adjust limit expression for oracle 12.0 and below

as oracle 12.0 and below do not know the keywords limits and offset the
expression has to be adjusted to work with those versions of the oracle
database

src/plugins/monitoring/src/java/com/reucon/openfire/plugin/archive/impl/JdbcPersistenceManager.java

@@ -4,6 +4,7 @@ import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Date;
@@ -442,6 +443,36 @@ public class JdbcPersistenceManager implements PersistenceManager {
 				limitSB.append(" BETWEEN ").append(firstIndex+1);
 				limitSB.append(" AND ").append(firstIndex+max);
 			}
+			else if( isOracleDB() ) {
+				try {
+					final Statement statement = DbConnectionManager.getConnection().createStatement();
+					final ResultSet resultSet = statement.executeQuery( "select VERSION from PRODUCT_COMPONENT_VERSION P where P.PRODUCT like 'Oracle Database%'" );
+					resultSet.next();
+					final String versionString = resultSet.getString( "VERSION" );
+					final String[] versionParts = versionString.split( "\\." );
+					final int majorVersion = Integer.parseInt( versionParts[ 0 ] );
+					final int minorVersion = Integer.parseInt( versionParts[ 1 ] );
+
+					if( ( majorVersion == 12 && minorVersion >= 1 ) || majorVersion > 12 ) {
+						limitSB.append(" LIMIT ").append(max);
+						limitSB.append(" OFFSET ").append(firstIndex);
+					}
+					else {
+						querySB.insert( 0, "SELECT * FROM ( " );
+						limitSB.append( " ) WHERE rownum BETWEEN " )
+						.append( firstIndex + 1 )
+						.append( " AND " )
+						.append( firstIndex + max );
+					}
+				} catch( SQLException e ) {
+					Log.warn( "Unable to determine oracle database version using fallback", e );
+					querySB.insert( 0, "SELECT * FROM ( " );
+					limitSB.append( " ) WHERE rownum BETWEEN " )
+					.append( firstIndex + 1 )
+					.append( " AND " )
+					.append( firstIndex + max );
+				}
+			}
 			else {
 				limitSB.append(" LIMIT ").append(max);
 				limitSB.append(" OFFSET ").append(firstIndex);
@@ -487,6 +518,11 @@ public class JdbcPersistenceManager implements PersistenceManager {
 		return archivedMessages.values();
 	}
 
+	private boolean isOracleDB()
+	{
+		return DbConnectionManager.getDatabaseType() == DbConnectionManager.DatabaseType.oracle;
+	}
+
 	private Integer countMessages(Date startDate, Date endDate,
 			String ownerJid, String withJid, String whereClause) {