Add arrayGroup construct

extensions/json-jackson/src/test/java/io/deephaven/json/JsonStreamPublisherTest.java

@@ -20,6 +20,7 @@
 
 import java.io.Closeable;
 import java.io.File;
+import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
 import java.nio.ByteBuffer;
@@ -228,6 +229,48 @@ void singleObjectArray() {
         }
     }
 
+    // This is harder to implement than it looks like; right now, we expect chunks to be handed off at the same time and
+    // do it in a streaming fashion. But in the case where we have a very large grouped array, we'd need to buffer all
+    // of the first column.
+    //
+    // {
+    // "prices": [1.0, 2.0, ..., 1000000.0],
+    // "sizes": [1, 2, ..., 1000000]
+    // }
+    //
+    // whereas with the logical equivalent (from data perspective):
+    //
+    // [ { "price": 1.0, "size": 1 }, { "price": 2.0, "size": 2 }, ..., { "price": 1000000.0, "size": 1000000 } ]
+    //
+    // can process this in streaming fashion.
+    @Disabled("feature not implemented")
+    @Test
+    void singleObjectFieldArrayGroup() throws IOException {
+        final JsonStreamPublisher publisher = publisher(ObjectOptions.builder()
+                .addFields(ObjectFieldOptions.builder()
+                        .name("names")
+                        .options(StringOptions.standard().array())
+                        .arrayGroup("names_and_ages")
+                        .build())
+                .addFields(ObjectFieldOptions.builder()
+                        .name("ages")
+                        .options(IntOptions.standard().array())
+                        .arrayGroup("names_and_ages")
+                        .build())
+                .build(), false);
+        try (final StreamConsumerRecorder recorder = new StreamConsumerRecorder(publisher)) {
+            publisher.register(recorder);
+            // { "names": ["foo", null, "bar", "baz", null, null], "ages": [42, null, 43, null, 44, null] }
+            directExecute(publisher, Source.of(
+                    "{ \"names\": [\"foo\", null, \"bar\", \"baz\", null, null], \"ages\": [42, null, 43, null, 44, null] }"));
+            recorder.flushPublisher();
+            recorder.assertEquals(
+                    ObjectChunk.chunkWrap(new String[] {"foo", null, "bar", "baz", null, null}),
+                    IntChunk.chunkWrap(new int[] {42, NULL_INT, 43, NULL_INT, 44, NULL_INT}));
+            recorder.clear();
+        }
+    }
+
     @Test
     void singlePrimitiveKv() {
         final JsonStreamPublisher publisher =

extensions/json-jackson/src/test/java/io/deephaven/json/ObjectOptionsTest.java

@@ -134,6 +134,43 @@ void caseInsensitiveOverlap() {
         }
     }
 
+    @Test
+    void objectFields() throws IOException {
+        // { "prices": [1.1, 2.2, 3.3], "other": [2, 4, 8, 16] }
+        parse(ObjectOptions.builder()
+                .putFields("prices", DoubleOptions.standard().array())
+                .putFields("other", LongOptions.standard().array())
+                .build(),
+                "{ \"prices\": [1.1, 2.2, 3.3], \"other\": [2, 4, 8, 16] }",
+                ObjectChunk
+                        .chunkWrap(new Object[] {new double[] {1.1, 2.2, 3.3}}),
+                ObjectChunk.chunkWrap(new Object[] {
+                        new long[] {2, 4, 8, 16}}));
+    }
+
+    @Test
+    void objectFieldsArrayGroup() throws IOException {
+        // Note: array groups don't cause any difference wrt ObjectProcessor based destructuring
+        // { "prices": [1.1, 2.2, 3.3], "sizes": [2, 4, 8] }
+        parse(ObjectOptions.builder()
+                .addFields(ObjectFieldOptions.builder()
+                        .name("prices")
+                        .options(DoubleOptions.standard().array())
+                        .arrayGroup("prices_and_sizes")
+                        .build())
+                .addFields(ObjectFieldOptions.builder()
+                        .name("sizes")
+                        .options(LongOptions.standard().array())
+                        .arrayGroup("prices_and_sizes")
+                        .build())
+                .build(),
+                "{ \"prices\": [1.1, 2.2, 3.3], \"sizes\": [2, 4, 8] }",
+                ObjectChunk
+                        .chunkWrap(new Object[] {new double[] {1.1, 2.2, 3.3}}),
+                ObjectChunk.chunkWrap(new Object[] {
+                        new long[] {2, 4, 8}}));
+    }
+
     @Test
     void columnNames() {
         assertThat(OBJECT_NAME_AGE_FIELD.named(String.class).columnNames()).containsExactly("name", "age");

extensions/json/src/main/java/io/deephaven/json/ObjectFieldOptions.java

@@ -8,6 +8,7 @@
 import org.immutables.value.Value.Default;
 import org.immutables.value.Value.Immutable;
 
+import java.util.Optional;
 import java.util.Set;
 import java.util.TreeSet;
 
@@ -56,6 +57,20 @@ public RepeatedBehavior repeatedBehavior() {
         return RepeatedBehavior.USE_FIRST;
     }
 
+    /**
+     * The array group for {@code this} field. This is useful in scenarios where {@code this} field's array is
+     * guaranteed to have the same cardinality as one or more other array fields. For example, in the following snippet,
+     * we would model "prices" and "quantities" as having the same array group:
+     *
+     * <pre>
+     * {
+     *   "prices": [1.1, 2.2, 3.3],
+     *   "quantities": [9, 5, 42],
+     * }
+     * </pre>
+     */
+    public abstract Optional<Object> arrayGroup();
+
     public enum RepeatedBehavior {
         /**
          * Throws an error if a repeated field is encountered
@@ -88,6 +103,8 @@ public interface Builder {
 
         Builder caseInsensitiveMatch(boolean caseInsensitiveMatch);
 
+        Builder arrayGroup(Object arrayGroup);
+
         ObjectFieldOptions build();
     }
 
@@ -109,4 +126,14 @@ final void checkNonOverlapping() {
             }
         }
     }
+
+    @Check
+    final void checkArrayGroup() {
+        if (arrayGroup().isEmpty()) {
+            return;
+        }
+        if (!(options() instanceof ArrayOptions)) {
+            throw new IllegalArgumentException("arrayGroup is only valid with ArrayOptions");
+        }
+    }
 }