| Methods Summary |
|---|
| public static void | close(java.sql.Statement stmt, java.sql.Connection con)Close a statement and connection.
if (stmt != null) {
try {
stmt.close();
} catch (Exception ignored1) {
}
}
if (con != null) {
try {
// return the connection to the pool
putPooledConnection(con);
} catch (Exception ignored2) {
}
}
|
| public static void | closeAllConnections()Close any connections that are still open. The Servlet will
call this method from its destroy() method.
// empty the connection pool and close all connections
emptyPool();
|
| private static synchronized void | emptyPool()
while (!availableConnections.isEmpty()) {
Connection con = (Connection) availableConnections.pop();
try {
con.close();
} catch (SQLException ignored) {
}
}
|
| public static java.sql.Connection | getConnection(java.lang.String dbURL)
// get a connection from the pool
return getPooledConnection(dbURL);
|
| public static java.lang.String | getLongString(java.sql.ResultSet rs, int columnIndex)
try {
InputStream in = rs.getAsciiStream(columnIndex);
if (in == null) {
return "";
}
byte[] arr = new byte[BUF_SIZE];
StringBuffer buf = new StringBuffer();
int numRead = in.read(arr);
while (numRead != -1) {
buf.append(new String(arr, 0, numRead));
numRead = in.read(arr);
}
return buf.toString();
} catch (IOException ioe) {
ioe.printStackTrace();
throw new SQLException(ioe.getMessage());
}
|
| public static synchronized long | getNextID(java.lang.String tableName, java.sql.Connection con)Compute a new unique ID. It is assumed that the specified table
has a column named 'id' of type 'long'. It is assumed that
that all parts of the program will use this method to compute
new IDs.
Statement stmt = null;
try {
// if a max has already been retreived from this table,
// compute the next id without hitting the database
if (tableToMaxIDMap.containsKey(tableName)) {
Long curMax = (Long) tableToMaxIDMap.get(tableName);
Long newMax = new Long(curMax.longValue() + 1L);
tableToMaxIDMap.put(tableName, newMax);
return newMax.longValue();
}
stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(
"SELECT MAX(id) FROM " + tableName);
long max = 0;
if (rs.next()) {
max = rs.getLong(1);
}
max++;
tableToMaxIDMap.put(tableName, new Long(max));
return max;
} finally {
// just close the statement
close(stmt, null);
}
|
| private static synchronized java.sql.Connection | getPooledConnection(java.lang.String dbURL)
if (!availableConnections.isEmpty()) {
System.out.println("Reusing a connection");
return (Connection) availableConnections.pop();
} else {
System.out.println("Creating a connection");
return DriverManager.getConnection(dbURL);
}
|
| private static synchronized void | putPooledConnection(java.sql.Connection con)
availableConnections.push(con);
|
| public static void | setLongString(java.sql.PreparedStatement stmt, int columnIndex, java.lang.String data)Store a long text field in the database. For example, a message's
text will be quite long and cannot be stored using JDBC's
setString() method.
if (data.length() > 0) {
stmt.setAsciiStream(columnIndex,
new ByteArrayInputStream(data.getBytes()),
data.length());
} else {
// this 'else' condition was introduced as a bug fix. It was
// discovered that the 'setAsciiStream' code shown above
// caused MS Access to throw a "function sequence error"
// when the string was zero length. This code now works.
stmt.setString(columnIndex, "");
}
|
