Created a new helper class for tab completers

Author: Despical

src/main/java/me/despical/commandframework/utils/CompleterHelper.java

@@ -0,0 +1,118 @@
+/*
+ * Command Framework - Annotation based command framework
+ * Copyright (C) 2025  Berke Akçen
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package me.despical.commandframework.utils;
+
+import me.despical.commandframework.CommandArguments;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * @author Despical
+ * <p>
+ * Created at 2.12.2025
+ */
+public final class CompleterHelper {
+
+    private final CommandArguments arguments;
+
+    public CompleterHelper(CommandArguments arguments) {
+        this.arguments = arguments;
+    }
+
+    /**
+     * Retrieves the names of all currently online players on the server.
+     * <p>
+     * This method is useful for tab completion suggestions where a list of
+     * player names is required.
+     *
+     * @return An unmodifiable list containing the names of online players.
+     * Returns an empty list if no players are online. Never returns null.
+     */
+    @NotNull
+    @Contract(pure = true)
+    public List<String> playerNames() {
+        return Bukkit.getServer().getOnlinePlayers().stream().map(Player::getName).toList();
+    }
+
+    /**
+     * Copies all elements from the iterable collection of originals to the
+     * collection provided.
+     *
+     * @param <T> the collection of strings
+     * @param index Argument index to search for
+     * @param originals An iterable collection of strings to filter.
+     * @param collection The collection to add matches to
+     * @return the collection provided that would have the elements copied
+     *     into
+     * @throws UnsupportedOperationException if the collection is immutable
+     *     and originals contains a string which starts with the specified
+     *     search string.
+     * @throws IllegalArgumentException if any parameter is null
+     * @throws IllegalArgumentException if originals contains a null element.
+     *     <b>Note: the collection may be modified before this is thrown</b>
+     */
+    @NotNull
+    @Contract(pure = true)
+    public <T extends Collection<String>> T copyMatches(
+        final int index,
+        @NotNull final Iterable<String> originals,
+        @NotNull final T collection
+    ) {
+        String argument = arguments.getArgument(index);
+
+        if (argument == null) {
+            return collection;
+        }
+
+        return StringUtil.copyPartialMatches(argument, originals, collection);
+    }
+
+    /**
+     * Copies all elements from the iterable collection of originals to the
+     * collection provided.
+     *
+     * @param <T> the collection of strings
+     * @param token String to search for
+     * @param originals An iterable collection of strings to filter.
+     * @param collection The collection to add matches to
+     * @return the collection provided that would have the elements copied
+     *     into
+     * @throws UnsupportedOperationException if the collection is immutable
+     *     and originals contains a string which starts with the specified
+     *     search string.
+     * @throws IllegalArgumentException if any parameter is null
+     * @throws IllegalArgumentException if originals contains a null element.
+     *     <b>Note: the collection may be modified before this is thrown</b>
+     */
+    @NotNull
+    @Contract(pure = true)
+    public <T extends Collection<String>> T copyMatches(
+        @NotNull final String token,
+        @NotNull final Iterable<String> originals,
+        @NotNull final T collection
+    ) {
+        return StringUtil.copyPartialMatches(token, originals, collection);
+    }
+}