SPIGOT-7540, #946: Add ServerTickManager API

By: Miles Holder <mwholder2005@gmail.com>

paper-api/src/main/java/org/bukkit/Bukkit.java

@@ -280,6 +280,16 @@ public final class Bukkit {
         return server.getDataPackManager();
     }
 
+    /**
+     * Get the ServerTick Manager.
+     *
+     * @return the manager
+     */
+    @NotNull
+    public static ServerTickManager getServerTickManager() {
+        return server.getServerTickManager();
+    }
+
     /**
      * Gets the server resource pack uri, or empty string if not specified.
      *

paper-api/src/main/java/org/bukkit/Server.java

@@ -239,6 +239,14 @@ public interface Server extends PluginMessageRecipient {
     @NotNull
     public DataPackManager getDataPackManager();
 
+    /**
+     * Get the ServerTick Manager.
+     *
+     * @return the manager
+     */
+    @NotNull
+    public ServerTickManager getServerTickManager();
+
     /**
      * Gets the server resource pack uri, or empty string if not specified.
      *

paper-api/src/main/java/org/bukkit/ServerTickManager.java

@@ -0,0 +1,128 @@
+package org.bukkit;
+
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Manages ticking within a server.
+ * <p>
+ * To learn more about the features surrounding this interface.
+ *
+ * @see <a href="https://minecraft.wiki/w/Commands/tick">Tick Command</a>
+ */
+@ApiStatus.Experimental
+public interface ServerTickManager {
+
+    /**
+     * Checks if the server is running normally.
+     * <p>
+     * When the server is running normally it indicates that the server is not
+     * currently frozen.
+     *
+     * @return true if the server is running normally, otherwise false
+     */
+    boolean isRunningNormally();
+
+    /**
+     * Checks if the server is currently stepping.
+     *
+     * @return true if stepping, otherwise false
+     */
+    boolean isStepping();
+
+    /**
+     * Checks if the server is currently sprinting.
+     *
+     * @return true if sprinting, otherwise false
+     */
+    boolean isSprinting();
+
+    /**
+     * Checks if the server is currently frozen.
+     *
+     * @return true if the server is frozen, otherwise false
+     */
+    boolean isFrozen();
+
+    /**
+     * Gets the current tick rate of the server.
+     *
+     * @return the current tick rate of the server
+     */
+    float getTickRate();
+
+    /**
+     * Sets the tick rate of the server.
+     * <p>
+     * The normal tick rate of the server is 20. No tick rate below 1.0F or
+     * above 10,000 can be applied to the server.
+     *
+     * @param tick the tick rate to set the server to
+     * @throws IllegalArgumentException if tick rate is too low or too high for
+     * the server to handle
+     */
+    void setTickRate(float tick);
+
+    /**
+     * Sets the server to a frozen state that does not tick most things.
+     *
+     * @param frozen true to freeze the server, otherwise false
+     */
+    void setFrozen(boolean frozen);
+
+    /**
+     * Steps the game a certain amount of ticks if the server is currently
+     * frozen.
+     * <p>
+     * Steps occur when the server is in a frozen state which can be started by
+     * either using the in game /tick freeze command or the
+     * {@link #setFrozen(boolean)} method.
+     *
+     * @param ticks the amount of ticks to step the game for
+     * @return true if the game is now stepping. False if the game is not frozen
+     * so the request could not be fulfilled.
+     */
+    boolean stepGameIfFrozen(int ticks);
+
+    /**
+     * Stops the current stepping if stepping is occurring.
+     *
+     * @return true if the game is no-longer stepping. False if the server was
+     * not stepping or was already done stepping.
+     */
+    boolean stopStepping();
+
+    /**
+     * Attempts to initiate a sprint, which executes all server ticks at a
+     * faster rate then normal.
+     *
+     * @param ticks the amount of ticks to sprint for
+     * @return true if a sprint was already initiated and was stopped, otherwise
+     * false
+     */
+    boolean requestGameToSprint(int ticks);
+
+    /**
+     * Stops the current sprint if one is currently happening.
+     *
+     * @return true if the game is no-longer sprinting, false if the server was
+     * not sprinting or was already done sprinting
+     */
+    boolean stopSprinting();
+
+    /**
+     * Checks if a given entity is frozen.
+     *
+     * @param entity the entity to check if frozen.
+     * @return true if the entity is currently frozen otherwise false.
+     */
+    boolean isFrozen(@NotNull Entity entity);
+
+    /**
+     * Gets the amount of frozen ticks left to run.
+     *
+     * @return the amount of frozen ticks left to run
+     */
+    int getFrozenTicksToRun();
+}