ARROW-3966 [Java] JDBC Column Metadata in Arrow Field Metadata

https://issues.apache.org/jira/browse/ARROW-3966

This change includes apache#3133, and supports a new configuration item called "Include Metadata."  If true, metadata from the JDBC ResultSetMetaData object is pulled along to the Schema Field Metadata.  For now, this includes:
* Catalog Name
* Table Name
* Column Name
* Column Type Name

Author: Mike Pigott <mpigott@gmail.com>
Author: Michael Pigott <mikepigott@users.noreply.github.com>

Closes apache#3134 from mikepigott/jdbc-column-metadata and squashes the following commits:

02f2f34 <Mike Pigott> ARROW-3966: Picking up lost change to support null calendars.
7049c36 <Mike Pigott> Merge branch 'master' into jdbc-column-metadata
e9a9b2b <Michael Pigott> Merge pull request #6 from apache/master
65741a9 <Mike Pigott> ARROW-3966: Code review feedback
cc6cc88 <Mike Pigott> ARROW-3966: Using a 1:N loop instead of a 0:N-1 loop for fewer index offsets in code.
cfb2ba6 <Mike Pigott> ARROW-3966: Using a helper method for building a UTC calendar with root locale.
2928513 <Mike Pigott> ARROW-3966: Moving the metadata flag assignment into the builder.
69022c2 <Mike Pigott> ARROW-3966: Fixing merge.
4a6de86 <Mike Pigott> Merge branch 'master' into jdbc-column-metadata
509a1cc <Michael Pigott> Merge pull request #5 from apache/master
789c8c8 <Michael Pigott> Merge pull request #4 from apache/master
e5b19ee <Michael Pigott> Merge pull request #3 from apache/master
3b17c29 <Michael Pigott> Merge pull request #2 from apache/master
d847ebc <Mike Pigott> Fixing file location
1ceac9e <Mike Pigott> Merge branch 'master' into jdbc-column-metadata
881c6c8 <Michael Pigott> Merge pull request #1 from apache/master
03091a8 <Mike Pigott> Unit tests for including result set metadata.
72d64cc <Mike Pigott> Affirming the field metadata is empty when the configuration excludes field metadata.
7b4527c <Mike Pigott> Test for the include-metadata flag in the configuration.
7e9ce37 <Mike Pigott> Merge branch 'jdbc-to-arrow-config' into jdbc-column-metadata
bb3165b <Mike Pigott> Updating the function calls to use the JdbcToArrowConfig versions.
a6fb1be <Mike Pigott> Fixing function call
5bfd6a2 <Mike Pigott> Merge branch 'jdbc-to-arrow-config' into jdbc-column-metadata
68c91e7 <Mike Pigott> Modifying the jdbcToArrowSchema and jdbcToArrowVectors methods to receive JdbcToArrowConfig objects.
b5b0cb1 <Mike Pigott> Merge branch 'jdbc-to-arrow-config' into jdbc-column-metadata
8d6cf00 <Mike Pigott> Documentation for public static VectorSchemaRoot sqlToArrow(Connection connection, String query, JdbcToArrowConfig config)
4f1260c <Mike Pigott> Adding documentation for public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, JdbcToArrowConfig config)
e34a9e7 <Mike Pigott> Fixing formatting.
fe097c8 <Mike Pigott> Merge branch 'jdbc-to-arrow-config' into jdbc-column-metadata
df632e3 <Mike Pigott> Updating the SQL tests to include JdbcToArrowConfig versions.
b270044 <Mike Pigott> Updated validaton & documentation, and unit tests for the new JdbcToArrowConfig.
da77cbe <Mike Pigott> Creating a configuration class for the JDBC-to-Arrow converter.
a78c770 <Mike Pigott> Updating Javadocs.
523387f <Mike Pigott> Updating the API to support an optional 'includeMetadata' field.
5af1b5b <Mike Pigott> Separating out the field-type creation from the field creation.

