Solving the 8 Queens puzzle with bit operations

The 8 queens puzzle is a classic (and quite fun to solve) toy problem: place eight queens on a chess board in such a way that all queens could fully move without being obstructed by any other queen. While without practical applications, it illustrates a number of aspects of designing algorithms and implementing programmes: - … Continue reading Solving the 8 Queens puzzle with bit operations

Connecting with Eclipse to a remote SVN repository via SSH on non-standard ports

Having been bitten by this for the n-th time (with n being subjectively a large integer), I'm noting this down for the following generations to benefit; and hopefully to save myself some fiddling next time it happens. Without further ado: How to connect with SVN to a remote repository that is running on a non-standard … Continue reading Connecting with Eclipse to a remote SVN repository via SSH on non-standard ports

The jsp-file directive

The jsp-file directive in web.xml allows mapping of JSPs to concrete URLs: <servlet> <servlet-name>My Hidden Page</servlet-name> <jsp-file>/mydir/foo.jsp</jsp-file> </servlet> <servlet-mapping> <servlet-name>My Hidden Page</servlet-name> <url-pattern>/hidden</url-pattern> </servlet-mapping> Shame on me, I didn't know about this. As seen here: http://mail-archives.apache.org/mod_mbox/tomcat-users/200107.mbox/%3CPine.BSF.4.21.0107271807540.7976-100000@localhost%3E

Liferay diaries: Help! My validation errors are not showing!

While still battling form submissions in my Liferay/Spring MVC Form controller/Multi-portlet beast, I noticed that the Spring form tags would not display errors. As this post [1] explains, the reason is that the form backing object must be named exactly as the class consituting the backing object, but with the first letter in lowercase. Thus … Continue reading Liferay diaries: Help! My validation errors are not showing!