When I first wrote an article about changing Oracle concrete classes to interfaces to work with Application Continuity (AC) (https://blogs.oracle.com/WebLogicServer/entry/using_oracle_jdbc_type_interfaces), I left out one type. oracle.sql.OPAQUE is replaced with oracle.jdbc.OracleOpaque. There isn’t a lot that you can do with this opaque type. While the original class had a lot of conversion methods, the new Oracle type interfaces have only methods that are considered significant or not available with standard JDBC API’s. The new interface only has a method to get the value as an Object and two meta information methods to get meta data and type name. Unlike the other Oracle type
interfaces (oracle.jdbc.OracleStruct extends java.sql.Struct and oracle.jdbc.OracleArray extends java.sql.Array), oracle.jdbc.OracleOpaque does not extend aJDBC interface
There is one related very common use case that needs to be changed to work with AC. Early uses of SQLXML made use of the following XDB API.
SQLXML sqlXml = oracle.xdb.XMLType.createXML(((oracle.jdbc.OracleResultSet)resultSet).getOPAQUE(“issue”));
oracle.xdb.XMLType extends oracle.sql.OPAQUE and its use will disable AC replay. This must be replaced with the standard JDBC API
SQLXML sqlXml = resultSet.getSQLXML(“issue”);
If you try to do a “new oracle.xdb.XMLType(connection, string)” when running with the replay datasource, you will get a ClassCastException. Since XMLType doesn’t work with the replay datasource and the oracle.xdb package uses XMLType extensively, this package is no longer usable for AC replay.
The API’s for SQLXML are documented at https://docs.oracle.com/javase/7/docs/api/java/sql/SQLXML.html. The javadoc shows API’s to work with DOM, SAX, StAX, XLST, and XPath.
Take a look at the sample program at this attachment .
The sample uses StAX to store the information and DOM to get it. By default, it uses the replay datasource and it does not use XDB.
You can run with replay debugging by doing something like the following. Create a file named /tmp/config.txt that has the following text.
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
handlers = java.util.logging.FileHandler
java.util.logging.FileHandler.pattern = /tmp/replay.log
oracle.jdbc.internal.replay.level = FINEST
Change your WLS CLASSPATH (or one with the Oracle client jar files) to put ojdbc8_g.jar at the front (to replace ojdbc8.jar) and add the current directory.
Compile the program (after renaming .txt to .java) and run it using
java -Djava.util.logging.config.file=/tmp/config.txt XmlSample
The output replay log is in /tmp/replay.log. With the defaults in the sample program, you won’t see replay disabled in the log. If you change the program to set useXdb to true, you will see that replay is disabled. The log will have “DISABLE REPLAY in preForMethodWithConcreteClass(getOPAQUE)” and “Entering disableReplayInternal”.
This sample can be used to test other sequences of operations to see if they are safe for replay.
Alternatively, you can use orachk to do a static analysis of the class. See https://blogs.oracle.com/WebLogicServer/entry/using_orachk_to_clean_up for more information. If you run orachk
on this program, you will get this failure.
FAILED – [XmlSample][[MethodCall] desc= (Ljava/lang/String;)Loracle/sql/OPAQUE; method name=getOPAQUE, lineno=105]