Author: Mike Pigott

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

@@ -0,0 +1,27 @@
+/*
+ * 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;
+
+public class Constants {
+
+  public static final String SQL_CATALOG_NAME_KEY = "SQL_CATALOG_NAME";
+  public static final String SQL_TABLE_NAME_KEY = "SQL_TABLE_NAME";
+  public static final String SQL_COLUMN_NAME_KEY = "SQL_COLUMN_NAME";
+  public static final String SQL_TYPE_KEY = "SQL_TYPE";
+
+}

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

@@ -23,8 +23,6 @@
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.Calendar;
-import java.util.Locale;
-import java.util.TimeZone;
 
 import org.apache.arrow.memory.BaseAllocator;
 import org.apache.arrow.memory.RootAllocator;
@@ -90,7 +88,7 @@ public static VectorSchemaRoot sqlToArrow(Connection connection, String query, B
     Preconditions.checkNotNull(allocator, "Memory allocator object can not be null");
 
     JdbcToArrowConfig config =
-            new JdbcToArrowConfig(allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+            new JdbcToArrowConfig(allocator, JdbcToArrowUtils.getUtcCalendar(), false);
     return sqlToArrow(connection, query, config);
   }
 
@@ -112,12 +110,13 @@ public static VectorSchemaRoot sqlToArrow(
       String query,
       BaseAllocator allocator,
       Calendar calendar) 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(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));
+    return sqlToArrow(connection, query, new JdbcToArrowConfig(allocator, calendar, false));
   }
 
   /**
@@ -154,7 +153,7 @@ public static VectorSchemaRoot sqlToArrow(Connection connection, String query, J
   public static VectorSchemaRoot sqlToArrow(ResultSet resultSet) throws SQLException, IOException {
     Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
 
-    return sqlToArrow(resultSet, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+    return sqlToArrow(resultSet, JdbcToArrowUtils.getUtcCalendar());
   }
 
   /**
@@ -171,7 +170,7 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, BaseAllocator all
     Preconditions.checkNotNull(allocator, "Memory Allocator object can not be null");
 
     JdbcToArrowConfig config = 
-            new JdbcToArrowConfig(allocator, Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT));
+            new JdbcToArrowConfig(allocator, JdbcToArrowUtils.getUtcCalendar(), false);
     return sqlToArrow(resultSet, config);
   }
 
@@ -186,7 +185,7 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, BaseAllocator all
   public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, Calendar calendar) throws SQLException, IOException {
     Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
 
-    return sqlToArrow(resultSet, new JdbcToArrowConfig(new RootAllocator(Integer.MAX_VALUE), calendar));
+    return sqlToArrow(resultSet, new JdbcToArrowConfig(new RootAllocator(Integer.MAX_VALUE), calendar, false));
   }
 
   /**
@@ -198,12 +197,15 @@ public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, Calendar calendar
    * @return Arrow Data Objects {@link VectorSchemaRoot}
    * @throws SQLException on error
    */
-  public static VectorSchemaRoot sqlToArrow(ResultSet resultSet, BaseAllocator allocator, Calendar calendar)
+  public static VectorSchemaRoot sqlToArrow(
+          ResultSet resultSet,
+          BaseAllocator allocator,
+          Calendar calendar)
       throws SQLException, IOException {
     Preconditions.checkNotNull(resultSet, "JDBC ResultSet object can not be null");
     Preconditions.checkNotNull(allocator, "Memory Allocator object can not be null");
 
-    return sqlToArrow(resultSet, new JdbcToArrowConfig(allocator, calendar));
+    return sqlToArrow(resultSet, new JdbcToArrowConfig(allocator, calendar, false));
   }
 
   /**

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

@@ -37,20 +37,23 @@
 public final class JdbcToArrowConfig {
   private Calendar calendar;
   private BaseAllocator allocator;
+  private boolean includeMetadata;
 
   /**
    * Constructs a new configuration from the provided allocator and calendar.  The <code>allocator</code>
    * is used when constructing the Arrow vectors from the ResultSet, and the calendar is used to define
    * Arrow Timestamp fields, and to read time-based fields from the JDBC <code>ResultSet</code>. 
    *
-   * @param allocator The memory allocator to construct the Arrow vectors with.
-   * @param calendar The calendar to use when constructing Timestamp fields and reading time-based results.
+   * @param allocator       The memory allocator to construct the Arrow vectors with.
+   * @param calendar        The calendar to use when constructing Timestamp fields and reading time-based results.
+   * @param includeMetadata Whether to include JDBC field metadata in the Arrow Schema Field metadata.
    */
-  JdbcToArrowConfig(BaseAllocator allocator, Calendar calendar) {
+  JdbcToArrowConfig(BaseAllocator allocator, Calendar calendar, boolean includeMetadata) {
     Preconditions.checkNotNull(allocator, "Memory allocator cannot be null");
 
     this.allocator = allocator;
     this.calendar = calendar;
+    this.includeMetadata = includeMetadata;
   }
 
