public void scanIterator()

in hugegraph-store/hg-store-test/src/main/java/org/apache/hugegraph/store/HgSessionManagerRaftFakePDTest.java [491:596]
98 lines of code
16 McCabe index (conditional complexity)

    public void scanIterator() {
        HgStoreTestUtil.println("--- test scanIterator ---");
        String tableName = "UNIT_SCAN";
        String keyName = "SCAN-ITER";
        HgStoreSession session = getStoreSession();
        HgStoreTestUtil.batchPut(session, tableName, keyName, 10000);
        int count = 0;
        int limit = 0;
        int max = 99999;
        HgKvIterator<HgKvEntry> iterator = null;

        HgStoreTestUtil.println("-- test 0 element --");
        iterator = session.scanIterator(tableName, HgStoreTestUtil.toAllPartitionKey("__SCAN-001"),
                                        HgStoreTestUtil.toAllPartitionKey("__SCAN-100"), 0);
        Assert.assertFalse(iterator.hasNext());
        try {
            iterator.next();
            Assert.fail();
        } catch (Throwable t) {
            HgStoreTestUtil.println("-- test NoSuchElementException --");
            Assert.assertTrue(t instanceof NoSuchElementException);
        }

        HgStoreTestUtil.println("-- test limit 1 to 10 --");
        for (int i = 1; i <= 10; i++) {
            HgStoreTestUtil.println("- limit " + i + " -");
            limit = i;
            iterator = session.scanIterator(tableName,
                                            HgStoreTestUtil.toAllPartitionKey(keyName + "-0"),
                                            HgStoreTestUtil.toAllPartitionKey(keyName + "-1"),
                                            limit);
            count = 0;
            while (iterator.hasNext()) {
                count++;
                HgKvEntry entry = iterator.next();
                HgStoreTestUtil.println(entry);
            }
            Assert.assertEquals(limit, count);
        }

        HgStoreTestUtil.println("-- test limit 1 to 10 not enough --");
        for (int i = 1; i <= 10; i++) {
            HgStoreTestUtil.println("- limit " + i + " -");
            limit = i;
            iterator = session.scanIterator(tableName,
                                            HgStoreTestUtil.toAllPartitionKey(keyName + "-00001"),
                                            HgStoreTestUtil.toAllPartitionKey(keyName + "-00005"),
                                            limit);
            count = 0;
            while (iterator.hasNext()) {
                count++;
                HgKvEntry entry = iterator.next();
                HgStoreTestUtil.println(entry);
            }
            if (i <= 5) {
                Assert.assertEquals(limit, count);
            } else {
                Assert.assertEquals(5, count);
            }

        }

        HgStoreTestUtil.println("-- test limit 0 (no limit) --");
        limit = 0;
        iterator =
                session.scanIterator(tableName, HgStoreTestUtil.toAllPartitionKey(keyName + "-0"),
                                     HgStoreTestUtil.toAllPartitionKey(keyName + "-1"), limit);

        count = 0;
        while (iterator.hasNext()) {
            count++;
            HgKvEntry entry = iterator.next();
            if (count % 1000 == 0) {
                HgStoreTestUtil.println(entry);
            }
            if (count >= max) break;
        }
        Assert.assertEquals(10000, count);

        HgStoreTestUtil.println("-- test scan all --");
        iterator = session.scanIterator(tableName);
        count = 0;
        while (iterator.hasNext()) {
            count++;
            HgKvEntry entry = iterator.next();
            if (count % 1000 == 0) {
                HgStoreTestUtil.println(entry);
            }
            if (count >= max) break;
        }
        Assert.assertEquals(10000, count);

        HgStoreTestUtil.println("-- test scan prefix --");
        iterator =
                session.scanIterator(tableName, HgStoreTestUtil.toAllPartitionKey(keyName + "-01"));
        count = 0;
        while (iterator.hasNext()) {
            count++;
            HgKvEntry entry = iterator.next();
            if (count % 100 == 0) {
                HgStoreTestUtil.println(entry);
            }
            if (count >= max) break;
        }
        Assert.assertEquals(1000, count);
    }