some cleanups for the ClientInfo pull

- allocate clientInfo on demand
- move getMode() from JdbcDatabaseMetaData to JdbcConnection so we only
need to fetch it once per connection
- add minimal support for JdbcDatabaseMetaData#getClientInfoProperties

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,8 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Added support for Connection.setClientInfo() in compatibility modes for DB2, Postgresql, Oracle and MySQL.
+</li>
 <li>Issue #249: Clarify license declaration in Maven POM xml
 </li>
 <li>Fix NPE in querying spatial data through a sub-select.
@@ -52,9 +54,6 @@ table with an LOB column.
     when concurrently writing into MVStore.
 </li>
 <ul>
-<li>Added support for Connection.setClientInfo() in compatibility modes for DB2, Postgresql, Oracle and MySQL.
-</li>
-</ul>
 
 <h2>Version 1.4.191 Beta (2016-01-21)</h2>
 <ul>

h2/src/main/org/h2/jdbc/JdbcConnection.java

@@ -27,6 +27,16 @@ import java.sql.Savepoint;
 import java.sql.Statement;
 import java.sql.Struct;
 
+/*## Java 1.7 ##
+import java.util.concurrent.Executor;
+//*/
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+import java.util.regex.Pattern;
 import org.h2.api.ErrorCode;
 import org.h2.command.CommandInterface;
 import org.h2.engine.ConnectionInfo;
@@ -47,17 +57,6 @@ import org.h2.value.ValueInt;
 import org.h2.value.ValueNull;
 import org.h2.value.ValueString;
 
-/*## Java 1.7 ##
-import java.util.concurrent.Executor;
-//*/
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Properties;
-import java.util.regex.Pattern;
-
 /**
  * <p>
  * Represents a connection (session) to a database.
@@ -94,6 +93,7 @@ public class JdbcConnection extends TraceObject implements Connection {
     private int queryTimeoutCache = -1;
 
     private Map<String, String> clientInfo;
+    private String mode;
 
     /**
      * INTERNAL
@@ -128,7 +128,6 @@ public class JdbcConnection extends TraceObject implements Connection {
             this.url = ci.getURL();
             closeOld();
             watcher = CloseWatcher.register(this, session, keepOpenStackTrace);
-            this.clientInfo = new HashMap<String, String>();
         } catch (Exception e) {
             throw logAndConvert(e);
         }
@@ -152,8 +151,10 @@ public class JdbcConnection extends TraceObject implements Connection {
         this.getReadOnly = clone.getReadOnly;
         this.rollback = clone.rollback;
         this.watcher = null;
+        if (clone.clientInfo != null) {
             this.clientInfo = new HashMap<String, String>(clone.clientInfo);
         }
+    }
 
     /**
      * INTERNAL
@@ -1705,9 +1706,13 @@ public class JdbcConnection extends TraceObject implements Connection {
                 throw new SQLClientInfoException("Property name '" + name + " is used internally by H2.",
                     Collections.<String, ClientInfoStatus> emptyMap());
             }
-            Pattern clientInfoNameRegEx = getMode().supportedClientInfoPropertiesRegEx;
+
+            Pattern clientInfoNameRegEx = Mode.getInstance(getMode()).supportedClientInfoPropertiesRegEx;
 
             if (clientInfoNameRegEx != null && clientInfoNameRegEx.matcher(name).matches()) {
+                if (clientInfo == null) {
+                    clientInfo = new HashMap<String, String>();
+                }
                 clientInfo.put(name, value);
             } else {
                 throw new SQLClientInfoException("Client info name '" + name + "' not supported.",
@@ -1718,14 +1723,10 @@ public class JdbcConnection extends TraceObject implements Connection {
         }
     }
 
-    private boolean isInternalProperty(String name) {
+    private static boolean isInternalProperty(String name) {
         return NUM_SERVERS.equals(name) || name.startsWith(PREFIX_SERVER);
     }
 
-    private Mode getMode() throws SQLException {
-        return Mode.getInstance(((JdbcDatabaseMetaData) getMetaData()).getMode());
-    }
-
     private static SQLClientInfoException convertToClientInfoException(
             SQLException x) {
         if (x instanceof SQLClientInfoException) {
@@ -1750,7 +1751,11 @@ public class JdbcConnection extends TraceObject implements Connection {
                 debugCode("setClientInfo(properties);");
             }
             checkClosed();
+            if (clientInfo == null) {
+                clientInfo = new HashMap<String, String>();
+            } else {
                 clientInfo.clear();
+            }
             for (Map.Entry<Object, Object> entry : properties.entrySet()) {
                 setClientInfo((String) entry.getKey(), (String) entry.getValue());
             }
@@ -1774,9 +1779,11 @@ public class JdbcConnection extends TraceObject implements Connection {
             ArrayList<String> serverList = session.getClusterServers();
             Properties p = new Properties();
 
