WorldEdit is a voxel and block manipulation library for Minecraft. It is primarily a library but bindings to Bukkit (included) and SPC (external) are available.

Compiling

You need to have Maven installed (http://maven.apache.org). Once installed, simply run:

mvn clean package install

Maven will automatically download dependencies for you. Note: For that to work, be sure to add Maven to your "PATH".

Contributing

We happily accept contributions. The best way to do this is to fork WorldEdit on GitHub, add your changes, and then submit a pull request. We'll look at it, make comments, and merge it into WorldEdit if everything works out.

Your submissions have to be licensed under the GNU General Public License v3.

General Concepts

The entry point for all of WorldEdit is in com.sk89q.worldedit.WorldEdit. This is where all the events and chat commands are handled. The commands themselves are found in the com.sk89q.worldedit.commands package.

Each user has a session that stores session-related data, including history and clipboard. The class that handles session data is com.sk89q.worldedit.LocalSession. A copy of it is created when needed by the getSession method of WorldEdit and it's also stored on WorldEdit in a hash map. The history is merely a list of com.sk89q.worldedit.EditSessions, while the clipboard is a copy of com.sk89q.worldedit.CuboidClipboard.

Now, one of the most important classes in WorldEdit is com.sk89q.worldedit.EditSession. Nearly all block sets and gets are routed through it because it automatically records a log of operations (for undo), handles block placement order, and does a lot of magic to make sure things come out the way it is intended. However, to make sure that block placement order is adhered, remember to call EditSession.enableQueue() and later EditSession.flushQueue(). Also, to actually an edit session in a player's history, it has to be passed to LocalSession.remember(EditSession).

Blocks in WorldEdit are entirely abstracted. Block types and block data not simply passed around; rather, because blocks can contain a lot more data (such as with signs and such), all blocks are an instance of com.sk89q.worldedit.blocks.BaseBlock. For special block types, there's a SignBlock, a ChestBlock, etc. Blocks are detached from the world, meaning they don't know where they are. You can pass them around freely if you want (this is why syntax like //set sign:3|Hi|there! can work).

If you are making a command, you need to add the new command to plugin.yml if you are using Bukkit. However, com.sk89q.worldedit.dev.DocumentationPrinter is a program that will generate plugin.yml by using Java reflection on the command classes. Commands are given an edit session automatically (with queue enabled) and so there's not much to set up. If you want to add a new class altogether that contains commands, you need to update the constructor of com.sk89q.worldedit.WorldEdit load your class.

Core Routines

com.sk89q.worldedit.WorldEdit.getBlock handles the block syntax (such as sign:3|Hi|there!). com.sk89q.worldedit.WorldEdit.getBlockPattern handles the pattern syntax (such as 90%rock,10%brick or #clipboard).

Package Summary

WorldEdit is well organized and uses abstraction heavily to make adding new things easy. An explanation of WorldEdit's package layout is as follows:

com.sk89q.bukkit.migration has classes to handle permissions for Bukkit plugins until Bukkit attains built-in permissions support
com.sk89q.util has some utility classes
com.sk89q.util.commands has some base command handling code (commands in WorldEdit are defined using Java annotations)
com.sk89q.worldedit has core WorldEdit classes
com.sk89q.worldedit.bags has support for block sources and sinks such as inventory (which allows blocks to be taken from a player's inventory)
com.sk89q.worldedit.blocks abstracts blocks from the game (such as chest blocks, etc.) and has support for all block data
com.sk89q.worldedit.bukkit contains the implementation of WorldEdit for Bukkit as a plugin
com.sk89q.worldedit.commands has all of WorldEdit's chat commands
com.sk89q.worldedit.data contains classes to read Minecraft's world files directly from disk
com.sk89q.worldedit.dev contains a class to generate documentation and other development-related files
com.sk89q.worldedit.filters contains filters used for the smoothing algorithm
com.sk89q.worldedit.patterns contains the pattern support (such as for //set 90%rock,10%air or //set #clipboard)
com.sk89q.worldedit.regions contains the selection regions for WorldEdit; there's only one at the moment (a cuboid), but different region shapes can be added easily
com.sk89q.worldedit.scripting contains scripting engines
com.sk89q.worldedit.snapshots contains snapshot loading code (but actual world file reading code is in com.sk89q.worldedit.data)
com.sk89q.worldedit.superpickaxe contains the code for the different super pickaxe modes
com.sk89q.worldedit.superpickaxe.brush contains the different brush shapes for the brush super pickaxe tools
com.sk89q.worldedit.util has some utility classes
org.jnbt is the JNBT library to read JNBT formatted files

Task Tutorials

How to Add a Command

If you want to add your command to an existing category of commands (check out the classes in com.sk89q.worldedit.commands) then you can just re-use one. If you want to create a new class, create a new class (it does not have to inherit or implement anything) and add it to the constructor of com.sk89q.worldedit.WorldEdit.
Add a new method, named anything.
Add the @Command annotation to signify that it is a command. The aliases property contains a list of command aliases and the first one in the list is the main alias. usage contains parameter usage information. desc is a short description. flags is an optional string of flags (each flag is only one character long). min is the minimum number of arguments. max is the maximum number of arguments and it can be -1 to allow an unlimited number.
Adding @CommandPermissions causes permissions to be checked for the command. Only one permission needs to be satisfied in the list.
Write the command.
If using Bukkit, update plugin.yml or run com.sk89q.worldedit.dev.DocumentationPrinter to generate it for you.
Compile and test!