ARROW-17883: [Java] implement immutable table

java/c/src/main/java/org/apache/arrow/c/Data.java

@@ -28,6 +28,7 @@
 import org.apache.arrow.vector.dictionary.DictionaryProvider;
 import org.apache.arrow.vector.ipc.ArrowReader;
 import org.apache.arrow.vector.ipc.message.ArrowRecordBatch;
+import org.apache.arrow.vector.table.Table;
 import org.apache.arrow.vector.types.pojo.ArrowType;
 import org.apache.arrow.vector.types.pojo.ArrowType.ArrowTypeID;
 import org.apache.arrow.vector.types.pojo.Field;
@@ -114,22 +115,76 @@ public static void exportVector(BufferAllocator allocator, FieldVector vector, D
     exporter.export(out, vector, provider);
   }
 
+  /**
+   * Export the current contents of a Java Table using the C data
+   * interface format.
+   * <p>
+   * The table is exported as if it were a struct array. The
+   * resulting ArrowArray struct keeps the record batch data and buffers alive
+   * until its release callback is called by the consumer.
+   *
+   * @param allocator Buffer allocator for allocating C data interface fields
+   * @param table     Table to export
+   * @param out       C struct where to export the record batch
+   */
+  public static void exportTable(BufferAllocator allocator, Table table, ArrowArray out) {
+    exportTable(allocator, table, table.getDictionaryProvider(), out, null);
+  }
+
+  /**
+   * Export the current contents of a Java Table using the C data
+   * interface format.
+   * <p>
+   * The table is exported as if it were a struct array. The
+   * resulting ArrowArray struct keeps the record batch data and buffers alive
+   * until its release callback is called by the consumer.
+   *
+   * @param allocator Buffer allocator for allocating C data interface fields
+   * @param table     Table to export
+   * @param provider  Dictionary provider for dictionary encoded vectors
+   *                  (optional)
+   * @param out       C struct where to export the record batch
+   */
+  public static void exportTable(BufferAllocator allocator, Table table,
+      DictionaryProvider provider, ArrowArray out) {
+    exportTable(allocator, table, provider, out, null);
+  }
+
+  /**
+   * Export the current contents of a Java Table using the C data interface format.
+   * <p>
+   * The table is exported as if it were a struct array. The
+   * resulting ArrowArray struct keeps the record batch data and buffers alive
+   * until its release callback is called by the consumer.
+   *
+   * @param allocator Buffer allocator for allocating C data interface fields
+   * @param table     Table to export
+   * @param provider  Dictionary provider for dictionary encoded vectors
+   *                  (optional)
+   * @param out       C struct where to export the record batch
+   * @param outSchema C struct where to export the record batch schema (optional)
+   */
+  public static void exportTable(BufferAllocator allocator, Table table,
+                                 DictionaryProvider provider, ArrowArray out, ArrowSchema outSchema) {
+    exportVectorSchemaRoot(allocator, table.toVectorSchemaRoot(), provider, out, outSchema);
+  }
+
   /**
    * Export the current contents of a Java VectorSchemaRoot using the C data
    * interface format.
    * <p>
    * The vector schema root is exported as if it were a struct array. The
    * resulting ArrowArray struct keeps the record batch data and buffers alive
    * until its release callback is called by the consumer.
-   * 
+   *
    * @param allocator Buffer allocator for allocating C data interface fields
    * @param vsr       Vector schema root to export
    * @param provider  Dictionary provider for dictionary encoded vectors
    *                  (optional)
    * @param out       C struct where to export the record batch
    */
   public static void exportVectorSchemaRoot(BufferAllocator allocator, VectorSchemaRoot vsr,
-      DictionaryProvider provider, ArrowArray out) {
+                                            DictionaryProvider provider, ArrowArray out) {
     exportVectorSchemaRoot(allocator, vsr, provider, out, null);
   }
 

java/c/src/test/java/org/apache/arrow/c/RoundtripTest.java

@@ -90,6 +90,7 @@
 import org.apache.arrow.vector.holders.IntervalDayHolder;
 import org.apache.arrow.vector.holders.NullableLargeVarBinaryHolder;
 import org.apache.arrow.vector.holders.NullableUInt4Holder;
+import org.apache.arrow.vector.table.Table;
 import org.apache.arrow.vector.types.TimeUnit;
 import org.apache.arrow.vector.types.Types.MinorType;
 import org.apache.arrow.vector.types.pojo.ArrowType;
@@ -657,6 +658,39 @@ public void testVectorSchemaRoot() {
     imported.close();
   }
 
+  /**
+   * Tests exporting Table and importing back to VSR. Importing back to Table is not supported at present.
+   */
+  @Test
+  public void testTable() {
+    VectorSchemaRoot imported;
+
+    // Consumer allocates empty structures
+    try (ArrowSchema consumerArrowSchema = ArrowSchema.allocateNew(allocator);
+        ArrowArray consumerArrowArray = ArrowArray.allocateNew(allocator)) {
+      try (
+          VectorSchemaRoot vsr = createTestVSR();
+          Table table = new Table(vsr);
+      ) {
+        // Producer creates structures from existing memory pointers
+        try (ArrowSchema arrowSchema = ArrowSchema.wrap(consumerArrowSchema.memoryAddress());
+            ArrowArray arrowArray = ArrowArray.wrap(consumerArrowArray.memoryAddress())) {
+          // Producer exports vector into the C Data Interface structures
+          Data.exportTable(allocator, table, arrowArray);
+        }
+      }
+      // Consumer imports vector
+      imported = Data.importVectorSchemaRoot(allocator, consumerArrowArray, consumerArrowSchema, null);
+    }
+
+    // Ensure that imported VectorSchemaRoot is valid even after C Data Interface
+    // structures are closed
+    try (VectorSchemaRoot original = createTestVSR()) {
+      assertTrue(imported.equals(original));
+    }
+    imported.close();
+  }
+
   @Test
   public void testVectorSchemaRootWithDuplicatedFieldNames() {
     VectorSchemaRoot imported;

java/pom.xml

@@ -303,9 +303,9 @@
             <version>8.19</version>
           </dependency>
           <dependency>
-              <groupId>org.slf4j</groupId>
-              <artifactId>jcl-over-slf4j</artifactId>
-              <version>1.7.5</version>
+            <groupId>org.slf4j</groupId>
+            <artifactId>jcl-over-slf4j</artifactId>
+            <version>1.7.5</version>
           </dependency>
         </dependencies>
         <executions>
@@ -749,7 +749,7 @@
       <!-- Use the version of arrow-vector that shades flatbuffers and packages format -->
       <id>shade-flatbuffers</id>
       <properties>
-       <arrow.vector.classifier>shade-format-flatbuffers</arrow.vector.classifier>
+        <arrow.vector.classifier>shade-format-flatbuffers</arrow.vector.classifier>
       </properties>
     </profile>
 
@@ -763,7 +763,7 @@
       <activation>
         <jdk>1.8</jdk>
         <property>
-           <name>!m2e.version</name>
+          <name>!m2e.version</name>
         </property>
       </activation>
       <build>