ARROW-3966: Moving the metadata flag assignment into the builder.

Author: Mike Pigott

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

@@ -82,15 +82,4 @@ public BaseAllocator getAllocator() {
   public boolean getIncludeMetadata() {
     return includeMetadata;
   }
-
-  /**
-   * Sets whether to include JDBC ResultSet field metadata in the Arrow Schema field metadata.
-   *
-   * @param includeMetadata Whether to include or exclude JDBC metadata in the Arrow Schema field metadata.
-   * @return This instance of the <code>JdbcToArrowConfig</code>, for chaining.
-   */
-  public JdbcToArrowConfig setIncludeMetadata(boolean includeMetadata) {
-    this.includeMetadata = includeMetadata;
-    return this;
-  }
 }

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

@@ -29,6 +29,7 @@
 public class JdbcToArrowConfigBuilder {
   private Calendar calendar;
   private BaseAllocator allocator;
+  private boolean includeMetadata;
 
   /**
    * Default constructor for the <code>JdbcToArrowConfigBuilder}</code>.
@@ -38,6 +39,7 @@ public class JdbcToArrowConfigBuilder {
   public JdbcToArrowConfigBuilder() {
     this.allocator = null;
     this.calendar = null;
+    this.includeMetadata = false;
   }
 
   /**
@@ -63,6 +65,32 @@ public JdbcToArrowConfigBuilder(BaseAllocator allocator, Calendar calendar) {
 
     this.allocator = allocator;
     this.calendar = calendar;
+    this.includeMetadata = false;
+  }
+
+  /**
+   * Constructor for the <code>JdbcToArrowConfigBuilder</code>.  Both the
+   * allocator and calendar are required.  A {@link NullPointerException}
+   * will be thrown if either of those arguments is <code>null</code>.
+   * <p>
+   * The allocator is used to construct Arrow vectors from the JDBC ResultSet.
+   * The calendar is used to determine the time zone of {@link java.sql.Timestamp}
+   * fields and convert {@link java.sql.Date}, {@link java.sql.Time}, and
+   * {@link java.sql.Timestamp} fields to a single, common time zone when reading
+   * from the result set.
+   * </p>
+   * <p>
+   * The <code>includeMetadata</code> argument, if <code>true</code> will cause
+   * various information about each database field to be added to the Vector
+   * Schema's field metadata.
+   * </p>
+   *
+   * @param allocator The Arrow Vector memory allocator.
+   * @param calendar The calendar to use when constructing timestamp fields.
+   */
+  public JdbcToArrowConfigBuilder(BaseAllocator allocator, Calendar calendar, boolean includeMetadata) {
+    this(allocator, calendar);
+    this.includeMetadata = includeMetadata;
   }
 
   /**
@@ -90,6 +118,17 @@ public JdbcToArrowConfigBuilder setCalendar(Calendar calendar) {
     return this;
   }
 
+  /**
+   * Sets whether to include JDBC ResultSet field metadata in the Arrow Schema field metadata.
+   *
+   * @param includeMetadata Whether to include or exclude JDBC metadata in the Arrow Schema field metadata.
+   * @return This instance of the <code>JdbcToArrowConfig</code>, for chaining.
+   */
+  public JdbcToArrowConfigBuilder setIncludeMetadata(boolean includeMetadata) {
+    this.includeMetadata = includeMetadata;
+    return this;
+  }
+
   /**
    * This builds the {@link JdbcToArrowConfig} from the provided
    * {@link BaseAllocator} and {@link Calendar}.
@@ -98,6 +137,6 @@ public JdbcToArrowConfigBuilder setCalendar(Calendar calendar) {
    * @throws NullPointerException if either the allocator or calendar was not set.
    */
   public JdbcToArrowConfig build() {
-    return new JdbcToArrowConfig(allocator, calendar, false);
+    return new JdbcToArrowConfig(allocator, calendar, includeMetadata);
   }
 }

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/JdbcToArrowConfigTest.java

@@ -93,14 +93,17 @@ public void testConfig() {
   }
 
   @Test public void testIncludeMetadata() {
-    JdbcToArrowConfig config = new JdbcToArrowConfig(allocator, calendar, false);
+    JdbcToArrowConfigBuilder builder = new JdbcToArrowConfigBuilder(allocator, calendar, false);
+
+    JdbcToArrowConfig config = builder.build();
     assertFalse(config.getIncludeMetadata());
 
