devmadhuu commented on code in PR #6969:
URL: https://github.com/apache/ozone/pull/6969#discussion_r1804756413
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hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/ReconUtils.java:
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@@ -596,6 +600,103 @@ public static long convertToEpochMillis(String
dateString, String dateFormat, Ti
}
}
+ public static boolean validateStartPrefix(String startPrefix) {
+
+ // Ensure startPrefix starts with '/' for non-empty values
+ startPrefix = startPrefix.startsWith("/") ? startPrefix : "/" +
startPrefix;
+
+ // Split the path to ensure it's at least at the bucket level
(volume/bucket).
+ String[] pathComponents = startPrefix.split("/");
+ if (pathComponents.length < 3 || pathComponents[2].isEmpty()) {
+ return false; // Invalid if not at bucket level or deeper
+ }
+
+ return true;
+ }
+
+ /**
+ * Retrieves keys from the specified table based on pagination and prefix
filtering.
+ * This method handles different scenarios based on the presence of {@code
startPrefix}
+ * and {@code prevKey}, enabling efficient key retrieval from the table.
+ *
+ * The method handles the following cases:
+ *
+ * 1. {@code prevKey} provided, {@code startPrefix} empty:
+ * - Seeks to {@code prevKey}, skips it, and returns subsequent records
up to the limit.
+ *
+ * 2. {@code prevKey} empty, {@code startPrefix} empty:
+ * - Iterates from the beginning of the table, retrieving all records up
to the limit.
+ *
+ * 3. {@code startPrefix} provided, {@code prevKey} empty:
+ * - Seeks to the first key matching {@code startPrefix} and returns all
matching keys up to the limit.
+ *
+ * 4. {@code startPrefix} provided, {@code prevKey} provided:
+ * - Seeks to {@code prevKey}, skips it, and returns subsequent keys that
match {@code startPrefix},
+ * up to the limit.
+ *
+ * This method also handles the following {@code limit} scenarios:
+ * - If {@code limit == 0} or {@code limit < -1}, no records are returned.
+ * - If {@code limit == -1}, all records are returned.
+ * - For positive {@code limit}, it retrieves records up to the specified
{@code limit}.
+ *
+ * @param table The table to retrieve keys from.
+ * @param startPrefix The search prefix to match keys against.
+ * @param limit The maximum number of keys to retrieve.
+ * @param prevKey The key to start after for the next set of records.
+ * @return A map of keys and their corresponding {@code OmKeyInfo} or {@code
RepeatedOmKeyInfo} objects.
+ * @throws IOException If there are problems accessing the table.
+ */
+ public static <T> Map<String, T> extractKeysFromTable(
+ Table<String, T> table, String startPrefix, int limit, String prevKey)
+ throws IOException {
+
+ Map<String, T> matchedKeys = new LinkedHashMap<>();
+
+ // If limit = 0, return an empty result set
+ if (limit == 0 || limit < -1) {
+ return matchedKeys;
+ }
+
+ // If limit = -1, set it to Integer.MAX_VALUE to return all records
+ int actualLimit = (limit == -1) ? Integer.MAX_VALUE : limit;
+
+ try (TableIterator<String, ? extends Table.KeyValue<String, T>> keyIter =
table.iterator()) {
Review Comment:
Need to do null check for table, as we have faced issues in past when
`omMetaManager` is still initalizing and may throw NPE here on `table` object
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