resume cursor

Author: rashtao

core/src/main/java/com/arangodb/ArangoDatabase.java

@@ -310,6 +310,20 @@ public interface ArangoDatabase extends ArangoSerdeAccessor {
      */
     <T> ArangoCursor<T> cursor(String cursorId, Class<T> type);
 
+    /**
+     * Return an cursor from the given cursor-ID if still existing
+     *
+     * @param cursorId    The ID of the cursor
+     * @param type        The type of the result (POJO or {@link com.arangodb.util.RawData})
+     * @param nextBatchId The ID of the next cursor batch (set only if cursor allows retries, see
+     *                    {@link AqlQueryOptions#allowRetry(Boolean)}
+     * @return cursor of the results
+     * @see <a href= "https://www.arangodb.com/docs/stable/http/aql-query-cursor-accessing-cursors
+     * .html#read-next-batch-from-cursor">API Documentation</a>
+     * @since ArangoDB 3.11
+     */
+    <T> ArangoCursor<T> cursor(String cursorId, Class<T> type, String nextBatchId);
+
     /**
      * Explain an AQL query and return information about it
      *

core/src/main/java/com/arangodb/internal/ArangoDatabaseImpl.java

@@ -183,8 +183,20 @@ public <T> ArangoCursor<T> query(final String query, final Class<T> type) {
     @Override
     public <T> ArangoCursor<T> cursor(final String cursorId, final Class<T> type) {
         final HostHandle hostHandle = new HostHandle();
-        final InternalCursorEntity result = executor
-                .execute(queryNextRequest(cursorId, null), internalCursorEntityDeserializer(), hostHandle);
+        final InternalCursorEntity result = executor.execute(
+                queryNextRequest(cursorId, null),
+                internalCursorEntityDeserializer(),
+                hostHandle);
+        return createCursor(result, type, null, hostHandle);
+    }
+
+    @Override
+    public <T> ArangoCursor<T> cursor(final String cursorId, final Class<T> type, final String nextBatchId) {
+        final HostHandle hostHandle = new HostHandle();
+        final InternalCursorEntity result = executor.execute(
+                queryNextByBatchIdRequest(cursorId, nextBatchId, null),
+                internalCursorEntityDeserializer(),
+                hostHandle);
         return createCursor(result, type, null, hostHandle);
     }
 

driver/src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -834,25 +834,33 @@ void queryWithMaxWarningCount(ArangoDatabase db) {
     @ParameterizedTest(name = "{index}")
     @MethodSource("dbs")
     void queryCursor(ArangoDatabase db) {
-        final int numbDocs = 10;
-        for (int i = 0; i < numbDocs; i++) {
-            db.collection(CNAME1).insertDocument(new BaseDocument(), null);
-        }
-
-        final int batchSize = 5;
-        final ArangoCursor<String> cursor = db.query("for i in " + CNAME1 + " return i._id", String.class,
-                new AqlQueryOptions().batchSize(batchSize).count(true));
-        assertThat((Object) cursor).isNotNull();
-        assertThat(cursor.getCount()).isGreaterThanOrEqualTo(numbDocs);
-
-        final ArangoCursor<String> cursor2 = db.cursor(cursor.getId(), String.class);
-        assertThat((Object) cursor2).isNotNull();
-        assertThat(cursor2.getCount()).isGreaterThanOrEqualTo(numbDocs);
-        assertThat((Iterator<?>) cursor2).hasNext();
+        ArangoCursor<Integer> cursor = db.query("for i in 1..4 return i", Integer.class,
+                new AqlQueryOptions().batchSize(1));
+        List<Integer> result = new ArrayList<>();
+        result.add(cursor.next());
+        result.add(cursor.next());
+        ArangoCursor<Integer> cursor2 = db.cursor(cursor.getId(), Integer.class);
+        result.add(cursor2.next());
+        result.add(cursor2.next());
+        assertThat(cursor2.hasNext()).isFalse();
+        assertThat(result).containsExactly(1, 2, 3, 4);
+    }
 
-        for (int i = 0; i < batchSize; i++, cursor.next()) {
-            assertThat((Iterator<?>) cursor).hasNext();
-        }
+    @ParameterizedTest(name = "{index}")
+    @MethodSource("dbs")
+    void queryCursorRetry(ArangoDatabase db) throws IOException {
+        assumeTrue(isAtLeastVersion(3, 11));
+        ArangoCursor<Integer> cursor = db.query("for i in 1..4 return i", Integer.class,
+                new AqlQueryOptions().batchSize(1).allowRetry(true));
+        List<Integer> result = new ArrayList<>();
+        result.add(cursor.next());
+        result.add(cursor.next());
+        ArangoCursor<Integer> cursor2 = db.cursor(cursor.getId(), Integer.class, cursor.getNextBatchId());
+        result.add(cursor2.next());
+        result.add(cursor2.next());
+        cursor2.close();
+        assertThat(cursor2.hasNext()).isFalse();
+        assertThat(result).containsExactly(1, 2, 3, 4);
     }
 
     @ParameterizedTest(name = "{index}")