snuyanzin commented on code in PR #28688:
URL: https://github.com/apache/flink/pull/28688#discussion_r3658409889
##########
flink-table/flink-table-runtime/src/main/java/org/apache/flink/table/runtime/functions/SqlJsonUtils.java:
##########
@@ -374,6 +374,89 @@ private static Object errorResultForJsonQuery(
}
}
+ /** Accepts a pre-parsed context from {@link #jsonParse}. */
+ public static Integer jsonLength(final JsonValueContext parsedInput) {
+ // TODO FLINK-40233: A null context can result from a shared parse
that was short-circuited
+ // before parsing.
+ if (parsedInput == null || parsedInput.hasException()) {
+ return null;
+ }
+
+ // Whole document: a top-level JSON null literal counts as a scalar
(length 1).
+ return jsonLengthValue(parsedInput.obj);
+ }
+
+ /** Accepts a pre-parsed context from {@link #jsonParse}. */
+ public static Integer jsonLength(final JsonValueContext parsedInput, final
String pathSpec) {
+ // TODO FLINK-40233: A null context can result from a shared parse
that was short-circuited
+ // before parsing.
+ if (parsedInput == null || parsedInput.hasException()) {
+ return null;
+ }
+
+ final Matcher matcher = JSON_PATH_BASE.matcher(pathSpec);
+ final boolean isExplicitLaxStrict = matcher.matches();
+ if (isExplicitLaxStrict) {
+ throw new TableRuntimeException(
+ String.format(
+ "JSON_LENGTH does not support the 'lax'/'strict'
path mode prefix (got: '%s'). "
+ + "Use a plain path such as '$.a.b'. To
check path existence or handle "
+ + "invalid input, use JSON_EXISTS or IS
JSON.",
+ pathSpec));
+ }
+ final JsonPathContext context = jsonApiCommonSyntax(parsedInput,
pathSpec);
+ final Object value = context.obj;
+ if (value == null) {
+ if (pathExists(parsedInput.obj, pathSpec)) {
+ // literal null
+ return 1;
+ } else {
+ return null;
+ }
+ }
+
+ if (!JsonPath.isPathDefinite(pathSpec)) {
+ final List<?> matched = (List<?>) value;
+ return matched.size() == 1 ? jsonLengthValue(matched.get(0)) :
null;
+ }
+
+ return jsonLengthValue(value);
+ }
+
+ private static int jsonLengthValue(final Object value) {
+ if (value instanceof Map) {
+ return ((Map<?, ?>) value).size();
+ }
+ if (value instanceof List<?>) {
+ return ((List<?>) value).size();
+ }
+ // Scalars, including a JSON null literal, have length 1.
+ return 1;
+ }
+
+ /**
+ * Returns whether {@code pathSpec} matches at least one node in {@code
json}, independent of
+ * whether the matched value is a JSON null literal. Uses {@link
Option#AS_PATH_LIST} so the
+ * result is the list of matched canonical paths, which is empty iff the
path does not exist.
+ */
+ private static boolean pathExists(final Object json, final String
pathSpec) {
+ try {
+ final List<String> matched =
+ JsonPath.parse(
+ json,
+ Configuration.builder()
+ .options(
+ Option.AS_PATH_LIST,
Option.SUPPRESS_EXCEPTIONS)
Review Comment:
why are we parsing another time here?
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