Added an interface for Iterable ValueVectors

* The new interface indicates that a ValueVector is iterable
* Contains default methods for getting an Iterator and Iterable

java/dataset/pom.xml

@@ -161,6 +161,11 @@ under the License.
       <version>2.15.1</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.hamcrest</groupId>
+      <artifactId>hamcrest</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
   <build>
     <resources>

java/dataset/src/test/java/org/apache/arrow/dataset/substrait/TestAceroSubstraitConsumer.java

@@ -16,6 +16,7 @@
  */
 package org.apache.arrow.dataset.substrait;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
@@ -38,11 +39,14 @@
 import org.apache.arrow.dataset.scanner.Scanner;
 import org.apache.arrow.dataset.source.Dataset;
 import org.apache.arrow.dataset.source.DatasetFactory;
+import org.apache.arrow.vector.ValueIterableVector;
 import org.apache.arrow.vector.ipc.ArrowReader;
 import org.apache.arrow.vector.types.pojo.ArrowType;
 import org.apache.arrow.vector.types.pojo.Field;
 import org.apache.arrow.vector.types.pojo.FieldType;
 import org.apache.arrow.vector.types.pojo.Schema;
+import org.apache.arrow.vector.util.Text;
+import org.hamcrest.collection.IsIterableContainingInOrder;
 import org.junit.ClassRule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -289,13 +293,13 @@ public void testRunExtendedExpressionsFilter() throws Exception {
       int rowcount = 0;
       while (reader.loadNextBatch()) {
         rowcount += reader.getVectorSchemaRoot().getRowCount();
-        assertTrue(reader.getVectorSchemaRoot().getVector("id").toString().equals("[19, 1, 11]"));
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("name")
-                .toString()
-                .equals("[value_19, value_1, value_11]"));
+        final ValueIterableVector<Integer> idVector =
+            (ValueIterableVector<Integer>) reader.getVectorSchemaRoot().getVector("id");
+        assertThat(idVector.getValueIterable(), IsIterableContainingInOrder.contains(19, 1, 11));
+        final ValueIterableVector<Text> nameVector =
+            (ValueIterableVector<Text>) reader.getVectorSchemaRoot().getVector("name");
+        assertThat(nameVector.getValueIterable(), IsIterableContainingInOrder.contains(
+            new Text("value_19"), new Text("value_1"), new Text("value_11")));
       }
       assertEquals(3, rowcount);
     }
@@ -442,20 +446,16 @@ public void testRunExtendedExpressionsProjection() throws Exception {
       assertEquals(schema.getFields(), reader.getVectorSchemaRoot().getSchema().getFields());
       int rowcount = 0;
       while (reader.loadNextBatch()) {
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("add_two_to_column_a")
-                .toString()
-                .equals("[21, 3, 13, 23, 47]"));
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("concat_column_a_and_b")
-                .toString()
-                .equals(
-                    "[value_19 - value_19, value_1 - value_1, value_11 - value_11, "
-                        + "value_21 - value_21, value_45 - value_45]"));
+        final ValueIterableVector<Integer> sumVector =
+            (ValueIterableVector<Integer>) reader.getVectorSchemaRoot().getVector("add_two_to_column_a");
+        assertThat(sumVector.getValueIterable(), IsIterableContainingInOrder.contains(21, 3, 13, 23, 47));
+        final ValueIterableVector<Text> nameVector =
+            (ValueIterableVector<Text>) reader.getVectorSchemaRoot().getVector("concat_column_a_and_b");
+        assertThat(nameVector.getValueIterable(),
+            IsIterableContainingInOrder.contains(
+                new Text("value_19 - value_19"), new Text("value_1 - value_1"),
+                new Text("value_11 - value_11"), new Text("value_21 - value_21"),
+                new Text("value_45 - value_45")));
         rowcount += reader.getVectorSchemaRoot().getRowCount();
       }
       assertEquals(5, rowcount);
@@ -506,12 +506,10 @@ public void testRunExtendedExpressionsProjectionWithFilterInsteadOfProjectionExc
       assertEquals(schema.getFields(), reader.getVectorSchemaRoot().getSchema().getFields());
       int rowcount = 0;
       while (reader.loadNextBatch()) {
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("filter_id_lower_than_20")
-                .toString()
-                .equals("[true, true, true, false, false]"));
+        final ValueIterableVector<Boolean> booleanVector =
+            (ValueIterableVector<Boolean>) reader.getVectorSchemaRoot().getVector("filter_id_lower_than_20");
+        assertThat(booleanVector.getValueIterable(),
+            IsIterableContainingInOrder.contains(true, true, true, false, false));
         rowcount += reader.getVectorSchemaRoot().getRowCount();
       }
       assertEquals(5, rowcount);
@@ -617,18 +615,15 @@ public void testRunExtendedExpressionsProjectAndFilter() throws Exception {
       assertEquals(schema.getFields(), reader.getVectorSchemaRoot().getSchema().getFields());
       int rowcount = 0;
       while (reader.loadNextBatch()) {
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("add_two_to_column_a")
-                .toString()
-                .equals("[21, 3, 13]"));
-        assertTrue(
-            reader
-                .getVectorSchemaRoot()
-                .getVector("concat_column_a_and_b")
-                .toString()
-                .equals("[value_19 - value_19, value_1 - value_1, value_11 - value_11]"));
+        final ValueIterableVector<Integer> sumVector =
+            (ValueIterableVector<Integer>) reader.getVectorSchemaRoot().getVector("add_two_to_column_a");
+        assertThat(sumVector.getValueIterable(), IsIterableContainingInOrder.contains(21, 3, 13));
+        final ValueIterableVector<Text> nameVector =
+            (ValueIterableVector<Text>) reader.getVectorSchemaRoot().getVector("conccat_column_a_and_b");
+        assertThat(nameVector.getValueIterable(),
+            IsIterableContainingInOrder.contains(
+                new Text("value_19 - value_19"), new Text("value_1 - value_1"),
+                new Text("value_11 - value_11")));
         rowcount += reader.getVectorSchemaRoot().getRowCount();
       }
       assertEquals(3, rowcount);

