OZG-6891 KOP-2735 xta-file: Add javadoc

src/main/java/de/ozgcloud/xta/client/model/XtaFile.java

@@ -10,6 +10,31 @@ import jakarta.validation.constraints.PositiveOrZero;
 
 import lombok.Builder;
 
+/**
+ * Represents a file in the XTA context.
+ *
+ * <p>
+ * <small>Parameter documentation strings translated from <i>XTA-Webservice-Datentypen.xsd</i>.</small>
+ * </p>
+ *
+ * @param content            A data handler of the file content. <p>This field is required.</p>
+ * @param contentType        This attribute specifies the MIME type of the contained content, so it includes entries like {@code text/xml},
+ *                           {@code text/plain}, {@code application/gzip}, or {@code application/pdf}. <p>This field is required as it is particularly
+ *                           important information (handled analogously in email).</p>
+ * @param contentDescription The description of the content, e.g., 'Offer' or 'Invoice'. <p>This field is optional.</p>
+ * @param encoding           The character set that was used for encoding the content. <p>This field is optional.</p>
+ * @param name               The filename of the data source, if the content was taken from a file. E.g.: For the transmission of xdomea messages,
+ *                           this attribute is mandatory. <p>This field is recommended as it is required for xdomea.</p>
+ * @param id                 Provides the ability to reference the content via, for example, a running number. <p>This field is optional and will be
+ *                           automatically set by the XTA server.</p>
+ * @param language           Language of the file content, for instance, {@code en-US} or {@code de-DE}, see <a
+ *                           href="http://www.ietf.org/rfc/rfc3066.txt">RFC 3066</a>. <p>This field is optional.</p>
+ * @param size               The size of the file content in bytes.
+ *
+ *                           <p>
+ *                           This field is optional and will be automatically set by the XTA server.
+ *                           </p>
+ */
 @Builder(toBuilder = true)
 public record XtaFile(
 		@NotNull DataHandler content,
@@ -19,6 +44,6 @@ public record XtaFile(
 		@NotBlank String name,
 		@Nullable String id,
 		@Nullable String language,
-		@PositiveOrZero BigInteger size
+		@Nullable @PositiveOrZero BigInteger size
 ) {
 }