feat: add new dedupe utility method to Option classes

google-cloud-storage/src/main/java/com/google/cloud/storage/Blob.java

@@ -40,6 +40,7 @@
 import java.security.Key;
 import java.time.OffsetDateTime;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -163,6 +164,40 @@ public static BlobSourceOption shouldReturnRawInputStream(boolean shouldReturnRa
       return new BlobSourceOption(UnifiedOpts.returnRawInputStream(shouldReturnRawInputStream));
     }
 
+    /**
+     * Deduplicate any options which are the same parameter. The value which comes last in {@code
+     * os} will be the value included in the return.
+     */
+    @BetaApi
+    public static BlobSourceOption[] dedupe(BlobSourceOption... os) {
+      return Option.dedupe(BlobSourceOption[]::new, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobSourceOption[] dedupe(
+        Collection<BlobSourceOption> collection, BlobSourceOption... os) {
+      return Option.dedupe(BlobSourceOption[]::new, collection, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobSourceOption[] dedupe(BlobSourceOption[] array, BlobSourceOption... os) {
+      return Option.dedupe(BlobSourceOption[]::new, array, os);
+    }
+
     static Storage.BlobSourceOption[] toSourceOptions(
         BlobInfo blobInfo, BlobSourceOption... options) {
       Storage.BlobSourceOption[] convertedOptions = new Storage.BlobSourceOption[options.length];

google-cloud-storage/src/main/java/com/google/cloud/storage/Bucket.java

@@ -30,7 +30,6 @@
 import com.google.cloud.storage.UnifiedOpts.BucketSourceOpt;
 import com.google.cloud.storage.UnifiedOpts.ObjectOptExtractor;
 import com.google.cloud.storage.UnifiedOpts.ObjectTargetOpt;
-import com.google.cloud.storage.UnifiedOpts.OptionShim;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
 import java.io.IOException;
@@ -41,6 +40,7 @@
 import java.time.Duration;
 import java.time.OffsetDateTime;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -99,6 +99,41 @@ public static BucketSourceOption userProject(@NonNull String userProject) {
       return new BucketSourceOption(UnifiedOpts.userProject(userProject));
     }
 
+    /**
+     * Deduplicate any options which are the same parameter. The value which comes last in {@code
+     * os} will be the value included in the return.
+     */
+    @BetaApi
+    public static BucketSourceOption[] dedupe(BucketSourceOption... os) {
+      return Option.dedupe(BucketSourceOption[]::new, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BucketSourceOption[] dedupe(
+        Collection<BucketSourceOption> collection, BucketSourceOption... os) {
+      return Option.dedupe(BucketSourceOption[]::new, collection, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BucketSourceOption[] dedupe(
+        BucketSourceOption[] array, BucketSourceOption... os) {
+      return Option.dedupe(BucketSourceOption[]::new, array, os);
+    }
+
     static Storage.BucketSourceOption[] toSourceOptions(
         BucketInfo bucketInfo, BucketSourceOption... options) {
       Storage.BucketSourceOption[] convertedOptions =
@@ -237,6 +272,40 @@ public static BlobTargetOption userProject(@NonNull String userProject) {
       return new BlobTargetOption(UnifiedOpts.userProject(userProject));
     }
 
+    /**
+     * Deduplicate any options which are the same parameter. The value which comes last in {@code
+     * os} will be the value included in the return.
+     */
+    @BetaApi
+    public static BlobTargetOption[] dedupe(BlobTargetOption... os) {
+      return Option.dedupe(BlobTargetOption[]::new, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobTargetOption[] dedupe(
+        Collection<BlobTargetOption> collection, BlobTargetOption... os) {
+      return Option.dedupe(BlobTargetOption[]::new, collection, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobTargetOption[] dedupe(BlobTargetOption[] array, BlobTargetOption... os) {
+      return Option.dedupe(BlobTargetOption[]::new, array, os);
+    }
+
     static Storage.BlobTargetOption[] toTargetOptions(
         BlobInfo blobInfo, BlobTargetOption... options) {
       Storage.BlobTargetOption[] targetOptions = new Storage.BlobTargetOption[options.length];
@@ -255,7 +324,7 @@ static Storage.BlobTargetOption[] toTargetOptions(
   }
 
