/**
* Method to return if it is valid to select the specified mapping for the specified statement for
* this datastore adapter. Sometimes, dependent on the type of the column(s), and what other
* components are present in the statement, it may be invalid to select the mapping. This
* implementation returns true, so override in database-specific subclass as required.
*
* @param stmt The statement
* @param m The mapping that we want to select
* @return Whether it is valid
*/
public boolean validToSelectMappingInStatement(SelectStatement stmt, JavaTypeMapping m) {
if (m.getNumberOfDatastoreMappings() <= 0) {
return true;
}
for (int i = 0; i < m.getNumberOfDatastoreMappings(); i++) {
Column col = m.getDatastoreMapping(i).getColumn();
if (col.getJdbcType() == JdbcType.CLOB || col.getJdbcType() == JdbcType.BLOB) {
// "The ... data type cannot be selected as DISTINCT because it is not comparable."
if (stmt.isDistinct()) {
NucleusLogger.QUERY.debug(
"Not selecting " + m + " since is for BLOB/CLOB and using DISTINCT");
return false;
} else if (stmt.getNumberOfUnions() > 0) {
NucleusLogger.QUERY.debug(
"Not selecting " + m + " since is for BLOB/CLOB and using UNION");
return false;
}
}
}
return true;
}
/**
* Utility that does a discriminator candidate query for the specified candidate and subclasses
* and returns the class name of the instance that has the specified identity (if any).
*
* @param storeMgr RDBMS StoreManager
* @param ec execution context
* @param id The id
* @param cmd Metadata for the root candidate class
* @return Name of the class with this identity (or null if none found)
*/
public static String getClassNameForIdUsingDiscriminator(
RDBMSStoreManager storeMgr, ExecutionContext ec, Object id, AbstractClassMetaData cmd) {
// Check for input error
if (cmd == null || id == null) {
return null;
}
SQLExpressionFactory exprFactory = storeMgr.getSQLExpressionFactory();
ClassLoaderResolver clr = ec.getClassLoaderResolver();
DatastoreClass primaryTable = storeMgr.getDatastoreClass(cmd.getFullClassName(), clr);
// Form the query to find which one of these classes has the instance with this id
DiscriminatorStatementGenerator stmtGen =
new DiscriminatorStatementGenerator(
storeMgr, clr, clr.classForName(cmd.getFullClassName()), true, null, null);
stmtGen.setOption(SelectStatementGenerator.OPTION_RESTRICT_DISCRIM);
SelectStatement sqlStmt = stmtGen.getStatement();
// Select the discriminator
JavaTypeMapping discrimMapping = primaryTable.getDiscriminatorMapping(true);
SQLTable discrimSqlTbl =
SQLStatementHelper.getSQLTableForMappingOfTable(
sqlStmt, sqlStmt.getPrimaryTable(), discrimMapping);
sqlStmt.select(discrimSqlTbl, discrimMapping, null);
// Restrict to this id
JavaTypeMapping idMapping = primaryTable.getIdMapping();
JavaTypeMapping idParamMapping = new PersistableIdMapping((PersistableMapping) idMapping);
SQLExpression sqlFldExpr =
exprFactory.newExpression(sqlStmt, sqlStmt.getPrimaryTable(), idMapping);
SQLExpression sqlFldVal = exprFactory.newLiteralParameter(sqlStmt, idParamMapping, id, "ID");
sqlStmt.whereAnd(sqlFldExpr.eq(sqlFldVal), true);
// Perform the query
try {
ManagedConnection mconn = storeMgr.getConnection(ec);
SQLController sqlControl = storeMgr.getSQLController();
if (ec.getSerializeReadForClass(cmd.getFullClassName())) {
sqlStmt.addExtension(SQLStatement.EXTENSION_LOCK_FOR_UPDATE, true);
}
try {
PreparedStatement ps =
SQLStatementHelper.getPreparedStatementForSQLStatement(sqlStmt, ec, mconn, null, null);
String statement = sqlStmt.getSQLText().toSQL();
try {
ResultSet rs = sqlControl.executeStatementQuery(ec, mconn, statement, ps);
try {
if (rs != null) {
while (rs.next()) {
DiscriminatorMetaData dismd = discrimMapping.getTable().getDiscriminatorMetaData();
return RDBMSQueryUtils.getClassNameFromDiscriminatorResultSetRow(
discrimMapping, dismd, rs, ec);
}
}
} finally {
rs.close();
}
} finally {
sqlControl.closeStatement(mconn, ps);
}
} finally {
mconn.release();
}
} catch (SQLException sqe) {
NucleusLogger.DATASTORE.error("Exception thrown on querying of discriminator for id", sqe);
throw new NucleusDataStoreException(sqe.toString(), sqe);
}
return null;
}
/**
* Utility that does a union candidate query for the specified candidate(s) and subclasses and
* returns the class name of the instance that has the specified identity (if any).
