Iterable<Character> result = Traverser.forGraph(graph).breadthFirst('a');

    assertEqualCharNodes(Iterables.limit(result, 2), "ab");
    assertThat(graph.requestedNodes).containsExactly('a', 'a', 'b');

    // Iterate again to see if calculation is done again
    assertEqualCharNodes(Iterables.limit(result, 2), "ab");
    assertThat(graph.requestedNodes).containsExactly('a', 'a', 'a', 'b', 'b');
  }

  @Test

    };
  }

  /**
   * Uses a hash table to map keys to value collections.
   *
   * <p>The collections returned by {@link Multimap#keySet()}, {@link Multimap#keys()}, and {@link
   * Multimap#asMap()} will iterate through the keys in the order that they were first added to the
   * multimap, save that if all values associated with a key are removed and then the key is added

```java
DataService ds = container.getComponent("dataService");

// Count
int count = ds.getCount(sessionId);

// Get by URL
AccessResult result = ds.getAccessResult(sessionId, url);

// Iterate all
ds.iterate(sessionId, accessResult -> {
    System.out.println(accessResult.getUrl());
    System.out.println(accessResult.getContent());
});

// Cleanup
ds.delete(sessionId);
```

    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();

    } catch (UnsupportedOperationException expected) {
    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();

    }

    /**
     * Iterates through all access results for a session, calling the callback for each result.
     * Uses OpenSearch scroll API for efficient iteration over large result sets.
     *
     * @param sessionId The session ID.
     * @param callback The callback to execute for each access result.
     */
    @Override

                assertTrue(urlQueue.getUrl().startsWith(url2));
            }

            dataService.iterate(sessionId1, accessResult -> {
                assertTrue(accessResult.getUrl().startsWith(url1));
                assertEquals(Constants.GET_METHOD, accessResult.getMethod());
            });
            dataService.iterate(sessionId2, accessResult -> {
                assertTrue(accessResult.getUrl().startsWith(url2));

```

## Data Access and Storage

### Accessing Crawled Data

```java
// Get data service
DataService dataService = container.getComponent("dataService");

// Iterate through crawled data
dataService.iterate(sessionId, accessResult -> {
    System.out.println("URL: " + accessResult.getUrl());
    System.out.println("Status: " + accessResult.getHttpStatusCode());

   */
  static DoubleStream megaPrimitiveDoubleStream() {
    return DoubleStream.iterate(0.0, x -> x + 1.0).limit(MEGA_STREAM_COUNT).parallel();
  }

  /** Returns a stream containing half the values from {@link #megaPrimitiveDoubleStream}. */
  static DoubleStream megaPrimitiveDoubleStreamPart1() {
    return DoubleStream.iterate(0.0, x -> x + 2.0).limit(MEGA_STREAM_COUNT / 2).parallel();
  }

  /**

            @Override
            public List<AccessResult<?>> getAccessResultList(String url, boolean hasData) {
                return null;
            }

            @Override
            public void iterate(String sessionId, AccessResultCallback<AccessResult<?>> callback) {
            }
        };

        CrawlingParameterUtil.setDataService(service);

        // Verify it can be retrieved