Convert Velocity buildscripts to Kotlin DSL (#918)

Spiritually indebted to #518 and @alexstaeding.

There's a minor break - we're going up to 3.2.0-SNAPSHOT as the API now compiles against Java 11. But this is more academic in practice.

api/build.gradle.kts

@@ -0,0 +1,80 @@
+plugins {
+    `java-library`
+    `maven-publish`
+}
+
+license {
+    header(project.file("HEADER.txt"))
+}
+
+java {
+    withJavadocJar()
+    withSourcesJar()
+
+    sourceSets["main"].java {
+        srcDir("src/ap/java")
+    }
+}
+
+val gsonVersion: String by project.extra
+val guiceVersion: String by project.extra
+val guavaVersion: String by project.extra
+val adventureVersion: String by project.extra
+val slf4jVersion: String by project.extra
+val checkerFrameworkVersion: String by project.extra
+val configurateVersion: String by project.extra
+
+dependencies {
+    api("com.google.code.gson:gson:$gsonVersion")
+    api("com.google.guava:guava:$guavaVersion")
+
+    // DEPRECATED: Will be removed in Velocity Polymer
+    api("com.moandjiezana.toml:toml4j:0.7.2")
+
+    api(platform("net.kyori:adventure-bom:${adventureVersion}"))
+    api("net.kyori:adventure-api")
+    api("net.kyori:adventure-text-serializer-gson")
+    api("net.kyori:adventure-text-serializer-legacy")
+    api("net.kyori:adventure-text-serializer-plain")
+    api("net.kyori:adventure-text-minimessage")
+
+    api("org.slf4j:slf4j-api:$slf4jVersion")
+    api("com.google.inject:guice:$guiceVersion")
+    api("org.checkerframework:checker-qual:${checkerFrameworkVersion}")
+    api("com.velocitypowered:velocity-brigadier:1.0.0-SNAPSHOT")
+
+    api("org.spongepowered:configurate-hocon:${configurateVersion}")
+    api("org.spongepowered:configurate-yaml:${configurateVersion}")
+    api("org.spongepowered:configurate-gson:${configurateVersion}")
+}
+
+tasks {
+    jar {
+        manifest {
+            attributes["Automatic-Module-Name"] = "com.velocitypowered.api"
+        }
+    }
+    withType<Javadoc> {
+        exclude("com/velocitypowered/api/plugin/ap/**")
+
+        val o = options as StandardJavadocDocletOptions
+        o.encoding = "UTF-8"
+        o.source = "8"
+
+        o.links(
+                "https://www.slf4j.org/apidocs/",
+                "https://guava.dev/releases/$guavaVersion/api/docs/",
+                "https://google.github.io/guice/api-docs/$guiceVersion/javadoc/",
+                "https://docs.oracle.com/en/java/javase/11/docs/api/",
+                "https://jd.adventure.kyori.net/api/$adventureVersion/"
+        )
+
+        // Disable the crazy super-strict doclint tool in Java 8
+        o.addStringOption("Xdoclint:none", "-quiet")
+
+        // Remove "undefined" from search paths when generating javadoc for a non-modular project (JDK-8215291)
+        if (JavaVersion.current() >= JavaVersion.VERSION_1_9 && JavaVersion.current() < JavaVersion.VERSION_12) {
+            o.addBooleanOption("-no-module-directories", true)
+        }
+    }
+}

api/src/ap/java/com/velocitypowered/api/plugin/ap/PluginAnnotationProcessor.java

@@ -27,6 +27,9 @@
 import javax.tools.FileObject;
 import javax.tools.StandardLocation;
 
+/**
+ * Annotation processor for Velocity.
+ */
 @SupportedAnnotationTypes({"com.velocitypowered.api.plugin.Plugin"})
 public class PluginAnnotationProcessor extends AbstractProcessor {
 

api/src/ap/java/com/velocitypowered/api/plugin/ap/SerializedPluginDescription.java

@@ -19,6 +19,9 @@
 import java.util.stream.Collectors;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+/**
+ * Serialized version of {@link com.velocitypowered.api.plugin.PluginDescription}.
+ */
 public final class SerializedPluginDescription {
 
   public static final Pattern ID_PATTERN = Pattern.compile("[a-z][a-z0-9-_]{0,63}");
@@ -130,6 +133,9 @@ public String toString() {
         + '}';
   }
 
+  /**
+   * Represents a dependency.
+   */
   public static final class Dependency {
 
     private final String id;

api/src/main/java/com/velocitypowered/api/command/CommandManager.java

@@ -84,6 +84,7 @@ default void register(String alias, Command command, String... otherAliases) {
 
   /**
    * Retrieves the {@link CommandMeta} from the specified command alias, if registered.
+   *
    * @param alias the command alias to lookup
    * @return an {@link CommandMeta} of the alias
    */

api/src/main/java/com/velocitypowered/api/event/command/CommandExecuteEvent.java

@@ -29,6 +29,7 @@ public final class CommandExecuteEvent implements ResultedEvent<CommandResult> {
 
