[common] Support VECTOR elements in InternalArray accessors (#9773)

Author: LuciferYang

paimon-common/src/main/java/org/apache/paimon/data/BinaryArray.java

@@ -83,6 +83,7 @@ public static int calculateFixLengthPartSize(DataType type) {
             case TIMESTAMP_WITHOUT_TIME_ZONE:
             case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
             case ARRAY:
+            case VECTOR:
             case MULTISET:
             case MAP:
             case ROW:
@@ -260,7 +261,8 @@ public InternalArray getArray(int pos) {
 
     @Override
     public InternalVector getVector(int pos) {
-        throw new IllegalArgumentException("Unsupported type: VectorType");
+        assertIndexIsValid(pos);
+        return MemorySegmentUtils.readVectorData(segments, offset, getLong(pos));
     }
 
     @Override

paimon-common/src/main/java/org/apache/paimon/data/InternalArray.java

@@ -124,6 +124,9 @@ static ElementGetter createElementGetter(DataType elementType) {
             case ARRAY:
                 elementGetter = InternalArray::getArray;
                 break;
+            case VECTOR:
+                elementGetter = InternalArray::getVector;
+                break;
             case MULTISET:
             case MAP:
                 elementGetter = InternalArray::getMap;

paimon-common/src/main/java/org/apache/paimon/data/InternalRow.java

@@ -150,6 +150,8 @@ static Class<?> getDataClass(DataType type) {
                 return Timestamp.class;
             case ARRAY:
                 return InternalArray.class;
+            case VECTOR:
+                return InternalVector.class;
             case MULTISET:
             case MAP:
                 return InternalMap.class;

paimon-common/src/test/java/org/apache/paimon/data/InternalArrayVectorGetterTest.java

@@ -0,0 +1,104 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.paimon.data;
+
+import org.apache.paimon.data.serializer.InternalArraySerializer;
+import org.apache.paimon.io.DataInputViewStreamWrapper;
+import org.apache.paimon.io.DataOutputViewStreamWrapper;
+import org.apache.paimon.types.FloatType;
+import org.apache.paimon.types.VectorType;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests that ARRAY<VECTOR> is supported by {@link InternalArray} accessors: the {@link
+ * InternalArraySerializer} eagerly builds an element getter, so a missing VECTOR case fails
+ * serializer construction for an accepted DDL type.
+ */
+class InternalArrayVectorGetterTest {
+
+    private static final VectorType VECTOR_TYPE = new VectorType(3, new FloatType());
+
+    @Test
+    void elementGetterReadsVector() {
+        BinaryVector vector = BinaryVector.fromPrimitiveArray(new float[] {1.0f, 2.0f, 3.0f});
+        GenericArray array = new GenericArray(new Object[] {vector});
+
+        InternalArray.ElementGetter getter = InternalArray.createElementGetter(VECTOR_TYPE);
+
+        assertThat(getter.getElementOrNull(array, 0)).isEqualTo(vector);
+    }
+
+    @Test
+    void vectorArrayRoundTripsThroughSerializer() throws Exception {
+        InternalArraySerializer serializer = new InternalArraySerializer(VECTOR_TYPE);
+        // more than one element, with a null between them: only the binary form exercises the
+        // 8-byte variable-length slot and the null bit, and the last vector then starts at an
+        // offset the first one's payload decided
+        GenericArray array =
+                new GenericArray(
+                        new Object[] {
+                            BinaryVector.fromPrimitiveArray(new float[] {4.0f, 5.0f, 6.0f}),
+                            null,
+                            BinaryVector.fromPrimitiveArray(new float[] {7.0f, 8.0f, 9.0f})
+                        });
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        serializer.serialize(array, new DataOutputViewStreamWrapper(out));
+        InternalArray readBack =
+                serializer.deserialize(
+                        new DataInputViewStreamWrapper(
+                                new ByteArrayInputStream(out.toByteArray())));
+
+        assertThat(readBack.size()).isEqualTo(3);
+        assertThat(readBack.isNullAt(1)).isTrue();
+        assertThat(readBack.getVector(0).toFloatArray()).isEqualTo(new float[] {4.0f, 5.0f, 6.0f});
+        assertThat(readBack.getVector(2).toFloatArray()).isEqualTo(new float[] {7.0f, 8.0f, 9.0f});
+
+        // toObjectArray and copy read the binary form through getDataClass and the element
+        // getter; the projection and manifest paths use them, no test did
+        InternalVector[] objects = ((BinaryArray) readBack).toObjectArray(VECTOR_TYPE);
+        assertThat(objects).hasSize(3);
+        assertThat(objects[1]).isNull();
+        assertThat(objects[2].toFloatArray()).isEqualTo(new float[] {7.0f, 8.0f, 9.0f});
+
+        InternalArray copied = serializer.copy(readBack);
+        assertThat(copied.isNullAt(1)).isTrue();
+        assertThat(copied.getVector(2).toFloatArray()).isEqualTo(new float[] {7.0f, 8.0f, 9.0f});
+    }
+
+    @Test
+    void vectorArrayCopyResolvesDataClass() {
+        // copy() of a GenericArray goes through InternalRow.getDataClass(VECTOR) to allocate the
+        // element array; without the VECTOR case that throws "Illegal type", so this pins the
+        // getDataClass fix (the round-trip test above copies raw bytes and never reaches it).
+        InternalArraySerializer serializer = new InternalArraySerializer(VECTOR_TYPE);
+        BinaryVector vector = BinaryVector.fromPrimitiveArray(new float[] {7.0f, 8.0f, 9.0f});
+        GenericArray array = new GenericArray(new Object[] {vector});
+
+        InternalArray copied = serializer.copy(array);
+
+        assertThat(copied.getVector(0).toFloatArray()).isEqualTo(new float[] {7.0f, 8.0f, 9.0f});
+    }
+}