+ /**
+ * Cast well know java types based on {@link Object#toString()} of the provided
+ * object.
+ *
+ */
+ @SuppressWarnings("unchecked")
+ public static <T> Optional<T> cast(Class<T> clss, Object value) {
+ // TODO Or should we?
+ Objects.requireNonNull(value, "Cannot cast a null value");
+ if (String.class.isAssignableFrom(clss)) {
+ return Optional.of((T) value.toString());
+ }
+ // Numbers
+ else if (Long.class.isAssignableFrom(clss)) {
+ if (value instanceof Long)
+ return Optional.of((T) value);
+ return Optional.of((T) Long.valueOf(value.toString()));
+ } else if (Integer.class.isAssignableFrom(clss)) {
+ if (value instanceof Integer)
+ return Optional.of((T) value);
+ return Optional.of((T) Integer.valueOf(value.toString()));
+ } else if (Double.class.isAssignableFrom(clss)) {
+ if (value instanceof Double)
+ return Optional.of((T) value);
+ return Optional.of((T) Double.valueOf(value.toString()));
+ }
+ // Numbers
+// else if (Number.class.isAssignableFrom(clss)) {
+// if (value instanceof Number)
+// return Optional.of((T) value);
+// return Optional.of((T) Number.valueOf(value.toString()));
+// }
+ return Optional.empty();
+ }
+
+ /** Utility to convert a data: URI to bytes. */
+ public static byte[] bytesFromDataURI(URI uri) {
+ if (!"data".equals(uri.getScheme()))
+ throw new IllegalArgumentException("URI must have 'data' as a scheme");
+ String schemeSpecificPart = uri.getSchemeSpecificPart();
+ int commaIndex = schemeSpecificPart.indexOf(',');
+ String prefix = schemeSpecificPart.substring(0, commaIndex);
+ List<String> info = Arrays.asList(prefix.split(";"));
+ if (!info.contains("base64"))
+ throw new IllegalArgumentException("URI must specify base64");
+
+ String base64Str = schemeSpecificPart.substring(commaIndex + 1);
+ return Base64.getDecoder().decode(base64Str);
+
+ }
+
+ /** Utility to convert bytes to a data: URI. */
+ public static URI bytesToDataURI(byte[] arr) {
+ String base64Str = Base64.getEncoder().encodeToString(arr);
+ try {
+ final String PREFIX = "data:application/octet-stream;base64,";
+ return new URI(PREFIX + base64Str);
+ } catch (URISyntaxException e) {
+ throw new IllegalStateException("Cannot serialize bytes a Base64 data URI", e);
+ }
+
+ }
+