refactor: move a lot of methods to visibility modifier (#299)

src/main/java/minevalley/core/api/Core.java

@@ -24,7 +24,7 @@
 import minevalley.core.api.regions.structures.Street;
 import minevalley.core.api.regions.utils.Area;
 import minevalley.core.api.regions.utils.Boundary;
-import minevalley.core.api.regions.utils.FakeBlock;
+import minevalley.core.api.utils.FakeBlock;
 import minevalley.core.api.server.Server;
 import minevalley.core.api.team.Team;
 import minevalley.core.api.timing.Reminder;

src/main/java/minevalley/core/api/CoreServer.java

@@ -24,7 +24,7 @@
 import minevalley.core.api.regions.structures.Street;
 import minevalley.core.api.regions.utils.Area;
 import minevalley.core.api.regions.utils.Boundary;
-import minevalley.core.api.regions.utils.FakeBlock;
+import minevalley.core.api.utils.FakeBlock;
 import minevalley.core.api.server.Server;
 import minevalley.core.api.team.Team;
 import minevalley.core.api.timing.Reminder;

src/main/java/minevalley/core/api/modifiers/VisibilityModifier.java

@@ -1,20 +1,74 @@
 package minevalley.core.api.modifiers;
 
 import minevalley.core.api.users.OnlineUser;
+import org.jetbrains.annotations.Contract;
 
+import javax.annotation.Nonnull;
 import java.util.function.Function;
 
 @SuppressWarnings("unused")
 public interface VisibilityModifier {
 
     /**
-     * Defines who can see this object
+     * Shows this object to everyone who can see it.
+     * <p>
+     * <b>Note:</b>
+     * <ul>
+     *     <li>Objects are by default visible when created (no need to call this method, if the object was not hidden actively before)</li>
+     *     <li>Hidden objects can be modified (lines of holograms, name of npc, ...). Changes will be visible after calling show()</li>
+     * </ul>
+     *
+     * @throws IllegalStateException if the object is already visible
+     * @see #isVisible()
+     */
+    void show() throws IllegalStateException;
+
+    /**
+     * Hide this object from everyone who can see it.
+     * <p>
+     * <b>Note:</b>
+     * <ul>
+     *     <li>Hiding objects removes them completely and for everyone from the map</li>
+     *     <li>Hiding is not permanent: Objects can be made visible again by calling {@link #show()}</li>
+     *     <li>Hidden objects can be modified (lines of holograms, name of npc, ...). Changes will be visible after calling show()</li>
+     * </ul>
+     *
+     * @throws IllegalStateException if the object is already hidden
+     * @see #isVisible()
+     */
+    void hide() throws IllegalStateException;
+
+    /**
+     * Returns whether this object is visible
+     *
+     * @return true if this object is visible, false otherwise
+     */
+    @Contract(pure = true)
+    boolean isVisible();
+
+    /**
+     * Defines who can see this object.
+     * <p>
+     * <b>Note:</b>
+     * <ul>
+     *     <li>Setting the visibility replaces the previous visibility function</li>
+     *     <li>Objects are only visible if {@link #isVisible()} is true (which is the default state)</li>
+     * </ul>
      * <br>
      * <b>Default:</b> Everyone can see this object
      *
-     * @param function defines whether a specific user can see this object
+     * @param visibility defines whether a specific user can see this object
+     * @throws IllegalArgumentException if visibility is null
+     * @see #isVisible()
+     */
+    void setVisibility(@Nonnull Function<OnlineUser, Boolean> visibility) throws IllegalArgumentException;
+
+    /**
+     * Sets the visibility of this object to everyone.
      */
-    void setVisibility(Function<OnlineUser, Boolean> function);
+    default void setVisibleToEveryone() {
+        setVisibility(user -> true);
+    }
 
     /**
      * Updates the visibility of this object
@@ -29,6 +83,7 @@ public interface VisibilityModifier {
      * <b>Note:</b> This simply calls the function defined in {@link #setVisibility(Function)} for this user
      *
      * @param user to update the visibility for
+     * @throws IllegalArgumentException if user is null
      */
-    void updateVisibility(OnlineUser user);
+    void updateVisibility(@Nonnull OnlineUser user) throws IllegalArgumentException;
 }

src/main/java/minevalley/core/api/npc/NPC.java

@@ -81,8 +81,6 @@ default void zoomIn(OnlineUser user) {
 
     Location getLocation();
 
-    void remove();
-
     boolean isNameTagHidden();
 
     void hideNameTag(boolean hidden);

src/main/java/minevalley/core/api/utils/CarBarrier.java

@@ -1,7 +1,9 @@
 package minevalley.core.api.utils;
 
+import minevalley.core.api.modifiers.VisibilityModifier;
+
 @SuppressWarnings("unused")
-public interface CarBarrier {
+public interface CarBarrier extends VisibilityModifier {
 
     /**
      * Opens the barrier.
@@ -16,11 +18,4 @@ public interface CarBarrier {
      * @throws IllegalStateException if the barrier is already closed or removed.
      */
     void close() throws IllegalStateException;
-
-    /**
-     * Removes the barrier.
-     *
-     * @throws IllegalStateException if the barrier is already removed.
-     */
-    void remove() throws IllegalStateException;
 }

src/main/java/minevalley/core/api/utils/FakeBlock.java

@@ -0,0 +1,27 @@
+package minevalley.core.api.utils;
+
+import minevalley.core.api.modifiers.VisibilityModifier;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+
+import javax.annotation.Nonnull;
+
+@SuppressWarnings("unused")
+public interface FakeBlock extends VisibilityModifier {
+
+    /**
+     * Get the block this fake block is placed on
+     *
+     * @return the block this fake block is placed on
+     */
+    @Nonnull
+    Block getBlock();
+
+    /**
+     * Get the material of this fake block
+     *
+     * @return the material of this fake block
+     */
+    @Nonnull
+    Material getMaterial();
+}

src/main/java/minevalley/core/api/utils/Hologram.java

@@ -6,21 +6,52 @@
 @SuppressWarnings("unused")
 public interface Hologram extends LocationModifier, VisibilityModifier {
 
+    /**
+     * Returns the lines of the hologram.
+     *
+     * @return the lines of the hologram.
+     */
     String[] getLines();
 
+    /**
+     * Returns the line at the specified index.
+     *
+     * @param line the index of the line.
+     * @return the line at the specified index.
+     */
     default String getLine(int line) {
         return getLines()[line];
     }
 
+    /**
+     * Adds a line to the hologram.
+     *
+     * @param text the text of the line.
+     */
     default void addLine(String text) {
         addLineAfter(getLines().length - 1, text);
     }
 
+    /**
+     * Adds a line to the hologram at the specified index.
+     *
+     * @param line the index of the line.
+     * @param text the text of the line.
+     */
     void addLineAfter(int line, String text);
 
+    /**
+     * Changes the line at the specified index.
+     *
+     * @param line the index of the line.
+     * @param text the new text of the line.
+     */
     void changeLine(int line, String text);
 
+    /**
+     * Removes the line at the specified index.
+     *
+     * @param line the index of the line.
+     */
     void removeLine(int line);
-
-    void delete();
 }