java/vector/src/main/codegen/templates/DenseUnionVector.java

@@ -23,6 +23,7 @@
 import org.apache.arrow.vector.BaseValueVector;
 import org.apache.arrow.vector.BitVectorHelper;
 import org.apache.arrow.vector.FieldVector;
+import org.apache.arrow.vector.ValueIterableVector;
 import org.apache.arrow.vector.ValueVector;
 import org.apache.arrow.vector.complex.AbstractStructVector;
 import org.apache.arrow.vector.complex.ListVector;
@@ -62,6 +63,7 @@
 import org.apache.arrow.vector.util.CallBack;
 import org.apache.arrow.vector.ipc.message.ArrowFieldNode;
 import org.apache.arrow.vector.BaseValueVector;
+import org.apache.arrow.vector.ValueIterableVector;
 import org.apache.arrow.vector.util.OversizedAllocationException;
 import org.apache.arrow.util.Preconditions;
 
@@ -84,7 +86,7 @@
  * each time the vector is accessed.
  * Source code generated using FreeMarker template ${.template_name}
  */
-public class DenseUnionVector extends AbstractContainerVector implements FieldVector {
+public class DenseUnionVector extends AbstractContainerVector implements FieldVector, ValueIterableVector<Object> {
   int valueCount;
 
   NonNullableStructVector internalStruct;

java/vector/src/main/java/org/apache/arrow/vector/BigIntVector.java

@@ -33,7 +33,7 @@
  * BigIntVector implements a fixed width vector (8 bytes) of integer values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class BigIntVector extends BaseFixedWidthVector implements BaseIntVector {
+public final class BigIntVector extends BaseFixedWidthVector implements BaseIntVector, ValueIterableVector<Long> {
   public static final byte TYPE_WIDTH = 8;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/BitVector.java

@@ -38,7 +38,7 @@
  * BitVector implements a fixed width (1 bit) vector of boolean values which could be null. Each
  * value in the vector corresponds to a single bit in the underlying data stream backing the vector.
  */
-public final class BitVector extends BaseFixedWidthVector {
+public final class BitVector extends BaseFixedWidthVector implements ValueIterableVector<Boolean> {
 
   private static final int HASH_CODE_FOR_ZERO = 17;
 

java/vector/src/main/java/org/apache/arrow/vector/DateDayVector.java

@@ -33,7 +33,7 @@
  * DateDayVector implements a fixed width (4 bytes) vector of date values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class DateDayVector extends BaseFixedWidthVector {
+public final class DateDayVector extends BaseFixedWidthVector implements ValueIterableVector<Integer> {
 
   public static final byte TYPE_WIDTH = 4;
 

java/vector/src/main/java/org/apache/arrow/vector/DateMilliVector.java

@@ -35,7 +35,7 @@
  * DateMilliVector implements a fixed width vector (8 bytes) of date values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class DateMilliVector extends BaseFixedWidthVector {
+public final class DateMilliVector extends BaseFixedWidthVector implements ValueIterableVector<LocalDateTime> {
   public static final byte TYPE_WIDTH = 8;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/Decimal256Vector.java