   /**
@@ -70,4 +73,13 @@ public Calendar getCalendar() {
   public BaseAllocator getAllocator() {
     return allocator;
   }
+
+  /**
+   * Whether to include JDBC ResultSet field metadata in the Arrow Schema field metadata.
+   *
+   * @return <code>true</code> to include field metadata, <code>false</code> to exclude it.
+   */
+  public boolean shouldIncludeMetadata() {
+    return includeMetadata;
+  }
 }

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;
   }
 
   /**
@@ -62,6 +64,32 @@ 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;
   }
 
   /**
@@ -87,6 +115,17 @@ 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}.
@@ -95,6 +134,6 @@ public JdbcToArrowConfigBuilder setCalendar(Calendar calendar) {
    * @throws NullPointerException if either the allocator or calendar was not set.
    */
   public JdbcToArrowConfig build() {
-    return new JdbcToArrowConfig(allocator, calendar);
+    return new JdbcToArrowConfig(allocator, calendar, includeMetadata);
   }
 }

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

@@ -36,7 +36,11 @@
 import java.sql.Types;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TimeZone;
 
 import org.apache.arrow.memory.RootAllocator;
 import org.apache.arrow.vector.BaseFixedWidthVector;
@@ -103,7 +107,14 @@ public static Schema jdbcToArrowSchema(ResultSetMetaData rsmd, Calendar calendar
     Preconditions.checkNotNull(rsmd, "JDBC ResultSetMetaData object can't be null");
     Preconditions.checkNotNull(calendar, "Calendar object can't be null");
 
-    return jdbcToArrowSchema(rsmd, new JdbcToArrowConfig(new RootAllocator(0), calendar));
+    return jdbcToArrowSchema(rsmd, new JdbcToArrowConfig(new RootAllocator(0), calendar, false));
+  }
+
+  /**
+   * Returns the instance of a {java.util.Calendar} with the UTC time zone and root locale.
+   */
+  public static Calendar getUtcCalendar() {
+    return Calendar.getInstance(TimeZone.getTimeZone("UTC"), Locale.ROOT);
   }
 
   /**
@@ -145,78 +156,103 @@ public static Schema jdbcToArrowSchema(ResultSetMetaData rsmd, JdbcToArrowConfig
     Preconditions.checkNotNull(rsmd, "JDBC ResultSetMetaData object can't be null");
     Preconditions.checkNotNull(config, "The configuration object must not be null");
 