+            if (clientInfo != null) {
                 for (Map.Entry<String, String> entry : clientInfo.entrySet()) {
                     p.setProperty(entry.getKey(), entry.getValue());
                 }
+            }
 
             p.setProperty(NUM_SERVERS, String.valueOf(serverList.size()));
             for (int i = 0; i < serverList.size(); i++) {
@@ -1994,4 +2001,17 @@ public class JdbcConnection extends TraceObject implements Connection {
         trace.setLevel(level);
     }
 
+    String getMode() throws SQLException {
+        if (mode == null) {
+            PreparedStatement prep = prepareStatement(
+                    "SELECT VALUE FROM INFORMATION_SCHEMA.SETTINGS WHERE NAME=?");
+            prep.setString(1, "MODE");
+            ResultSet rs = prep.executeQuery();
+            rs.next();
+            mode = rs.getString(1);
+            prep.close();
+        }
+        return mode;
+    }
+
 }

h2/src/main/org/h2/jdbc/JdbcDatabaseMetaData.java

@@ -11,8 +11,8 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.RowIdLifetime;
 import java.sql.SQLException;
+import java.sql.Types;
 import java.util.Properties;
-
 import org.h2.engine.Constants;
 import org.h2.engine.SysProperties;
 import org.h2.message.DbException;
@@ -29,7 +29,6 @@ public class JdbcDatabaseMetaData extends TraceObject implements
         DatabaseMetaData {
 
     private final JdbcConnection conn;
-    private String mode;
 
     JdbcDatabaseMetaData(JdbcConnection conn, Trace trace, int id) {
         setTrace(trace, TraceObject.DATABASE_META_DATA, id);
@@ -2452,7 +2451,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean supportsMixedCaseQuotedIdentifiers() throws SQLException {
         debugCodeCall("supportsMixedCaseQuotedIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return false;
         }
@@ -2468,7 +2467,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean storesUpperCaseIdentifiers() throws SQLException {
         debugCodeCall("storesUpperCaseIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return false;
         }
@@ -2484,7 +2483,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean storesLowerCaseIdentifiers() throws SQLException {
         debugCodeCall("storesLowerCaseIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return true;
         }
@@ -2512,7 +2511,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean storesUpperCaseQuotedIdentifiers() throws SQLException {
         debugCodeCall("storesUpperCaseQuotedIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return true;
         }
@@ -2528,7 +2527,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean storesLowerCaseQuotedIdentifiers() throws SQLException {
         debugCodeCall("storesLowerCaseQuotedIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return true;
         }
@@ -2544,7 +2543,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public boolean storesMixedCaseQuotedIdentifiers() throws SQLException {
         debugCodeCall("storesMixedCaseQuotedIdentifiers");
-        String m = getMode();
+        String m = conn.getMode();
         if (m.equals("MySQL")) {
             return false;
         }
@@ -3074,14 +3073,16 @@ public class JdbcDatabaseMetaData extends TraceObject implements
         return false;
     }
 
-    /**
-     * [Not supported] Returns the client info properties.
-     */
     @Override
     public ResultSet getClientInfoProperties() throws SQLException {
         Properties clientInfo = conn.getClientInfo();
-        // we don't have any client properties, so return an empty result set
-        return new SimpleResultSet();
+        SimpleResultSet result = new SimpleResultSet();
+        result.addColumn("Name", Types.VARCHAR, 0, 0);
+        result.addColumn("Value", Types.VARCHAR, 0, 0);
+        for (Object key : clientInfo.keySet()) {
+            result.addRow(key, clientInfo.get(key));
+        }
+        return result;
     }
 
     /**
@@ -3166,17 +3167,4 @@ public class JdbcDatabaseMetaData extends TraceObject implements
         return getTraceObjectName() + ": " + conn;
     }
 
-    String getMode() throws SQLException {
-        if (mode == null) {
-            PreparedStatement prep = conn.prepareStatement(
-                    "SELECT VALUE FROM INFORMATION_SCHEMA.SETTINGS WHERE NAME=?");
-            prep.setString(1, "MODE");
-            ResultSet rs = prep.executeQuery();
-            rs.next();
-            mode = rs.getString(1);
-            prep.close();
-        }
-        return mode;
-    }
-
 }

h2/src/test/org/h2/test/jdbc/TestMetaData.java

@@ -13,7 +13,6 @@ import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.sql.Types;
-
 import org.h2.api.ErrorCode;
 import org.h2.engine.Constants;
 import org.h2.test.TestBase;
@@ -1201,6 +1200,7 @@ public class TestMetaData extends TestBase {
         assertNull(conn.getClientInfo("xxx"));
         DatabaseMetaData meta = conn.getMetaData();
         ResultSet rs = meta.getClientInfoProperties();
+        assertTrue(rs.next());
         assertFalse(rs.next());
         conn.close();
         deleteDb("metaData");