Add helper method for synchronous use of feed client

3 files changed, 99 insertions, 0 deletions

diff --git a/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/FeedClient.java b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/FeedClient.java
index d463c611d6a..5e95990a078 100644
--- a/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/FeedClient.java
+++ b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/FeedClient.java
@@ -2,6 +2,7 @@
 package ai.vespa.feed.client;
 
 import java.io.Closeable;
+import java.util.List;
 import java.util.concurrent.CompletableFuture;
 
 /**
@@ -37,6 +38,24 @@ public interface FeedClient extends Closeable {
      */
     CompletableFuture<Result> remove(DocumentId documentId, OperationParameters params);
 
+    /**
+     * Waits for all feed operations to complete, either successfully or with exception.
+     * @throws MultiFeedException if any operation fails
+     * @return list of results with the same ordering as the {@code promises} parameter
+     * */
+    static List<Result> await(List<CompletableFuture<Result>> promises) throws MultiFeedException {
+        return Helper.await(promises);
+    }
+
+    /**
+     * Same as {@link #await(List)} except {@code promises} parameter is a vararg
+     * @see #await(List)
+     */
+    @SafeVarargs
+    static List<Result> await(CompletableFuture<Result>... promises) throws MultiFeedException {
+        return Helper.await(promises);
+    }
+
     /** Returns a snapshot of the stats for this feed client, such as requests made, and responses by status. */
     OperationStats stats();
 
diff --git a/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/Helper.java b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/Helper.java
new file mode 100644
index 00000000000..59c12077bef
--- /dev/null
+++ b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/Helper.java
@@ -0,0 +1,42 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package ai.vespa.feed.client;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.stream.Collectors;
+
+/**
+ * @author bjorncs
+ */
+class Helper {
+
+    private Helper() {}
+
+    @SafeVarargs
+    static List<Result> await(CompletableFuture<Result>... promises) throws MultiFeedException {
+        List<CompletableFuture<Result>> list = new ArrayList<>();
+        for (CompletableFuture<Result> p : promises) list.add(p);
+        return await(list);
+    }
+
+    static List<Result> await(List<CompletableFuture<Result>> promises) throws MultiFeedException {
+        try {
+            CompletableFuture.allOf(promises.toArray(new CompletableFuture<?>[0])).join();
+            return promises.stream()
+                    .map(p -> Objects.requireNonNull(p.getNow(null)))
+                    .collect(Collectors.toList());
+        } catch (CompletionException e) {
+            List<FeedException> exceptions = new ArrayList<>();
+            for (CompletableFuture<Result> promise : promises) {
+                if (promise.isCompletedExceptionally()) {
+                    // Lambda is executed on this thread since the future is already completed
+                    promise.whenComplete((__, error) -> exceptions.add((FeedException) error));
+                }
+            }
+            throw new MultiFeedException(exceptions);
+        }
+    }
+}
diff --git a/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/MultiFeedException.java b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/MultiFeedException.java
new file mode 100644
index 00000000000..5db687b49ff
--- /dev/null
+++ b/vespa-feed-client-api/src/main/java/ai/vespa/feed/client/MultiFeedException.java
@@ -0,0 +1,38 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package ai.vespa.feed.client;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * Aggregates multiple instances of {@link FeedException}
+ *
+ * @author bjorncs
+ */
+public class MultiFeedException extends RuntimeException {
+
+    private final List<FeedException> exceptions;
+
+    public MultiFeedException(Collection<FeedException> exceptions) {
+        super(toMessage(exceptions));
+        this.exceptions = Collections.unmodifiableList(new ArrayList<>(exceptions));
+    }
+
+    public Collection<FeedException> feedExceptions() { return exceptions; }
+
+    public Set<DocumentId> documentIds() {
+        return exceptions.stream()
+                .filter(e -> e.documentId().isPresent())
+                .map(e -> e.documentId().get())
+                .collect(Collectors.toSet());
+    }
+
+    private static String toMessage(Collection<FeedException> exceptions) {
+        return String.format("%d feed operations failed", exceptions.size());
+    }
+
+}