+    final String timezone;
+    if (config.getCalendar() != null) {
+      timezone = config.getCalendar().getTimeZone().getID();
+    } else {
+      timezone = null;
+    }
+
     List<Field> fields = new ArrayList<>();
     int columnCount = rsmd.getColumnCount();
     for (int i = 1; i <= columnCount; i++) {
-      String columnName = rsmd.getColumnName(i);
+      final String columnName = rsmd.getColumnName(i);
+      final FieldType fieldType;
+
+      final Map<String, String> metadata;
+      if (config.shouldIncludeMetadata()) {
+        metadata = new HashMap<>();
+        metadata.put(Constants.SQL_CATALOG_NAME_KEY, rsmd.getCatalogName(i));
+        metadata.put(Constants.SQL_TABLE_NAME_KEY, rsmd.getTableName(i));
+        metadata.put(Constants.SQL_COLUMN_NAME_KEY, columnName);
+        metadata.put(Constants.SQL_TYPE_KEY, rsmd.getColumnTypeName(i));
+
+      } else {
+        metadata = null;
+      }
+
       switch (rsmd.getColumnType(i)) {
         case Types.BOOLEAN:
         case Types.BIT:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Bool()), null));
+          fieldType = new FieldType(true, new ArrowType.Bool(), null, metadata);
           break;
         case Types.TINYINT:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Int(8, true)), null));
+          fieldType = new FieldType(true, new ArrowType.Int(8, true), null, metadata);
           break;
         case Types.SMALLINT:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Int(16, true)), null));
+          fieldType = new FieldType(true, new ArrowType.Int(16, true), null, metadata);
           break;
         case Types.INTEGER:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Int(32, true)), null));
+          fieldType = new FieldType(true, new ArrowType.Int(32, true), null, metadata);
           break;
         case Types.BIGINT:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Int(64, true)), null));
+          fieldType = new FieldType(true, new ArrowType.Int(64, true), null, metadata);
           break;
         case Types.NUMERIC:
         case Types.DECIMAL:
           int precision = rsmd.getPrecision(i);
           int scale = rsmd.getScale(i);
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Decimal(precision, scale)), null));
+          fieldType = new FieldType(true, new ArrowType.Decimal(precision, scale), null, metadata);
           break;
         case Types.REAL:
         case Types.FLOAT:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.FloatingPoint(SINGLE)), null));
+          fieldType = new FieldType(true, new ArrowType.FloatingPoint(SINGLE), null, metadata);
           break;
         case Types.DOUBLE:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.FloatingPoint(DOUBLE)), null));
+          fieldType = new FieldType(true, new ArrowType.FloatingPoint(DOUBLE), null, metadata);
           break;
         case Types.CHAR:
         case Types.NCHAR:
         case Types.VARCHAR:
         case Types.NVARCHAR:
         case Types.LONGVARCHAR:
         case Types.LONGNVARCHAR:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Utf8()), null));
+        case Types.CLOB:
+          fieldType = new FieldType(true, new ArrowType.Utf8(), null, metadata);
           break;
         case Types.DATE:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Date(DateUnit.MILLISECOND)), null));
+          fieldType = new FieldType(true, new ArrowType.Date(DateUnit.MILLISECOND), null, metadata);
           break;
         case Types.TIME:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Time(TimeUnit.MILLISECOND, 32)), null));
+          fieldType = new FieldType(true, new ArrowType.Time(TimeUnit.MILLISECOND, 32), null, metadata);
           break;
         case Types.TIMESTAMP:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Timestamp(TimeUnit.MILLISECOND,
-              config.getCalendar().getTimeZone().getID())), null));
+          fieldType =
+              new FieldType(
+                  true,
+                  new ArrowType.Timestamp(TimeUnit.MILLISECOND, timezone),
+                  null,
+                  metadata);
           break;
         case Types.BINARY:
         case Types.VARBINARY:
         case Types.LONGVARBINARY:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Binary()), null));
-          break;
-        case Types.ARRAY:
-          // TODO Need to handle this type
-          // fields.add(new Field("list", FieldType.nullable(new ArrowType.List()), null));
-          break;
-        case Types.CLOB:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Utf8()), null));
-          break;
         case Types.BLOB:
-          fields.add(new Field(columnName, FieldType.nullable(new ArrowType.Binary()), null));
+          fieldType = new FieldType(true, new ArrowType.Binary(), null, metadata);
           break;
 
+        case Types.ARRAY:
+            // TODO Need to handle this type
+            // fields.add(new Field("list", FieldType.nullable(new ArrowType.List()), null));
         default:
           // no-op, shouldn't get here
+          fieldType = null;
           break;
       }
+
+      if (fieldType != null) {
+        fields.add(new Field(columnName, fieldType, null));
+      }
     }
 
     return new Schema(fields, null);
@@ -250,7 +286,7 @@ public static void jdbcToArrowVectors(ResultSet rs, VectorSchemaRoot root, Calen
     Preconditions.checkNotNull(rs, "JDBC ResultSet object can't be null");
     Preconditions.checkNotNull(root, "JDBC ResultSet object can't be null");
 
-    jdbcToArrowVectors(rs, root, new JdbcToArrowConfig(new RootAllocator(0), calendar));
+    jdbcToArrowVectors(rs, root, new JdbcToArrowConfig(new RootAllocator(0), calendar, false));
   }
 
   /**