Changeset: b3ca1157be73 for monetdb-java
URL: https://dev.monetdb.org/hg/monetdb-java/rev/b3ca1157be73
Modified Files:
src/main/java/nl/cwi/monetdb/jdbc/MonetDatabaseMetaData.java
Branch: default
Log Message:
Improve DatabaseMetaData.getDatabaseProductVersion() to never return a null
String.
This prevents runtime NullPointerException in getTables() and getTableTypes().
Also improved error reporting when JDBC driver failed to fetch the value of
environment variable monet_version
as reported in bug 4038.
It will now throw an SQLException with the error message.
diffs (81 lines):
diff --git a/src/main/java/nl/cwi/monetdb/jdbc/MonetDatabaseMetaData.java
b/src/main/java/nl/cwi/monetdb/jdbc/MonetDatabaseMetaData.java
--- a/src/main/java/nl/cwi/monetdb/jdbc/MonetDatabaseMetaData.java
+++ b/src/main/java/nl/cwi/monetdb/jdbc/MonetDatabaseMetaData.java
@@ -27,6 +27,8 @@ import java.util.ArrayList;
*/
public class MonetDatabaseMetaData extends MonetWrapper implements
DatabaseMetaData {
private Connection con;
+
+ // Internal cache for 3 server environment values
private String env_current_user;
private String env_monet_version;
private String env_max_clients;
@@ -36,12 +38,11 @@ public class MonetDatabaseMetaData exten
}
/**
- * Internal cache for 3 environment values retrieved from the
- * server, to avoid querying the server over and over again.
- * Once a value is read, it is kept in the private env_* variables for
reuse.
- * We currently only need the env values of: current_user,
monet_version and max_clients.
+ * Utility method to fetch some server environment values combined in
one query for efficiency.
+ * We currently fetch the env values of: current_user, monet_version
and max_clients.
+ * We cache them locally such that we do not need to query the server
again and again.
*/
- private synchronized void getEnvValues() {
+ private synchronized void getEnvValues() throws SQLException {
Statement st = null;
ResultSet rs = null;
try {
@@ -65,8 +66,7 @@ public class MonetDatabaseMetaData exten
}
}
}
- } catch (SQLException e) {
- // ignore
+ /* do not catch SQLException here, as we want to know it when
it fails */
} finally {
if (rs != null) {
try {
@@ -224,7 +224,8 @@ public class MonetDatabaseMetaData exten
public String getDatabaseProductVersion() throws SQLException {
if (env_monet_version == null)
getEnvValues();
- return env_monet_version;
+ // always return a valid String to prevent NPE in getTables()
and getTableTypes()
+ return (env_monet_version != null) ? env_monet_version : "";
}
/**
@@ -1408,7 +1409,7 @@ public class MonetDatabaseMetaData exten
* @return the maximum number of connections
*/
@Override
- public int getMaxConnections() {
+ public int getMaxConnections() throws SQLException {
if (env_max_clients == null)
getEnvValues();
@@ -3611,7 +3612,7 @@ public class MonetDatabaseMetaData exten
if (env_monet_version != null) {
try {
int start = env_monet_version.indexOf(".");
- major =
Integer.parseInt(env_monet_version.substring(0, start));
+ major = Integer.parseInt((start >= 0) ?
env_monet_version.substring(0, start) : env_monet_version);
} catch (NumberFormatException e) {
// ignore
}
@@ -3633,8 +3634,11 @@ public class MonetDatabaseMetaData exten
if (env_monet_version != null) {
try {
int start = env_monet_version.indexOf(".");
- int end = env_monet_version.indexOf(".", start
+ 1);
- minor =
Integer.parseInt(env_monet_version.substring(start + 1, end));
+ if (start >= 0) {
+ start++;
+ int end =
env_monet_version.indexOf(".", start);
+ minor = Integer.parseInt((end > 0) ?
env_monet_version.substring(start, end) : env_monet_version.substring(start));
+ }
} catch (NumberFormatException e) {
// ignore
}
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