i <= callerColumnCount; i++) {
796 this.crsResolve.updateNull(i);
797 }
798
799 this.crsResolve.insertRow();
800 this.crsResolve.moveToCurrentRow();
801
802 return true;
803 }
804 }
805
806 /**
807 * Inserts a row that has been inserted into the given
808 * {@code CachedRowSet} object into the data source from which
809 * the rowset is derived, returning {@code false} if the insertion
810 * was successful.
811 *
812 * @param crs the {@code CachedRowSet} object that has had a row inserted
813 * and to whose underlying data source the row will be inserted
814 * @param pstmt the {@code PreparedStatement} object that will be used
815 * to execute the insertion
816 * @return {@code false} to indicate that the insertion was successful;
817 * {@code true} otherwise
818 * @throws SQLException if a database access error occurs
819 */
820 private boolean insertNewRow(CachedRowSet crs,
821 PreparedStatement pstmt, CachedRowSetImpl crsRes) throws SQLException {
822
823 boolean returnVal = false;
824
825 try (PreparedStatement pstmtSel = con.prepareStatement(selectCmd,
826 ResultSet.TYPE_SCROLL_SENSITIVE,
827 ResultSet.CONCUR_READ_ONLY);
828 ResultSet rs = pstmtSel.executeQuery();
829 ResultSet rs2 = con.getMetaData().getPrimaryKeys(null, null,
830 crs.getTableName())
831 ) {
832
833 ResultSetMetaData rsmd = crs.getMetaData();
834 int icolCount = rsmd.getColumnCount();
835 String[] primaryKeys = new String[icolCount];
836 int k = 0;
837 while (rs2.next()) {
900 * Cursor will come here if executeUpdate fails.
901 * There can be many reasons why the insertion failed,
902 * one can be violation of primary key.
903 * Hence we cannot exactly identify why the insertion failed,
904 * present the current row as a null row to the caller.
905 */
906 this.crsResolve.moveToInsertRow();
907
908 for (int i = 1; i <= icolCount; i++) {
909 this.crsResolve.updateNull(i);
910 }
911
912 this.crsResolve.insertRow();
913 this.crsResolve.moveToCurrentRow();
914
915 return true;
916 }
917 }
918 }
919
920 /**
921 * Deletes the row in the underlying data source that corresponds to
922 * a row that has been deleted in the given {@code CachedRowSet} object
923 * and returns {@code false} if the deletion was successful.
924 * <P>
925 * This method is called internally by this writer's {@code writeData}
926 * method when a row in the rowset has been deleted. The values in the
927 * deleted row are the same as those that are stored in the original row
928 * of the given {@code CachedRowSet} object. If the values in the
929 * original row differ from the row in the underlying data source, the row
930 * in the data source is not deleted, and {@code deleteOriginalRow}
931 * returns {@code true} to indicate that there was a conflict.
932 *
933 *
934 * @return {@code false} if the deletion was successful, which means that
935 * there was no conflict; {@code true} otherwise
936 * @throws SQLException if there was a database access error
937 */
938 private boolean deleteOriginalRow(CachedRowSet crs, CachedRowSetImpl crsRes) throws SQLException {
939 PreparedStatement pstmt;
940 int i;
941 int idx = 0;
942 String strSelect;
943 // Select the row from the database.
944 ResultSet origVals = crs.getOriginalRow();
945 origVals.next();
946
947 deleteWhere = buildWhereClause(deleteWhere, origVals);
948 pstmt = con.prepareStatement(selectCmd + deleteWhere,
949 ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
950
951 for (i = 0; i < keyCols.length; i++) {
952 if (params[i] != null) {
953 pstmt.setObject(++idx, params[i]);
954 } else {
955 continue;
1039
1040 /**
1041 * Sets the reader for this writer to the given reader.
1042 *
1043 * @throws SQLException if a database access error occurs
1044 */
1045 public void setReader(CachedRowSetReader reader) throws SQLException {
1046 this.reader = reader;
1047 }
1048
1049 /**
1050 * Gets the reader for this writer.
1051 *
1052 * @throws SQLException if a database access error occurs
1053 */
1054 public CachedRowSetReader getReader() throws SQLException {
1055 return reader;
1056 }
1057
1058 /**
1059 * Composes a {@code SELECT}, {@code UPDATE}, {@code INSERT},
1060 * and {@code DELETE} statement that can be used by this writer to
1061 * write data to the data source backing the given {@code CachedRowSet}
1062 * object.
1063 *
1064 * @param caller a {@code CachedRowSet} object for which this
1065 * {@code CachedRowSetWriter} object is the writer
1066 * @throws SQLException if a database access error occurs
1067 */
1068 private void initSQLStatements(CachedRowSet caller) throws SQLException {
1069
1070 int i;
1071
1072 callerMd = caller.getMetaData();
1073 callerColumnCount = callerMd.getColumnCount();
1074 if (callerColumnCount < 1)
1075 // No data, so return.
1076 return;
1077
1078 /*
1079 * If the RowSet has a Table name we should use it.
1080 * This is really a hack to get round the fact that
1081 * a lot of the jdbc drivers can't provide the tab.
1082 */
1083 String table = caller.getTableName();
1084 if (table == null) {
1085 /*
1160 insertCmd += ")";
1161 }
1162
1163 /*
1164 * Compose a DELETE statement.
1165 */
1166 deleteCmd = "DELETE FROM " + buildTableName(dbmd, catalog, schema, table);
1167
1168 /*
1169 * set the key desriptors that will be
1170 * needed to construct where clauses.
