feat(gax): add ResumableUploadCallable and ResumableUploadCallSettings

Clean up ResumableUploadCallSettingsTest JUnit 5 test suite by removing redundant equals/hashCode test for @autovalue. Add ResumableUploadCallable abstract base class.

Author: blakeli0

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ResumableUploadCallSettings.java

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.google.api.gax.rpc;
+
+import com.google.api.core.BetaApi;
+import com.google.auto.value.AutoValue;
+
+/**
+ * A settings class to configure a {@link ResumableUploadCallable} for executing resumable
+ * uploads. Encapsulates protocol options such as payload chunk size.
+ */
+@BetaApi
+@AutoValue
+public abstract class ResumableUploadCallSettings {
+  private static final int DEFAULT_CHUNK_SIZE = 8 * 1024 * 1024; // 8 MB
+
+  /** Returns the configured chunk size in bytes (defaults to 8 MB / 8,388,608 bytes). */
+  public abstract int getChunkSize();
+
+  /**
+   * Merges another {@code ResumableUploadCallSettings} instance with this one.
+   * Fields set in {@code other} override fields in this instance.
+   *
+   * @param other settings to overlay; may be {@code null}
+   * @return a new, resolved {@code ResumableUploadCallSettings} instance
+   */
+  public ResumableUploadCallSettings merge(ResumableUploadCallSettings other) {
+    if (other == null) {
+      return this;
+    }
+    return toBuilder().setChunkSize(other.getChunkSize()).build();
+  }
+
+  public abstract Builder toBuilder();
+
+  public static Builder newBuilder() {
+    return new AutoValue_ResumableUploadCallSettings.Builder()
+        .setChunkSize(DEFAULT_CHUNK_SIZE);
+  }
+
+  /** Builder for {@link ResumableUploadCallSettings}. */
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setChunkSize(int chunkSize);
+
+    public abstract int getChunkSize();
+
+    public abstract ResumableUploadCallSettings build();
+  }
+}

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ResumableUploadCallable.java

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+/*
+ * Copyright 2026 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.google.api.gax.rpc;
+
+import com.google.api.core.ApiFuture;
+import com.google.api.core.BetaApi;
+import java.io.InputStream;
+
+/**
+ * A ResumableUploadCallable is an API-transport-independent wrapper for the Resumable Upload
+ * protocol. Operates directly on the request object and input stream payload.
+ *
+ * @param <RequestT> request type
+ * @param <ResponseT> response type
+ */
+@BetaApi
+public abstract class ResumableUploadCallable<RequestT, ResponseT> {
+
+  protected ResumableUploadCallable() {}
+
+  /**
+   * Performs the resumable upload asynchronously with custom call settings.
+   *
+   * @param request the request message
+   * @param payload the data payload input stream
+   * @param settings call settings overrides; may be {@code null}
+   * @return future for the response
+   */
+  public abstract ApiFuture<ResponseT> futureCall(
+      RequestT request,
+      InputStream payload,
+      ResumableUploadCallSettings settings);
+}

sdk-platform-java/gax-java/gax/src/test/java/com/google/api/gax/rpc/ResumableUploadCallSettingsTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.google.api.gax.rpc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+import org.junit.jupiter.api.Test;
+
+public class ResumableUploadCallSettingsTest {
+
+  @Test
+  public void testDefaultChunkSizeInBuilder() {
+    ResumableUploadCallSettings settings = ResumableUploadCallSettings.newBuilder().build();
+
+    assertEquals(8 * 1024 * 1024, settings.getChunkSize());
+  }
+
+  @Test
+  public void testCustomInitialization() {
+    ResumableUploadCallSettings settings =
+        ResumableUploadCallSettings.newBuilder().setChunkSize(16 * 1024 * 1024).build();
+
+    assertEquals(16 * 1024 * 1024, settings.getChunkSize());
+  }
+
+  @Test
+  public void testMerge_NullSettings() {
+    ResumableUploadCallSettings stubSettings =
+        ResumableUploadCallSettings.newBuilder().setChunkSize(4 * 1024 * 1024).build();
+
+    ResumableUploadCallSettings merged = stubSettings.merge(null);
+
+    assertSame(stubSettings, merged);
+  }
+
+  @Test
+  public void testMerge_SettingsOverrides() {
+    ResumableUploadCallSettings stubSettings =
+        ResumableUploadCallSettings.newBuilder().setChunkSize(4 * 1024 * 1024).build();
+
+    ResumableUploadCallSettings perRequestSettings =
+        ResumableUploadCallSettings.newBuilder().setChunkSize(32 * 1024 * 1024).build();
+
+    ResumableUploadCallSettings merged = stubSettings.merge(perRequestSettings);
+
+    // Chunk size overridden by Tier-1 per-request settings
+    assertEquals(32 * 1024 * 1024, merged.getChunkSize());
+  }
+}