Example
There are frequent behavior patterns that can result in a lot of boilerplate code. By declaring a method that takes a Closure as a parameter, you can simplify your program. As an example, it is a common pattern to retrieve a database connection, start a transaction, do work, and then either commit the transaction, or rollback the connection (in case of error), then finally close the connection:
def withConnection( String url, String user, String pass, Closure closure) {
Connection conn = null
try {
conn = DriverManager.getConnection( url, user, pass )
closure.call( conn )
conn.commit()
} catch (Exception e) {
log.error( "DB Action failed", e)
conn.rollback()
} finally {
conn?.close()
}
}
withConnection( DB_PATH, DB_USER, DB_PASS ) { Connection conn ->
def statement = conn.createStatement()
def results = statement.executeQuery( 'SELECT * FROM users' )
// ... more processing ...
}
