User talk:Paint Ninja/Installer

see Actions.java, Action.java, ClientInstall/ServerInstall/ExtractAction.java

example with ExtractAction: final Actions action = Actions.EXTRACT;

action.getAction(installProfile, monitor) will refer to the BiFunction<Install, ProgressCallback, Action> action inside the Actions.java enum which Actions.EXTRACT specifically populates as a new instance of ExtractAction.java as the BiFunction (a BiFunction being an Object that takes two inputs, can do some work and has one output).

The Install installProfile and ProgressCallback monitor arguments are then applied to the BiFunction, which causes ExtractAction's constructor to be called with those arguments.

ExtractAction's constructor calls its parent constructor (Action.java) with super(profile, monitor, true). true being isClient here.

Action.java's constructor populates some variables and instantiates PostProcessors.java, which calls the installProfile's getProcessors("client") and getData(true) methods and stores their results in a List<Processor> and a Map<String, String>, respectively. Install#getProcessors() will return an empty list and Install#getData() will return a new, empty HashMap, this is just to set things up for when the action is ran.

action.getAction(installProfile, monitor).run(target, a -> true)

The ExtractAction.java overrides the run(File, Predicate<String>) method. In this case, the args from the run method invocation above provide the target directory to extract to and what's basically an unused truthy boolean value.

This run method returns true if successful and false otherwise. It gets the path variable from the parsed installProfile, which is the Maven artifact path for the 'main' jar and is an instance of Artifact.java.

Artifact.java uses an Adapter subclass that implements a JSON deserializer and serializer that gets the JSON primitive String and calls the Artifact#from(String) to split the maven descriptor into its parts and build a path to it inside the Installer jar.

It then calls DownloadUtils#extractFile(Artifact, File, String) with the Maven artifact path to extract from, the target path to put it in when extracted and a null (meaning don't verify its checksum after extracting it).

Extracting the Artifact is easier than it sounds, it just grabs a file embedded within the jar under the maven folder (similar to how the install_profile.json is obtained) and copies it to the target path, overwriting any existing files there and creating directories to put them in when necessary.

if (action.getAction(installProfile, monitor).run(target, a -> true)) {