Overview of Gradle to Manage Dependencies

After getting a decent grasp of how the libraries will be using our bundled as jar 0:00 files, let's now turn to how and where we're going to obtain those libraries. 0:04 And how we'll get them into the class path. 0:09 Now, we could just do a simple web search for a specific jar file we want to use, 0:12 download it, then use an IDE option to add it to the class path. 0:18 If you search for instructions on how to do this for 0:23 a specific library, the Spring Web library, for example, you might be 0:25 surprised to find little guidance on where to manually download this .jar file. 0:29 Even trickier is that if you were to download a .jar file, and 0:34 successfully add it to the class path, you might find that the .jar 0:38 file you downloaded depends on yet another .jar file. 0:41 Now you have to do it all over again. 0:45 And probably not just once, but likely many more times. 0:47 And if you ever wanted to share your project with other developers, 0:50 it'd have to go through the same process. 0:54 If that isn't enough, what happens when you update your application and 0:56 some libraries are left behind while new libraries are added? 1:00 Because of this, most developers use special tools for 1:05 managing what are called dependencies. 1:08 Dependencies of a project are libraries that a project depends on 1:11 in order to function. 1:14 There are a couple big names out there in dependency management tools, 1:16 namely Maven and Gradle. 1:19 We're going to use Gradle to manage our dependencies in this course. 1:22 Fortunately this tool is integrated with IntelliJ, so 1:26 you should be able to use it without installing Gradle separately. 1:29 Using what's called a Gradle build file, we'll be able to list 1:33 the names of the libraries that we want to incorporate into our project. 1:37 Then, with a click of a button, Gradle will download all of the .jar files for 1:40 the libraries we listed and even the libraries our listed ones depend on. 1:45 It's much easier, quicker, and more reliable than the manual download method. 1:50 I don't know about you, but I'm itching to code a little bit. 1:56 Remember how we plan on building an animated gif library called gif lib? 1:59 Let's get that project created in IntelliJ and see Gradle in action. 2:03 To get started let's open IntelliJ and create a new project. 2:08 I'll choose Create New Project from the screen that pops up here. 2:12 From the left hand side, we'll choose Gradle. 2:17 And with Java selected, we'll click Next. 2:19 The GroupId field should be formatted like a root package name. 2:23 I'll use com.teamtreehouse. 2:27 The ArtifactId should be an identifier or project name. 2:31 I'll use giflib. 2:34 And then we shall click Next. 2:37 In the next window, we'll accept all the defaults. 2:40 Notice that the recommended option here is to use the default Gradle wrapper, 2:43 which means Gradle as a program will be included as part of our project. 2:47 Click Next and verify the name and location of your project. 2:51 When you're ready to create it, click Finish. 2:55 Let's expand our project, and take a look at what we have. 2:58 Know that within a few moments, you'll see your project directory expand as 3:02 the Gradle tool is downloaded and added to our project directory. 3:06 The first file we'll look at, is the .iml file. 3:11 As you may know, IntelliJ uses .iml files to manage module settings. 3:14 Though we're seeing, we won't actually edit this file, so 3:19 I will go ahead and close it. 3:22 The settings.gradle file simply contains our root project 3:24 name which we had entered as giflib. 3:28 We also will not edit this file in this course. 3:30 So, I'll go ahead and close that one too. 3:33 The one file we will concern ourselves with is the build.gradle file, 3:35 this is the file I referenced in a previous video where we can list our 3:40 projects dependencies and Gradle will download them for us. 3:43 Let's check out a couple of things in the build file. 3:46 I'll go ahead and hide the tip that's come up in IntelliJ. 3:50 At the top, you see the group inversion we specified when creating the project. 3:53 For now, suffice it to say, that the group inversion allow repositories such as 3:57 the one we'll be using to get our dependencies 4:01 to group related libraries together and track versions. 4:04 Though I'll leave it alone, you can change this at any time you like. 4:08 The apply plug-in line tells Gradle to 4:11 add pre-defined functionality when using Gradle to build our project. 4:14 This particular functionality has been given the short name Java. 4:18 The repository's blog allows us to define one or 4:22 more locations where Gradle should look for the libraries we list. 4:26 We'll use one of the largest public dependency repositories called 4:29 mavenCentral. 4:33 Finally, we see now where we'll actually list the libraries that we'll need. 4:35 It's called, quite intuitively, the dependencies block. 4:39 In the next video we'll replace what's listed and see Gradle in action. 4:43