1171 */
1172 buildKeyDesc(caller);
1173 }
1174
1175 /**
1176 * Returns a fully qualified table name built from the given catalog and
1177 * table names. The given metadata object is used to get the proper order
1178 * and separator.
1179 *
1180 * @param dbmd a {@code DatabaseMetaData} object that contains metadata
1181 * about this writer's {@code CachedRowSet} object
1182 * @param catalog a {@code String} object with the rowset's catalog
1183 * name
1184 * @param table a {@code String} object with the name of the table from
1185 * which this writer's rowset was derived
1186 * @return a {@code String} object with the fully qualified name of the
1187 * table from which this writer's rowset was derived
1188 * @throws SQLException if a database access error occurs
1189 */
1190 private String buildTableName(DatabaseMetaData dbmd,
1191 String catalog, String schema, String table) throws SQLException {
1192
1193 // trim all the leading and trailing whitespaces,
1194 // white spaces can never be catalog, schema or a table name.
1195
1196 String cmd = "";
1197
1198 catalog = catalog.trim();
1199 schema = schema.trim();
1200 table = table.trim();
1201
1202 if (dbmd.isCatalogAtStart() == true) {
1203 if (catalog != null && catalog.length() > 0) {
1204 cmd += catalog + dbmd.getCatalogSeparator();
1205 }
1206 if (schema != null && schema.length() > 0) {
1207 cmd += schema + ".";
1208 }
1209 cmd += table;
1210 } else {
1211 if (schema != null && schema.length() > 0) {
1212 cmd += schema + ".";
1213 }
1214 cmd += table;
1215 if (catalog != null && catalog.length() > 0) {
1216 cmd += dbmd.getCatalogSeparator() + catalog;
1217 }
1218 }
1219 cmd += " ";
1220 return cmd;
1221 }
1222
1223 /**
1224 * Assigns to the given {@code CachedRowSet} object's
1225 * {@code params}
1226 * field an array whose length equals the number of columns needed
1227 * to uniquely identify a row in the rowset. The array is given
1228 * values by the method {@code buildWhereClause}.
1229 * <P>
1230 * If the {@code CachedRowSet} object's {@code keyCols}
1231 * field has length {@code 0} or is {@code null}, the array
1232 * is set with the column number of every column in the rowset.
1233 * Otherwise, the array in the field {@code keyCols} is set with only
1234 * the column numbers of the columns that are required to form a unique
1235 * identifier for a row.
1236 *
1237 * @param crs the {@code CachedRowSet} object for which this
1238 * {@code CachedRowSetWriter} object is the writer
1239 *
1240 * @throws SQLException if a database access error occurs
1241 */
1242 private void buildKeyDesc(CachedRowSet crs) throws SQLException {
1243
1244 keyCols = crs.getKeyColumns();
1245 ResultSetMetaData resultsetmd = crs.getMetaData();
1246 if (keyCols == null || keyCols.length == 0) {
1247 ArrayList<Integer> listKeys = new ArrayList<Integer>();
1248
1249 for (int i = 0; i < callerColumnCount; i++ ) {
1250 if(resultsetmd.getColumnType(i+1) != java.sql.Types.CLOB &&
1251 resultsetmd.getColumnType(i+1) != java.sql.Types.STRUCT &&
1252 resultsetmd.getColumnType(i+1) != java.sql.Types.SQLXML &&
1253 resultsetmd.getColumnType(i+1) != java.sql.Types.BLOB &&
1254 resultsetmd.getColumnType(i+1) != java.sql.Types.ARRAY &&
1255 resultsetmd.getColumnType(i+1) != java.sql.Types.OTHER )
1256 listKeys.add(i+1);
1257 }
1258 keyCols = new int[listKeys.size()];
1259 for (int i = 0; i < listKeys.size(); i++ )
1260 keyCols[i] = listKeys.get(i);
1261 }
1262 params = new Object[keyCols.length];
1263 }
1264
1265 /**
1266 * Constructs an SQL {@code WHERE} clause using the given
1267 * string as a starting point. The resulting clause will contain
1268 * a column name and " = ?" for each key column, that is, each column
1269 * that is needed to form a unique identifier for a row in the rowset.
1270 * This {@code WHERE} clause can be added to
1271 * a {@code PreparedStatement} object that updates, inserts, or
1272 * deletes a row.
1273 * <P>
1274 * This method uses the given result set to access values in the
1275 * {@code CachedRowSet} object that called this writer. These
1276 * values are used to build the array of parameters that will serve as
1277 * replacements for the "?" parameter placeholders in the
1278 * {@code PreparedStatement} object that is sent to the
1279 * {@code CachedRowSet} object's underlying data source.
1280 *
1281 * @param whereClause a {@code String} object that is an empty
1282 * string ("")
1283 * @param rs a {@code ResultSet} object that can be used
1284 * to access the {@code CachedRowSet} object's data
1285 * @return a {@code WHERE} clause of the form "{@code WHERE}
1286 * columnName = ? AND columnName = ? AND columnName = ? ..."
1287 * @throws SQLException if a database access error occurs
1288 */
1289 private String buildWhereClause(String whereClause,
1290 ResultSet rs) throws SQLException {
1291 whereClause = "WHERE ";
1292
1293 for (int i = 0; i < keyCols.length; i++) {
1294 if (i > 0) {
1295 whereClause += "AND ";
1296 }
1297 whereClause += callerMd.getColumnName(keyCols[i]);
1298 params[i] = rs.getObject(keyCols[i]);
1299 if (rs.wasNull() == true) {
1300 whereClause += " IS NULL ";
1301 } else {
1302 whereClause += " = ? ";
1303 }
1304 }
1305 return whereClause;
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