}

        @Test
        @DisplayName("Should combine referral data")
        void testCombine() {
            DfsReferralDataInternal combined = mock(DfsReferralDataInternal.class);

            // Test with mock
            when(mockReferralData.combine(mockDfsReferralData)).thenReturn(combined);
            DfsReferralDataInternal result = mockReferralData.combine(mockDfsReferralData);
            assertSame(combined, result);

 *
 * <p>The merger supports two main types of combinations:</p>
 * <ul>
 *   <li>Children combination: Controls how child elements are combined</li>
 *   <li>Self combination: Controls how the element itself is combined</li>
 * </ul>
 *
 * <p>Children combination modes (specified by {@code combine.children} attribute):</p>
 * <ul>
 *   <li>{@code merge} (default): Merges elements with matching names</li>

            second.setDomain("DOMAIN");

            // Combine
            DfsReferralDataInternal combined = first.combine(second);

            assertNotNull(combined);
            assertEquals("server2", combined.getServer());
            assertEquals("share2", combined.getShare());
            assertEquals("path2", combined.getPath());
            assertEquals("DOMAIN", combined.getDomain());

        Callable<C> combiner, Executor executor) {
      return new CombinedFuture<>(futures, allMustSucceed, executor, combiner);
    }

    /**
     * Creates the {@link ListenableFuture} which will return the result of running {@code combiner}
     * when all Futures complete. {@code combiner} will run using {@code executor}.
     *

import com.google.common.util.concurrent.ClosingFuture.Combiner;
import com.google.common.util.concurrent.ClosingFuture.Combiner.AsyncCombiningCallable;
import com.google.common.util.concurrent.ClosingFuture.Combiner.CombiningCallable;
import com.google.common.util.concurrent.ClosingFuture.Combiner2.AsyncClosingFunction2;
import com.google.common.util.concurrent.ClosingFuture.Combiner2.ClosingFunction2;

		},
		cli.BoolFlag{
			Usage: "combine inline data",
			Name:  "combine",
		},
		cli.BoolFlag{
			Usage: "combine inline data across versions when size matches",
			Name:  "xver",
		},
	}

	app.Action = func(c *cli.Context) error {
		ndjson := c.Bool("ndjson")
		if c.Bool("data") && c.Bool("combine") {
			return errors.New("cannot combine --data and --combine")
		}
		// file / version / file

import com.google.common.util.concurrent.ClosingFuture.Combiner;
import com.google.common.util.concurrent.ClosingFuture.Combiner.AsyncCombiningCallable;
import com.google.common.util.concurrent.ClosingFuture.Combiner.CombiningCallable;
import com.google.common.util.concurrent.ClosingFuture.Combiner2.AsyncClosingFunction2;
import com.google.common.util.concurrent.ClosingFuture.Combiner2.ClosingFunction2;

    /**
     * Reduces a map of boolean flag properties to a single provider by applying the given
     * combiner function to the corresponding values of the properties that are true.
     *
     * @param flags The map of boolean properties mapped to their values.
     * @param combiner The function to combine the values of the true properties.
     *
     * @return A provider of the reduced value. Non-present if no properties are true.

It will all be combined and included in your OpenAPI, and shown in the API docs:

<img src="/img/tutorial/additional-responses/image01.png">

## Combine predefined responses and custom ones { #combine-predefined-responses-and-custom-ones }

You might want to have some predefined responses that apply to many *path operations*, but you want to combine them with custom responses needed by each *path operation*.

     * Anyway, the purpose of this method is to implement a BinaryOperator combiner for a Collector,
     * so its return value will get used naturally.
     */
    @SuppressWarnings("CanIgnoreReturnValueSuggester")
    ImmutableTableCollectorState<R, C, V> combine(
        ImmutableTableCollectorState<R, C, V> other, BinaryOperator<V> merger) {