Java Examples in a Nutshell, 3rd Edition

Using the API Database

Example 18-4 displays a program, LookupAPI, that uses the database built by the MakeAPIDB program of Example 18-3 and makes interesting SQL queries against it. LookupAPI behaves as follows:

• When invoked with the name of a class member, it lists the full name (including package and class) of each field and/or method that has that name.

• When run with the name of a class, it lists the full name of every class in any package that has that name.

• When called with a portion of a package name, it lists the names of all the packages that contain that string.

• When invoked with the -l option and a class name, it lists every member of every class that has that name.

• When run with the -l option and a portion of a package name, it lists all the classes and interfaces in any package that matches that string.

LookupAPI reads the same APIDB.props property file MakeAPIDB does. Or, alternatively, it reads a property file specified on the command line following a -p flag. Using the database connection parameters in the property file, the program connects to a database and executes the necessary SQL queries to return the desired information. Note that it calls the setReadOnly( ) method of the Connection object. Doing this provides a hint that the program performs only queries and doesn’t modify the database in any way. For some database systems, this may improve efficiency. Other than the setReadOnly( ) method, this example doesn’t introduce any new JDBC features. It simply ...