Skip to main content

What is Apache Maven?



Apache Maven is a cool java project management tool that I recently came across at work. I was asked to set-up a test suite for our low latency Market Data System project using an existing test framework built using TestNG. I was handed over something called a pom.xml file and that was it! Using IntelliJ IDE you can import this pom.xml as a Maven project and everything is basically set-up for you. The folder structure is pretty standard in Maven so that every developer get the same same project structure. I think the main advantage of maven is that it is a great way of managing dependencies. Imagine that something changes in the the so called test framework. The framework developers update the repository and when I re-export the pom file updates the correct jar file will already be in my project. By changing the SNAPSHOT version of the pom.xml file I can switch through different versions of the test framework and other dependencies. Maven will first look for dependencies in the internal repository and then go for global repository to find the specified dependencies. You can set different configurations in the POM file, per user or globally using different settings files.

The other cool thing is the maven's ability to easily invoke TestNG test suites. Maven is reliant on plug-ins which are configured appropriately via the pom file. For example a maven project has a default life-cycle with different phases such as compile, test, package, deploy etc. Each plug-in can be configured with one or more goals to be executed. We call it a mojo. A mojo is a Maven plain Old Java Object!!! Each mojo is an executable goal in Maven, and a plug-in is a distribution of one or more related mojos. For example the test phase plug-in is called surefire.


For our work, we didn't really use all the life cycle phases of maven because we only really needed to run the TestNG test suite as the Market Data System was written in C++ and was running on back-end servers. Separate connections has to be made to these back-end via the test framework to enable testing. However it will be pretty cool if a fully fledged end-to-end project can be built for java based project with all the TestNG unit tests integrated and you can end up with deploying your jar to the client using the deploy plug-in! (Note that mvn-test in the image should point to test phase not package in the image)

Labels

Labels:

Comments

Post a Comment

Popular posts from this blog

Detaching a process from terminal - exec(), system(), setsid() and nohup

Linux processes are created by fork() and exec(). The very first process of POSIX systems is init and subsequent processes are derived from the init as parent. These subsequent processes are child processes. During forking the parent process copies itself - with all I/O, address space, stack, everything. The only thing that is different is the process ID. The parent and child will have 2 different process IDs. The system() library function uses fork(2) to create a child process that executes the shell command specified in command using execl(3) as follows: execl("/bin/sh", "sh", "-c", command, (char *) 0); system() returns after the command has been completed. system() executes a command specified in command by calling /bin/sh -c command , and returns after the command has been completed. During execution of the command, SIGCHLD will be blocked, and SIGINT and SIGQUIT will be ignored.  system() calls are often made within programs to execut...
Post a Comment
Read more

C++ Callbacks using function pointers vs boost bind +boost function

In C, the most common uses of callbacks are as parameters to library functions like qsort , and as callbacks for Windows functions, etc. For example you might have a library that provides some sorting functions but you want to allow the library user to provide his own sorting function. Since the arguments and the return values do not change depending on the sorting algorithm, this can be facilitated in a convenient manner using function callbacks. Callbacks are also used as event listeners. onMouseClick(), onTerminalInput(), onData(), onConnectionStatus(), onRead() are probably some examples you've already seen in different libraries. The libraries have these callback functions and the users of the library are supposed to implement them. The library has a function pointer to these functions and calls them on their event loop which will invoke the code of the inherited classes of the library user. The implementation of function pointers is simple: they are just "code p...
Post a Comment
Read more

sprintf, snprintf, strcpy, strncpy and sizeof operator

"C library functions such as strcpy (), strcat (), sprintf () and vsprintf () operate on null terminated strings and perform no bounds checking." "snprintf is safer than sprintf" What do these statements really mean? int sprintf ( char * str , const char * format , ... )  int snprintf ( char * s, size_t n, const char * format, ... );  char * strcpy ( char * destination, const char * source ); char * strncpy ( char * destination, const char * source, size_t num );   The usage is something like; char* msg1 = new char[10]; strcpy(msg1, "test"); // 1 char buffer[128]; sprintf(buffer, "%s", msg); //2 strcpy : Copies bytes until it finds a 0-byte in the source code. The string literal "test" has 4 characters and a terminating null character at end, therefore needs 5 characters at least on msg1.  Is this dangerous? Yes, because if the source message is not null terminated it will read until a null character ...
Post a Comment
Read more