GH-39484: [Java] Support 256 bit decimals in JdbcToArrowUtils

java/adapter/jdbc/src/main/java/org/apache/arrow/adapter/jdbc/JdbcToArrowUtils.java

@@ -45,6 +45,7 @@
 import org.apache.arrow.adapter.jdbc.consumer.BitConsumer;
 import org.apache.arrow.adapter.jdbc.consumer.CompositeJdbcConsumer;
 import org.apache.arrow.adapter.jdbc.consumer.DateConsumer;
+import org.apache.arrow.adapter.jdbc.consumer.Decimal256Consumer;
 import org.apache.arrow.adapter.jdbc.consumer.DecimalConsumer;
 import org.apache.arrow.adapter.jdbc.consumer.DoubleConsumer;
 import org.apache.arrow.adapter.jdbc.consumer.FloatConsumer;
@@ -63,6 +64,7 @@
 import org.apache.arrow.vector.BigIntVector;
 import org.apache.arrow.vector.BitVector;
 import org.apache.arrow.vector.DateDayVector;
+import org.apache.arrow.vector.Decimal256Vector;
 import org.apache.arrow.vector.DecimalVector;
 import org.apache.arrow.vector.FieldVector;
 import org.apache.arrow.vector.Float4Vector;
@@ -169,7 +171,11 @@ public static ArrowType getArrowTypeFromJdbcType(final JdbcFieldInfo fieldInfo,
       case Types.DECIMAL:
         int precision = fieldInfo.getPrecision();
         int scale = fieldInfo.getScale();
-        return new ArrowType.Decimal(precision, scale, 128);
+        if (precision > 38) {
+          return new ArrowType.Decimal(precision, scale, 256);
+        } else {
+          return new ArrowType.Decimal(precision, scale, 128);
+        }
       case Types.REAL:
       case Types.FLOAT:
         return new ArrowType.FloatingPoint(SINGLE);
@@ -463,7 +469,12 @@ public static JdbcConsumer getConsumer(ArrowType arrowType, int columnIndex, boo
         }
       case Decimal:
         final RoundingMode bigDecimalRoundingMode = config.getBigDecimalRoundingMode();
-        return DecimalConsumer.createConsumer((DecimalVector) vector, columnIndex, nullable, bigDecimalRoundingMode);
+        if (((ArrowType.Decimal) arrowType).getBitWidth() == 256) {
+          return Decimal256Consumer.createConsumer((Decimal256Vector) vector, columnIndex, nullable,
+                  bigDecimalRoundingMode);
+        } else {
+          return DecimalConsumer.createConsumer((DecimalVector) vector, columnIndex, nullable, bigDecimalRoundingMode);
+        }
       case FloatingPoint:
         switch (((ArrowType.FloatingPoint) arrowType).getPrecision()) {
           case SINGLE:

java/adapter/jdbc/src/main/java/org/apache/arrow/adapter/jdbc/consumer/Decimal256Consumer.java

@@ -0,0 +1,128 @@
+/*
+ * 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.arrow.adapter.jdbc.consumer;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import org.apache.arrow.vector.Decimal256Vector;
+
+/**
+ * Consumer which consume decimal type values from {@link ResultSet}.
+ * Write the data to {@link org.apache.arrow.vector.Decimal256Vector}.
+ */
+public abstract class Decimal256Consumer extends BaseConsumer<Decimal256Vector> {
+  private final RoundingMode bigDecimalRoundingMode;
+  private final int scale;
+
+  /**
+   * Constructs a new consumer.
+   *
+   * @param vector the underlying vector for the consumer.
+   * @param index  the column id for the consumer.
+   */
+  public Decimal256Consumer(Decimal256Vector vector, int index) {
+    this(vector, index, null);
+  }
+
+  /**
+   * Constructs a new consumer, with optional coercibility.
+   * @param vector the underlying vector for the consumer.
+   * @param index the column index for the consumer.
+   * @param bigDecimalRoundingMode java.math.RoundingMode to be applied if the BigDecimal scale does not match that
+   *                               of the target vector.  Set to null to retain strict matching behavior (scale of
+   *                               source and target vector must match exactly).
+   */
+  public Decimal256Consumer(Decimal256Vector vector, int index, RoundingMode bigDecimalRoundingMode) {
+    super(vector, index);
+    this.bigDecimalRoundingMode = bigDecimalRoundingMode;
+    this.scale = vector.getScale();
+  }
+
+  /**
+   * Creates a consumer for {@link Decimal256Vector}.
+   */
+  public static JdbcConsumer<Decimal256Vector> createConsumer(
+          Decimal256Vector vector,
+          int index,
+          boolean nullable,
+          RoundingMode bigDecimalRoundingMode
+  ) {
+    if (nullable) {
+      return new NullableDecimal256Consumer(vector, index, bigDecimalRoundingMode);
+    } else {
+      return new NonNullableDecimal256Consumer(vector, index, bigDecimalRoundingMode);
+    }
+  }
+
+  protected void set(BigDecimal value) {
+    if (bigDecimalRoundingMode != null && value.scale() != scale) {
+      value = value.setScale(scale, bigDecimalRoundingMode);
+    }
+    vector.set(currentIndex, value);
+  }
+
+
+  /**
+   * Consumer for nullable decimal.
+   */
+  static class NullableDecimal256Consumer extends Decimal256Consumer {
+
+    /**
+     * Instantiate a Decimal256Consumer.
+     */
+    public NullableDecimal256Consumer(Decimal256Vector vector, int index, RoundingMode bigDecimalRoundingMode) {
+      super(vector, index, bigDecimalRoundingMode);
+    }
+
+    @Override
+    public void consume(ResultSet resultSet) throws SQLException {
+      BigDecimal value = resultSet.getBigDecimal(columnIndexInResultSet);
+      if (!resultSet.wasNull()) {
+        // for fixed width vectors, we have allocated enough memory proactively,
+        // so there is no need to call the setSafe method here.
+        set(value);
+      }
+      currentIndex++;
+    }
+  }
+
+  /**
+   * Consumer for non-nullable decimal.
+   */
+  static class NonNullableDecimal256Consumer extends Decimal256Consumer {
+
+    /**
+     * Instantiate a Decimal256Consumer.
+     */
+    public NonNullableDecimal256Consumer(Decimal256Vector vector, int index, RoundingMode bigDecimalRoundingMode) {
+      super(vector, index, bigDecimalRoundingMode);
+    }
+
+    @Override
+    public void consume(ResultSet resultSet) throws SQLException {
+      BigDecimal value = resultSet.getBigDecimal(columnIndexInResultSet);
+      // for fixed width vectors, we have allocated enough memory proactively,
+      // so there is no need to call the setSafe method here.
+      set(value);
+      currentIndex++;
+    }
+  }
+}