/**
* loop through entry types to get required, optional, general and utility fields for this type.
*/
private static void refreshFields() {
if (SQLUtil.allFields == null) {
SQLUtil.allFields = new ArrayList<>();
} else {
SQLUtil.allFields.clear();
}
SQLUtil.uniqueListInsert(SQLUtil.allFields, BibtexFields.getAllFieldNames());
SQLUtil.uniqueListInsert(SQLUtil.allFields, BibtexFields.getAllPrivateFieldNames());
}
/**
* Process a query and returns only the first result of a result set as a String. To be used when
* it is certain that only one String (single cell) will be returned from the DB
*
* @param conn The Connection object to which the DML should be sent
* @param query The query statements to be processed
* @return String with the result returned from the database
* @throws SQLException
*/
public static String processQueryWithSingleResult(Connection conn, String query)
throws SQLException {
try (Statement sm = SQLUtil.executeQueryWithResults(conn, query);
ResultSet rs = sm.getResultSet()) {
rs.next();
String result = rs.getString(1);
rs.getStatement().close();
return result;
}
}
/**
* Utility method for processing DML with proper output
*
* @param out The output (PrintStream or Connection) object to which the DML should be sent
* @param dml The DML statements to be processed
*/
public static void processQuery(Object out, String dml) throws SQLException {
if (out instanceof PrintStream) {
PrintStream fout = (PrintStream) out;
fout.println(dml);
}
if (out instanceof Connection) {
Connection conn = (Connection) out;
SQLUtil.executeQuery(conn, dml);
}
}
/** @return Create a common separated field names */
public static String getFieldStr() {
// create comma separated list of field names
String field;
List<String> fieldNames = new ArrayList<>();
for (int i = 0; i < SQLUtil.getAllFields().size(); i++) {
field = SQLUtil.allFields.get(i);
if (SQLUtil.reservedDBWords.contains(field)) {
field += "_";
}
fieldNames.add(field);
}
return String.join(", ", fieldNames);
}
/**
* Utility method for processing DML with proper output
*
* @param out The output (PrintStream or Connection) object to which the DML should be sent
* @param query The DML statements to be processed
* @return the result of the statement
*/
public static AutoCloseable processQueryWithResults(Object out, String query)
throws SQLException {
if (out instanceof PrintStream) { // TODO: how to handle the PrintStream
// case?
PrintStream fout = (PrintStream) out;
fout.println(query);
return fout;
}
if (out instanceof Connection) {
Connection conn = (Connection) out;
return SQLUtil.executeQueryWithResults(conn, query);
}
return null;
}
/** @return All existent fields for a bibtex entry */
public static ArrayList<String> getAllFields() {
if (SQLUtil.allFields == null) {
SQLUtil.refreshFields();
}
return SQLUtil.allFields;
}
/**
* return a ResultSet with the result of a "SELECT *" query for a given table
*
* @param conn Connection to the database
* @param tableName String containing the name of the table you want to get the results.
* @return a ResultSet with the query result returned from the DB
* @throws SQLException
*/
public static ResultSet queryAllFromTable(Connection conn, String tableName) throws SQLException {
String query = "SELECT * FROM " + tableName + ';';
try (Statement res = (Statement) SQLUtil.processQueryWithResults(conn, query)) {
return res.getResultSet();
}
}
