Java Reference
In-Depth Information
L
ISTING
7.10
Continued
// empty the pool
pool.emptyPool();
// Remove the Attribute from the ServletContext
context.removeAttribute(“CONNECTION_POOL”);
}
else {
System.err.println(“Could not get a reference to Pool!”);
7
}
}
//Get Servlet information
public String getServletInfo() {
return “ConnectionPoolServlet Information”;
}
}
The two areas of the
ConnectionPoolServlet
that you need to examine are the
init()
and
destroy()
methods. The
doGet()
method is just a placeholder; it has no functionality.
The
ConnectionPoolServlet.init()
method creates the
ConnectionPool
and makes it avail-
able to the other servlets. It does this by first creating an instance of the
ConnectionPool
just
like any other application would. It then takes the newly created
ConnectionPool
object and
adds it to the shared
ServletContext
. It does this in the following code snippet:
// Once the pool is Initialized, add it to the
// Global ServletContext. This makes it available
// To other servlets using the same ServletContext.
ServletContext context = getServletContext();
context.setAttribute(“CONNECTION_POOL”, pool);
The preceding code gets a reference to the
ServletContext
, which is shared by all servlets
that exist in the same
ServletContext
. It then calls the
setAttribute()
method, passing it a
string that represents a key and a reference to the
ConnectionPool
object. This makes the
ConnectionPool
available to other servlets.
The
destroy()
method does just the opposite. It first gets a reference to the
ConnectionPool
by calling the
ServletContext.getAttribute()
method. The signature for this method is as
follows:
public java.lang.Object getAttribute(java.langString name)
