Fix checkstyle

Author: Defective4

src/main/java/net/discordjug/javabot/systems/staff_commands/forms/model/FormData.java

@@ -12,6 +12,26 @@
 
 /**
  * Class containing information about a form.
+ * 
+ * @param id             the form ID.
+ * @param fields         a list of text input fields associated with this form.
+ *                       A form can only hold a maximum of 5 fields at a time.
+ * @param title          form title used in the modal displayed to the user.
+ * @param submitChannel  ID of the channel the form submissions are sent to.
+ * @param submitMessage  message displayed to the user once they submit the
+ *                       form.
+ * @param messageId      ID of the message this form is attached to. null if the
+ *                       form is not attached to any message.
+ * @param messageChannel channel of the message this form is attached to. null
+ *                       if the form is not attached to any message.
+ * @param expiration     time after which this user won't accept any further
+ *                       submissions. null to indicate that the form has no
+ *                       expiration date.
+ * @param closed         closed state of this form. If the form is closed, it
+ *                       doesn't accept further submissions, even if it's
+ *                       expired.
+ * @param onetime        onetime state of this form. If it's true, the form only
+ *                       accepts one submission per user.
  */
 // TODO `Optional` getter for the submit message
 public record FormData(long id, List<FormField> fields, String title, long submitChannel, String submitMessage,
@@ -23,9 +43,15 @@ public record FormData(long id, List<FormField> fields, String title, long submi
 	 */
 	public static final long EXPIRATION_PERMANENT = -1;
 
+	/**
+	 * The main constructor.
+	 */
 	public FormData {
 		Objects.requireNonNull(title);
 		fields = List.copyOf(fields);
+		if (fields.size() > 5) {
+			throw new IllegalArgumentException("fields.size() > 5");
+		}
 	}
 
 	public boolean isAttached() {

src/main/java/net/discordjug/javabot/systems/staff_commands/forms/model/FormField.java

@@ -1,15 +1,45 @@
 package net.discordjug.javabot.systems.staff_commands.forms.model;
 
+import java.util.Objects;
+
 import net.dv8tion.jda.api.interactions.components.text.TextInput;
 import net.dv8tion.jda.api.interactions.components.text.TextInputStyle;
 
 /**
- * Represents a form field.
- * Form fields are used to store data about text inputs presented to the user in the form modal.
- * Each form can have up to 5 fields.
+ * Represents a form field. Form fields are used to store data about text inputs
+ * presented to the user in the form modal. Each form can have up to 5 fields.
+ * 
+ * @param label       field label.
+ * @param max         maximum number of characters allowed to be entered in this
+ *                    field.
+ * @param min         minimum number of characters required. Setting min to a
+ *                    value greater than 0 will make this field effectively
+ *                    required, even if the {@code required} parameter is set to
+ *                    false.
+ * @param placeholder field placeholder. Use null to use any placeholder.
+ * @param required    whether or not the user has to type something in this
+ *                    field.
+ * @param style       text input style.
+ * @param value       initial field value. Can be null to indicate no inital
+ *                    value.
+ * @param id          form id.
  */
-public record FormField(String label, int max, int min, String placeholder, boolean required,
-		TextInputStyle style, String value, long id) {
+public record FormField(String label, int max, int min, String placeholder, boolean required, TextInputStyle style,
+		String value, long id) {
+
+	/**
+	 * The main constructor.
+	 */
+	public FormField {
+		Objects.requireNonNull(label);
+		if (min < 0) throw new IllegalArgumentException("min < 0");
+
+		if (max < 1) throw new IllegalArgumentException("max < 1");
+
+		if (max < min) throw new IllegalArgumentException("max < min");
+
+		Objects.requireNonNull(style);
+	}
 
 	/**
 	 * Create a text input from this field.

src/main/java/net/discordjug/javabot/systems/staff_commands/forms/model/FormUser.java

@@ -2,6 +2,9 @@
 
 /**
  * Represents a user who submitted a form.
+ * 
+ * @param id       user's ID.
+ * @param username user's Discord username.
  */
 public record FormUser(long id, String username) {