   /** Class for specifying blob write options when {@code Bucket} methods are used. */
-  public static class BlobWriteOption extends OptionShim<ObjectTargetOpt> implements Serializable {
+  public static class BlobWriteOption extends Option<ObjectTargetOpt> implements Serializable {
 
     private static final long serialVersionUID = 59762268190041584L;
 
@@ -366,6 +435,40 @@ public static BlobWriteOption userProject(@NonNull String userProject) {
       return new BlobWriteOption(UnifiedOpts.userProject(userProject));
     }
 
+    /**
+     * Deduplicate any options which are the same parameter. The value which comes last in {@code
+     * os} will be the value included in the return.
+     */
+    @BetaApi
+    public static BlobWriteOption[] dedupe(BlobWriteOption... os) {
+      return Option.dedupe(BlobWriteOption[]::new, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobWriteOption[] dedupe(
+        Collection<BlobWriteOption> collection, BlobWriteOption... os) {
+      return Option.dedupe(BlobWriteOption[]::new, collection, os);
+    }
+
+    /**
+     * Deduplicate any options which are the same parameter.
+     *
+     * <p>The value which comes last in {@code collection} and {@code os} will be the value included
+     * in the return. All options from {@code os} will override their counterparts in {@code
+     * collection}.
+     */
+    @BetaApi
+    public static BlobWriteOption[] dedupe(BlobWriteOption[] array, BlobWriteOption... os) {
+      return Option.dedupe(BlobWriteOption[]::new, array, os);
+    }
+
     static Storage.BlobWriteOption[] toWriteOptions(BlobInfo blobInfo, BlobWriteOption... options) {
       Storage.BlobWriteOption[] convertedOptions = new Storage.BlobWriteOption[options.length];
       for (int i = 0; i < options.length; i++) {

google-cloud-storage/src/main/java/com/google/cloud/storage/Option.java

@@ -18,6 +18,11 @@
 
 import com.google.cloud.storage.UnifiedOpts.Opt;
 import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.function.IntFunction;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /** Base class for Storage operation option. */
 @Deprecated
@@ -29,4 +34,32 @@ public abstract class Option<O extends Opt> extends UnifiedOpts.OptionShim<O>
   Option(O opt) {
     super(opt);
   }
+
+  @SafeVarargs
+  static <O extends Option<?>> O[] dedupe(IntFunction<O[]> gen, O... os) {
+    return dedupe(gen, Arrays.stream(os));
+  }
+
+  @SafeVarargs
+  static <O extends Option<?>> O[] dedupe(IntFunction<O[]> gen, Collection<O> collection, O... os) {
+    return dedupe(gen, Stream.of(collection.stream(), Arrays.stream(os)).flatMap(s -> s));
+  }
+
+  @SafeVarargs
+  static <O extends Option<?>> O[] dedupe(IntFunction<O[]> gen, O[] array, O... os) {
+    return dedupe(gen, Stream.of(Arrays.stream(array), Arrays.stream(os)).flatMap(s -> s));
+  }
+
+  /**
+   * All Options contain an {@link Opt}, {@code Opt}s are distinct classes allowing us to group
+   * based on those classes. Once grouped, we select the last element to provide last wins behavior.
+   *
+   * <p>Each of these helpers is an internal implementation detail, primarily due to the fact that
+   * generic arrays can not be instantiated in Java and requires a factory to be passed in.
+   */
+  private static <O extends Option<?>> O[] dedupe(IntFunction<O[]> gen, Stream<O> s) {
+    return s.collect(Collectors.groupingBy(o -> o.getOpt().getClass())).values().stream()
+        .map(l -> l.get(l.size() - 1))
+        .toArray(gen);
+  }
 }