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1. #INSTALL PLUGINS BLOCS APP UPDATE#
2. #INSTALL PLUGINS BLOCS APP SOFTWARE#
3. #INSTALL PLUGINS BLOCS APP CODE#

For server applications in particular this would be unfeasible, especially in a production setting.

#INSTALL PLUGINS BLOCS APP UPDATE#

With a bit more work one could allow plugins to be added later, i.e., scan the directory again, and add any plugins that weren't there during the previous scan.Ī useful feature is to be able to update plugins without the need to stop and restart the host application.

The easiest way is to do it just once at startup, at which time the plugins haven't been loaded and run yet. One important question to consider is at which time the application scans the directory to discover plugins. The directory will be called ” plugins“, and is located directly inside the main application directory. In this example we confine ourselves to loading plugins from a particular directory on the local hard disk, which is a common way for desktop applications. We need to define how a an application acquires or gets to know about plugins. But for the introductory purposes of this article, we limit ourselves to the interface shown above. E.g., there could be plugins with and without a GUI, or plugins that receive and return more complex types, or that require a more complicated flow of control. Real plugins would likely have methods for initialization and cleanup, and probably more than one functional method.Ī more powerful approach might involve several different interfaces, with differing characteristics and different lifecycle methods. Looking at these calls, it's clear that the plugins are rather limited - there is just a single functional call, which takes an integer parameter and returns an integer result. Which signals that the previous call to the plugin was not successful Through which the application can retrieve the result of the plugins work, i.e. Which lets the hosting application set a parameter for the plugin to work with Which returns the name of the plugin, so that it can be displayed to the user in some way In the example, we require plugins to implement the PluginFunction interface. The methods of the interface can be thought of as ”lifecycle“ methods - operations the host application calls to initialize a plugin, set parameters, execute it, get results and shut it down. In order for the host application to treat all plugins the same way, we define an interface which the plugins need to implement.

#INSTALL PLUGINS BLOCS APP CODE#

write a ClassLoader that loads the plugin classes.determine how the host application gets to know which plugins are available, and where to find them.a Java interface, for the plugin to implement Generally speaking, there are four steps involved in the process. These are atypical, though, and what is described here is more like what Photoshop does.) (Examples of Java plugins in a broader sense would also be the Applet API in web browsers, and the Servlet API in web servers. This article shows how a plugin API can be added to Java applications. While Photoshop plugins are written in C, the mechanism is really language-independent, although it is constrained by the language the host application is written in. One application whose plugin API is very successful is Adobe Photoshop, which even spawned a market for commercially available plugins. One way of doing so is through plugins: chunks of external code that are accessed through the application, and use its API to perform a function that the application itself can't. Another option would be to extend the application by using its API, if it provides one. One solution might be to export the data, work on it with a different application which has the desired functionality, and then re-import it.

#INSTALL PLUGINS BLOCS APP SOFTWARE#

Even worse, it might be something really specialized that only she needs, and which will never be added by the software vendor. No matter how many functions an application has, there are times when a user wants to do something that the original developers have not foreseen, and which is not included in the application.