   /**
    * Constructs a CommandExecuteEvent.
+   *
    * @param commandSource the source executing the command
    * @param command the command being executed without first slash
    */
@@ -43,7 +44,8 @@ public CommandSource getCommandSource() {
   }
 
   /**
-   * Gets the original command being executed without first slash.
+   * Gets the original command being executed without the first slash.
+   *
    * @return the original command being executed
    */
   public String getCommand() {
@@ -108,6 +110,7 @@ public String toString() {
 
     /**
      * Allows the command to be sent, without modification.
+     *
      * @return the allowed result
      */
     public static CommandResult allowed() {
@@ -116,14 +119,17 @@ public static CommandResult allowed() {
 
     /**
      * Prevents the command from being executed.
+     *
      * @return the denied result
      */
     public static CommandResult denied() {
       return DENIED;
     }
 
     /**
-     * Prevents the command from being executed, but forward command to server.
+     * Forwards the command to server instead of executing it on the proxy. This is the
+     * default behavior when a command is not registered on Velocity.
+     *
      * @return the forward result
      */
     public static CommandResult forwardToServer() {
@@ -132,6 +138,7 @@ public static CommandResult forwardToServer() {
 
     /**
      * Prevents the command from being executed on proxy, but forward command to server.
+     *
      * @param newCommand the command without first slash to use instead
      * @return a result with a new command being forwarded to server
      */
@@ -141,7 +148,9 @@ public static CommandResult forwardToServer(@NonNull String newCommand) {
     }
 
     /**
-     * Allows the command to be executed, but silently replaced old command with another.
+     * Allows the command to be executed, but silently replaces the command with a different
+     * command.
+     *
      * @param newCommand the command to use instead without first slash
      * @return a result with a new command
      */

api/src/main/java/com/velocitypowered/api/event/command/PlayerAvailableCommandsEvent.java

@@ -29,6 +29,7 @@ public class PlayerAvailableCommandsEvent {
 
   /**
    * Constructs an available commands event.
+   *
    * @param player the targeted player
    * @param rootNode the Brigadier root node
    */

api/src/main/java/com/velocitypowered/api/event/connection/DisconnectEvent.java

@@ -51,6 +51,9 @@ public String toString() {
         + '}';
   }
 
+  /**
+   * The status of the connection when the player disconnected.
+   */
   public enum LoginStatus {
 
     SUCCESSFUL_LOGIN,

api/src/main/java/com/velocitypowered/api/event/connection/PreLoginEvent.java

@@ -37,6 +37,7 @@ public final class PreLoginEvent implements ResultedEvent<PreLoginEvent.PreLogin
 
   /**
    * Creates a new instance.
+   *
    * @param connection the connection logging into the proxy
    * @param username the player's username
    */

api/src/main/java/com/velocitypowered/api/event/player/GameProfileRequestEvent.java

@@ -35,6 +35,7 @@ public final class GameProfileRequestEvent {
 
   /**
    * Creates a new instance.
+   *
    * @param connection the connection connecting to the proxy
    * @param originalProfile the original {@link GameProfile} for the user
    * @param onlineMode whether or not the user connected in online or offline mode

api/src/main/java/com/velocitypowered/api/event/player/KickedFromServerEvent.java

@@ -35,6 +35,7 @@ public final class KickedFromServerEvent implements
 
   /**
    * Creates a {@code KickedFromServerEvent} instance.
+   *
    * @param player the player affected
    * @param server the server the player disconnected from
    * @param originalReason the reason for being kicked, optional

api/src/main/java/com/velocitypowered/api/event/player/PlayerChatEvent.java

@@ -28,6 +28,7 @@ public final class PlayerChatEvent implements ResultedEvent<PlayerChatEvent.Chat
 
   /**
    * Constructs a PlayerChatEvent.
+   *
    * @param player the player sending the message
    * @param message the message being sent
    */
@@ -96,6 +97,7 @@ public String toString() {
 
     /**
      * Allows the message to be sent, without modification.
+     *
      * @return the allowed result
      */
     public static ChatResult allowed() {
@@ -104,14 +106,16 @@ public static ChatResult allowed() {
 
     /**
      * Prevents the message from being sent.
+     *
      * @return the denied result
      */
     public static ChatResult denied() {
       return DENIED;
     }
 
     /**
-     * Allows the message to be sent, but silently replaced with another.
+     * Allows the message to be sent, but silently replaces it with another.
+     *
      * @param message the message to use instead
      * @return a result with a new message
      */

api/src/main/java/com/velocitypowered/api/event/player/PlayerChooseInitialServerEvent.java

@@ -28,6 +28,7 @@ public class PlayerChooseInitialServerEvent {
 
   /**
    * Constructs a PlayerChooseInitialServerEvent.
+   *
    * @param player the player that was connected
    * @param initialServer the initial server selected, may be {@code null}
    */
@@ -46,9 +47,10 @@ public Optional<RegisteredServer> getInitialServer() {
 
   /**
    * Sets the new initial server.
+   *
    * @param server the initial server the player should connect to
    */
-  public void setInitialServer(RegisteredServer server) {
+  public void setInitialServer(@Nullable RegisteredServer server) {
     this.initialServer = server;
   }