Creating a configuration class for the JDBC-to-Arrow converter.

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

@@ -89,7 +89,9 @@ public static VectorSchemaRoot sqlToArrow(Connection connection, String query, B
     Preconditions.checkArgument(query != null && query.length() > 0, "SQL query can not be null or empty");
     Preconditions.checkNotNull(allocator, "Memory allocator object can not be null");
 
-    return sqlToArrow(connection, query, allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+    JdbcToArrowConfig config =
+            new JdbcToArrowConfig(allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+    return sqlToArrow(connection, query, config);
   }
 
   /**
@@ -115,8 +117,18 @@ public static VectorSchemaRoot sqlToArrow(
     Preconditions.checkNotNull(allocator, "Memory allocator object can not be null");
     Preconditions.checkNotNull(calendar, "Calendar object can not be null");
 
+    return sqlToArrow(connection, query, new JdbcToArrowConfig(allocator, calendar));
+  }
+
+  public static VectorSchemaRoot sqlToArrow(Connection connection, String query, JdbcToArrowConfig config)
+      throws SQLException, IOException {
+    Preconditions.checkNotNull(connection, "JDBC connection object can not be null");
+    Preconditions.checkArgument(query != null && query.length() > 0, "SQL query can not be null or empty");
+    Preconditions.checkNotNull(config, "The configuration cannot be null");
+    Preconditions.checkArgument(config.isValid(), "The configuration must be valid");
+
     try (Statement stmt = connection.createStatement()) {
-      return sqlToArrow(stmt.executeQuery(query), allocator, calendar);
+      return sqlToArrow(stmt.executeQuery(query), config);
     }
   }
 
@@ -147,7 +159,9 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, BaseAllocator all
     Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
     Preconditions.checkNotNull(allocator, "Memory Allocator object can not be null");
 
-    return sqlToArrow(resultSet, allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+    JdbcToArrowConfig config = 
+            new JdbcToArrowConfig(allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+    return sqlToArrow(resultSet, config);
   }
 
   /**
@@ -162,10 +176,7 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, Calendar calendar
     Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
     Preconditions.checkNotNull(calendar, "Calendar object can not be null");
 
-    RootAllocator rootAllocator = new RootAllocator(Integer.MAX_VALUE);
-    VectorSchemaRoot root = sqlToArrow(resultSet, rootAllocator, calendar);
-
-    return root;
+    return sqlToArrow(resultSet, new JdbcToArrowConfig(new RootAllocator(Integer.MAX_VALUE), calendar));
   }
 
   /**
@@ -183,9 +194,18 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, BaseAllocator all
     Preconditions.checkNotNull(allocator, "Memory Allocator object can not be null");
     Preconditions.checkNotNull(calendar, "Calendar object can not be null");
 
+    return sqlToArrow(resultSet, new JdbcToArrowConfig(allocator, calendar));
+  }
+
+  public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, JdbcToArrowConfig config)
+      throws SQLException, IOException {
+    Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
+    Preconditions.checkNotNull(config, "The configuration cannot be null");
+    Preconditions.checkArgument(config.isValid(), "The configuration must be valid");
+
     VectorSchemaRoot root = VectorSchemaRoot.create(
-            JdbcToArrowUtils.jdbcToArrowSchema(resultSet.getMetaData(), calendar), allocator);
-    JdbcToArrowUtils.jdbcToArrowVectors(resultSet, root, calendar);
+            JdbcToArrowUtils.jdbcToArrowSchema(resultSet.getMetaData(), config.getCalendar()), config.getAllocator());
+    JdbcToArrowUtils.jdbcToArrowVectors(resultSet, root, config.getCalendar());
     return root;
   }
 }

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

@@ -0,0 +1,75 @@
+/*
+ * 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;
+
+import java.util.Calendar;
+
+import org.apache.arrow.memory.BaseAllocator;
+
+import com.google.common.base.Preconditions;
+
+/**
+ * This class configures the JDBC-to-Arrow conversion process.
+ */
+public final class JdbcToArrowConfig {
+  private Calendar calendar;
+  private BaseAllocator allocator;
+
+  public JdbcToArrowConfig(BaseAllocator allocator, Calendar calendar) {
+    Preconditions.checkNotNull(allocator, "Memory allocator cannot be null");
+    Preconditions.checkNotNull(calendar, "Calendar object can not be null");
+
+    this.allocator = allocator;
+    this.calendar = calendar;
+  }
+
+  /**
+   * The calendar to use when defining Arrow Timestamp fields
+   * and retrieving time-based fields from the database.
+   * @return the calendar.
+   */
+  public Calendar getCalendar() {
+    return calendar;
+  }
+
+  /**
+   * @param calendar the calendar to set.
+   */
+  public void setCalendar(Calendar calendar) {
+    this.calendar = calendar;
+  }
+
+  /**
+   * The Arrow memory allocator.
+   * @return the allocator.
+   */
+  public BaseAllocator getAllocator() {
+    return allocator;
+  }
+
+  /**
+   * @param allocator the allocator to set.
+   */
+  public void setAllocator(BaseAllocator allocator) {
+    this.allocator = allocator;
+  }
+
+  public boolean isValid() {
+    return (calendar != null) || (allocator != null);
+  }
+}