-    config.setIncludeMetadata(true);
+    builder.setIncludeMetadata(true);
+    config = builder.build();
     assertTrue(config.getIncludeMetadata());
 
-    config.setIncludeMetadata(false);
-    assertFalse(config.getIncludeMetadata());
+    config = new JdbcToArrowConfigBuilder(allocator, calendar, true).build();
+    assertTrue(config.getIncludeMetadata());
 
     config = new JdbcToArrowConfig(allocator, calendar, true);
     assertTrue(config.getIncludeMetadata());

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/h2/JdbcToArrowCharSetTest.java

@@ -133,8 +133,7 @@ public void testJdbcToArroValues() throws SQLException, IOException {
 
   @Test
   public void testJdbcSchemaMetadata() throws SQLException {
-    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance()).build();
-    config.setIncludeMetadata(true);
+    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance(), true).build();
     ResultSetMetaData rsmd = conn.createStatement().executeQuery(table.getQuery()).getMetaData();
     Schema schema = JdbcToArrowUtils.jdbcToArrowSchema(rsmd, config);
     JdbcToArrowTestHelper.assertFieldMetadataMatchesResultSetMetadata(rsmd, schema);

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/h2/JdbcToArrowDataTypesTest.java

@@ -159,8 +159,7 @@ public void testJdbcToArroValues() throws SQLException, IOException {
 
   @Test
   public void testJdbcSchemaMetadata() throws SQLException {
-    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance()).build();
-    config.setIncludeMetadata(true);
+    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance(), true).build();
     ResultSetMetaData rsmd = conn.createStatement().executeQuery(table.getQuery()).getMetaData();
     Schema schema = JdbcToArrowUtils.jdbcToArrowSchema(rsmd, config);
     JdbcToArrowTestHelper.assertFieldMetadataMatchesResultSetMetadata(rsmd, schema);

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/h2/JdbcToArrowNullTest.java

@@ -116,8 +116,7 @@ public void testJdbcToArroValues() throws SQLException, IOException {
 
   @Test
   public void testJdbcSchemaMetadata() throws SQLException {
-    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance()).build();
-    config.setIncludeMetadata(true);
+    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance(), true).build();
     ResultSetMetaData rsmd = conn.createStatement().executeQuery(table.getQuery()).getMetaData();
     Schema schema = JdbcToArrowUtils.jdbcToArrowSchema(rsmd, config);
     JdbcToArrowTestHelper.assertFieldMetadataMatchesResultSetMetadata(rsmd, schema);

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/h2/JdbcToArrowTest.java

@@ -150,8 +150,7 @@ public void testJdbcToArroValues() throws SQLException, IOException {
 
   @Test
   public void testJdbcSchemaMetadata() throws SQLException {
-    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance()).build();
-    config.setIncludeMetadata(true);
+    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), Calendar.getInstance(), true).build();
     ResultSetMetaData rsmd = conn.createStatement().executeQuery(table.getQuery()).getMetaData();
     Schema schema = JdbcToArrowUtils.jdbcToArrowSchema(rsmd, config);
     JdbcToArrowTestHelper.assertFieldMetadataMatchesResultSetMetadata(rsmd, schema);

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/h2/JdbcToArrowTimeZoneTest.java

@@ -127,8 +127,7 @@ public void testJdbcToArroValues() throws SQLException, IOException {
   @Test
   public void testJdbcSchemaMetadata() throws SQLException {
     Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone(table.getTimezone()));
-    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), calendar).build();
-    config.setIncludeMetadata(true);
+    JdbcToArrowConfig config = new JdbcToArrowConfigBuilder(new RootAllocator(0), calendar, true).build();
     ResultSetMetaData rsmd = conn.createStatement().executeQuery(table.getQuery()).getMetaData();
     Schema schema = JdbcToArrowUtils.jdbcToArrowSchema(rsmd, config);
     JdbcToArrowTestHelper.assertFieldMetadataMatchesResultSetMetadata(rsmd, schema);