Accessing a protected variable of PreparedStatement

[Gello Ramello]

Hi, the environment is Java 1.5, Tomcat 5.5, Postgres 8.1, Eclipse
3.1.1 and Windows XP Pro.
I want to create a function that reads PreparedStatement attributes.
The ps is passed as generic object function parameter and then casted
to PreparedStatement. I can access to PreparedMetaData and other
stuffs, but not to the _stmt properties and methods (like QueryString,
query parameters etc). In fact _stmt is a protected property of
PreparedStatement. My question is: why, as seen in debug mode, Eclipse
can access it and all its methods and properties?
How can I access to _stmt?

Thank you.

 

[Daniel Pitts]

Hi, the environment is Java 1.5, Tomcat 5.5, Postgres 8.1, Eclipse
3.1.1 and Windows XP Pro.
I want to create a function that reads PreparedStatement attributes.
The ps is passed as generic object function parameter and then casted
to PreparedStatement. I can access to PreparedMetaData and other
stuffs, but not to the _stmt properties and methods (like QueryString,
query parameters etc). In fact _stmt is a protected property of
PreparedStatement. My question is: why, as seen in debug mode, Eclipse
can access it and all its methods and properties?
How can I access to _stmt?

Thank you.

First, Debuggers have special access.
Second, you can use reflection to access protected properties.
Third, Don't use reflection to access protected properties...

Generally, even if the PreparedStatement has a string property which
holds the "statement", it is actually just a place-holder reference
for a statement that is already compiled on your SQL server. Changing
the stmt at best would have no effect, and at worse would cause
undefined behavior. Its a bad idea to violate access constraints,
even if you are able.

 

[Gello Ramello]

Daniel Pitts ha usato la sua tastiera per scrivere :

Generally, even if the PreparedStatement has a string property which
holds the "statement", it is actually just a place-holder reference
for a statement that is already compiled on your SQL server. Changing
the stmt at best would have no effect, and at worse would cause
undefined behavior. Its a bad idea to violate access constraints,
even if you are able.

Thank you for your answer, indeed I want to read only the "statement",
not to change it or its properties. The goal is to read the sql string
and the parameters passed to the statement itself. Do you know any way
to do the job? Just to abuse of your courtesy ;-)

 

[Robert Klemme]

Daniel Pitts ha usato la sua tastiera per scrivere :

Thank you for your answer, indeed I want to read only the "statement",
not to change it or its properties. The goal is to read the sql string
and the parameters passed to the statement itself. Do you know any way
to do the job? Just to abuse of your courtesy ;-)

Since PreparedStatement is an interface you can as well write wrapper
classes and thusly intercept method calls.

robert

 

[Gello Ramello]

Robert Klemme ha usato la sua tastiera per scrivere :

Since PreparedStatement is an interface you can as well write wrapper classes
and thusly intercept method calls.

Thank you, is just what I've found here:
http://www-128.ibm.com/developerworks/java/library/j-loggable.html

I've just implemented the wrapper taylored to my needs.

Thank you again.