Add an OptionHelper class with useful methods for working with options (

#31)

* Add an OptionHelper class with useful methods for working with options

* final class and private constructor

* Add more annotations and update method docs

* Add license header and missing annotation

* Fix comment for optBoolean

command/src/main/java/pw/chew/jdachewtils/command/OptionHelper.java

@@ -0,0 +1,202 @@
+/*
+ * Copyright 2016-2021 John Grosh (jagrosh) & Kaidan Gustave (TheMonitorLizard) & Olivia (Chew)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package pw.chew.jdachewtils.command;
+
+import net.dv8tion.jda.api.entities.GuildChannel;
+import net.dv8tion.jda.api.entities.IMentionable;
+import net.dv8tion.jda.api.entities.Member;
+import net.dv8tion.jda.api.entities.MessageChannel;
+import net.dv8tion.jda.api.entities.Role;
+import net.dv8tion.jda.api.entities.User;
+import net.dv8tion.jda.api.events.interaction.SlashCommandEvent;
+import net.dv8tion.jda.api.interactions.commands.OptionMapping;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * A collection of useful methods for working with Options.
+ */
+public final class OptionHelper {
+    private OptionHelper() {}
+
+    /**
+     * Guarantees a String option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static String optString(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable String defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsString();
+    }
+
+    /**
+     * Guarantees a boolean option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    public static boolean optBoolean(@NotNull SlashCommandEvent event, @NotNull String option, boolean defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsBoolean();
+    }
+
+    /**
+     * Guarantees a long option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    public static long optLong(@NotNull SlashCommandEvent event, @NotNull String option, long defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsLong();
+    }
+
+    /**
+     * Guarantees a double option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    public static double optDouble(@NotNull SlashCommandEvent event, @NotNull String option, double defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsDouble();
+    }
+
+    /**
+     * Guarantees a Guild Channel option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static GuildChannel optGuildChannel(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable GuildChannel defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsGuildChannel();
+    }
+
+    /**
+     * Guarantees a Member option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static Member optMember(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable Member defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsMember();
+    }
+
+    /**
+     * Guarantees a IMentionable option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static IMentionable optMentionable(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable IMentionable defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsMentionable();
+    }
+
+    /**
+     * Guarantees a Role option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static Role optRole(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable Role defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsRole();
+    }
+
+    /**
+     * Guarantees a User option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static User optUser(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable User defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsUser();
+    }
+
+    /**
+     * Guarantees a MessageChannel option value by providing a default value.
+     *
+     * @param event        The slash command event to get options from
+     * @param option       The option we want
+     * @param defaultValue The fallback option in case of the absence of the option value
+     * @return The provided option, or the default value if the option is not present
+     */
+    @Nullable
+    @Contract("_, _, !null -> !null")
+    public static MessageChannel optMessageChannel(@NotNull SlashCommandEvent event, @NotNull String option, @Nullable MessageChannel defaultValue) {
+        List<OptionMapping> options = event.getOptionsByName(option);
+
+        return options.isEmpty() ? defaultValue : options.get(0).getAsMessageChannel();
+    }
+
+    /**
+     * Checks to see if the event has an option.
+     *
+     * @param event  the slash command event to get options from
+     * @param option the option we want
+     * @return true if the option exists, false otherwise
+     */
+    public static boolean hasOption(@NotNull SlashCommandEvent event, @NotNull String option) {
+        return !event.getOptionsByName(option).isEmpty();
+    }
+}