*
* @param storeMgr RDBMS StoreManager
* @param ec execution context
* @param id The id
* @param rootCmds Metadata for the classes at the root
* @return Name of the class with this identity (or null if none found)
*/
public static String getClassNameForIdUsingUnion(
RDBMSStoreManager storeMgr,
ExecutionContext ec,
Object id,
List<AbstractClassMetaData> rootCmds) {
// Check for input error
if (rootCmds == null || rootCmds.isEmpty() || id == null) {
return null;
}
SQLExpressionFactory exprFactory = storeMgr.getSQLExpressionFactory();
ClassLoaderResolver clr = ec.getClassLoaderResolver();
// Form a query UNIONing all possible root candidates (and their subclasses)
Iterator<AbstractClassMetaData> rootCmdIter = rootCmds.iterator();
AbstractClassMetaData sampleCmd =
null; // Metadata for sample class in the tree so we can check if needs locking
SelectStatement sqlStmtMain = null;
while (rootCmdIter.hasNext()) {
AbstractClassMetaData rootCmd = rootCmdIter.next();
DatastoreClass rootTbl = storeMgr.getDatastoreClass(rootCmd.getFullClassName(), clr);
if (rootTbl == null) {
// Class must be using "subclass-table" (no table of its own) so find where it is
AbstractClassMetaData[] subcmds = storeMgr.getClassesManagingTableForClass(rootCmd, clr);
if (subcmds == null || subcmds.length == 0) {
// No table for this class so ignore
} else {
for (int i = 0; i < subcmds.length; i++) {
UnionStatementGenerator stmtGen =
new UnionStatementGenerator(
storeMgr,
clr,
clr.classForName(subcmds[i].getFullClassName()),
true,
null,
null);
stmtGen.setOption(SelectStatementGenerator.OPTION_SELECT_NUCLEUS_TYPE);
if (sqlStmtMain == null) {
sampleCmd = subcmds[i];
sqlStmtMain = stmtGen.getStatement();
// WHERE (object id) = ?
JavaTypeMapping idMapping = sqlStmtMain.getPrimaryTable().getTable().getIdMapping();
JavaTypeMapping idParamMapping =
new PersistableIdMapping((PersistableMapping) idMapping);
SQLExpression fieldExpr =
exprFactory.newExpression(sqlStmtMain, sqlStmtMain.getPrimaryTable(), idMapping);
SQLExpression fieldVal =
exprFactory.newLiteralParameter(sqlStmtMain, idParamMapping, id, "ID");
sqlStmtMain.whereAnd(fieldExpr.eq(fieldVal), true);
} else {
SelectStatement sqlStmt = stmtGen.getStatement();
// WHERE (object id) = ?
JavaTypeMapping idMapping = sqlStmt.getPrimaryTable().getTable().getIdMapping();
JavaTypeMapping idParamMapping =
new PersistableIdMapping((PersistableMapping) idMapping);
SQLExpression fieldExpr =
exprFactory.newExpression(sqlStmt, sqlStmt.getPrimaryTable(), idMapping);
SQLExpression fieldVal =
exprFactory.newLiteralParameter(sqlStmt, idParamMapping, id, "ID");
sqlStmt.whereAnd(fieldExpr.eq(fieldVal), true);
sqlStmtMain.union(sqlStmt);
}
}
}
} else {
UnionStatementGenerator stmtGen =
new UnionStatementGenerator(
storeMgr, clr, clr.classForName(rootCmd.getFullClassName()), true, null, null);
stmtGen.setOption(SelectStatementGenerator.OPTION_SELECT_NUCLEUS_TYPE);
if (sqlStmtMain == null) {
sampleCmd = rootCmd;
sqlStmtMain = stmtGen.getStatement();
// WHERE (object id) = ?
JavaTypeMapping idMapping = sqlStmtMain.getPrimaryTable().getTable().getIdMapping();
JavaTypeMapping idParamMapping = new PersistableIdMapping((PersistableMapping) idMapping);
SQLExpression fieldExpr =
exprFactory.newExpression(sqlStmtMain, sqlStmtMain.getPrimaryTable(), idMapping);
SQLExpression fieldVal =
exprFactory.newLiteralParameter(sqlStmtMain, idParamMapping, id, "ID");
sqlStmtMain.whereAnd(fieldExpr.eq(fieldVal), true);
} else {
SelectStatement sqlStmt = stmtGen.getStatement();
// WHERE (object id) = ?
JavaTypeMapping idMapping = sqlStmt.getPrimaryTable().getTable().getIdMapping();
JavaTypeMapping idParamMapping = new PersistableIdMapping((PersistableMapping) idMapping);
SQLExpression fieldExpr =
exprFactory.newExpression(sqlStmt, sqlStmt.getPrimaryTable(), idMapping);
SQLExpression fieldVal =
exprFactory.newLiteralParameter(sqlStmt, idParamMapping, id, "ID");
sqlStmt.whereAnd(fieldExpr.eq(fieldVal), true);
sqlStmtMain.union(sqlStmt);
}
}
}
// Perform the query
try {
ManagedConnection mconn = storeMgr.getConnection(ec);
SQLController sqlControl = storeMgr.getSQLController();
if (ec.getSerializeReadForClass(sampleCmd.getFullClassName())) {
sqlStmtMain.addExtension(SQLStatement.EXTENSION_LOCK_FOR_UPDATE, true);
}
try {
PreparedStatement ps =
SQLStatementHelper.getPreparedStatementForSQLStatement(
sqlStmtMain, ec, mconn, null, null);
String statement = sqlStmtMain.getSQLText().toSQL();
try {
ResultSet rs = sqlControl.executeStatementQuery(ec, mconn, statement, ps);
try {
if (rs != null) {
while (rs.next()) {
try {
return rs.getString(UnionStatementGenerator.NUC_TYPE_COLUMN).trim();
} catch (SQLException sqle) {
}
}
}
} finally {
rs.close();
}
} finally {
sqlControl.closeStatement(mconn, ps);
}
} finally {
mconn.release();
}
} catch (SQLException sqe) {
NucleusLogger.DATASTORE.error("Exception with UNION statement", sqe);
throw new NucleusDataStoreException(sqe.toString());
}
return null;
}