@@ -40,7 +40,7 @@
  * null. A validity buffer (bit vector) is maintained to track which elements in the vector are
  * null.
  */
-public final class Decimal256Vector extends BaseFixedWidthVector {
+public final class Decimal256Vector extends BaseFixedWidthVector implements ValueIterableVector<BigDecimal> {
   public static final int MAX_PRECISION = 76;
   public static final byte TYPE_WIDTH = 32;
   private static final boolean LITTLE_ENDIAN = ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN;

java/vector/src/main/java/org/apache/arrow/vector/DecimalVector.java

@@ -39,7 +39,7 @@
  * DecimalVector implements a fixed width vector (16 bytes) of decimal values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class DecimalVector extends BaseFixedWidthVector {
+public final class DecimalVector extends BaseFixedWidthVector implements ValueIterableVector<BigDecimal> {
   public static final int MAX_PRECISION = 38;
   public static final byte TYPE_WIDTH = 16;
   private static final boolean LITTLE_ENDIAN = ByteOrder.nativeOrder() == ByteOrder.LITTLE_ENDIAN;

java/vector/src/main/java/org/apache/arrow/vector/DurationVector.java

@@ -38,7 +38,7 @@
  * duration values which could be null. A validity buffer (bit vector) is maintained to track which
  * elements in the vector are null.
  */
-public final class DurationVector extends BaseFixedWidthVector {
+public final class DurationVector extends BaseFixedWidthVector implements ValueIterableVector<Duration> {
   public static final byte TYPE_WIDTH = 8;
 
   private final TimeUnit unit;

java/vector/src/main/java/org/apache/arrow/vector/FixedSizeBinaryVector.java

@@ -37,7 +37,7 @@
  * FixedSizeBinaryVector implements a fixed width vector of binary values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public class FixedSizeBinaryVector extends BaseFixedWidthVector {
+public class FixedSizeBinaryVector extends BaseFixedWidthVector implements ValueIterableVector<byte[]> {
   private final int byteWidth;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/Float2Vector.java

@@ -34,7 +34,8 @@
  * Float2Vector implements a fixed width (2 bytes) vector of short values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class Float2Vector extends BaseFixedWidthVector implements FloatingPointVector {
+public final class Float2Vector extends BaseFixedWidthVector implements FloatingPointVector,
+    ValueIterableVector<Short> {
   public static final byte TYPE_WIDTH = 2;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/Float4Vector.java

@@ -33,7 +33,8 @@
  * Float4Vector implements a fixed width vector (4 bytes) of float values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class Float4Vector extends BaseFixedWidthVector implements FloatingPointVector {
+public final class Float4Vector extends BaseFixedWidthVector implements FloatingPointVector,
+    ValueIterableVector<Float> {
   public static final byte TYPE_WIDTH = 4;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/Float8Vector.java

@@ -33,7 +33,8 @@
  * Float8Vector implements a fixed width vector (8 bytes) of double values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class Float8Vector extends BaseFixedWidthVector implements FloatingPointVector {
+public final class Float8Vector extends BaseFixedWidthVector implements FloatingPointVector,
+    ValueIterableVector<Double> {
   public static final byte TYPE_WIDTH = 8;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/IntVector.java

@@ -33,7 +33,7 @@
  * IntVector implements a fixed width (4 bytes) vector of integer values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class IntVector extends BaseFixedWidthVector implements BaseIntVector {
+public final class IntVector extends BaseFixedWidthVector implements BaseIntVector, ValueIterableVector<Integer> {
   public static final byte TYPE_WIDTH = 4;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/IntervalDayVector.java

@@ -35,7 +35,7 @@
  * values which could be null. A validity buffer (bit vector) is maintained to track which elements
  * in the vector are null.
  */
-public final class IntervalDayVector extends BaseFixedWidthVector {
+public final class IntervalDayVector extends BaseFixedWidthVector implements ValueIterableVector<Duration> {
   public static final byte TYPE_WIDTH = 8;
   private static final byte MILLISECOND_OFFSET = 4;
 

java/vector/src/main/java/org/apache/arrow/vector/IntervalMonthDayNanoVector.java

@@ -39,7 +39,8 @@
  * <p>Month, day and nanoseconds are independent from one another and there is no specific limits
  * imposed on their values.
  */
-public final class IntervalMonthDayNanoVector extends BaseFixedWidthVector {
+public final class IntervalMonthDayNanoVector extends BaseFixedWidthVector
+    implements ValueIterableVector<PeriodDuration> {
   public static final byte TYPE_WIDTH = 16;
   private static final byte DAY_OFFSET = 4;
   private static final byte NANOSECOND_OFFSET = 8;

java/vector/src/main/java/org/apache/arrow/vector/IntervalYearVector.java

@@ -35,7 +35,7 @@
  * values which could be null. A validity buffer (bit vector) is maintained to track which elements
  * in the vector are null.
  */
-public final class IntervalYearVector extends BaseFixedWidthVector {
+public final class IntervalYearVector extends BaseFixedWidthVector implements ValueIterableVector<Period> {
   public static final byte TYPE_WIDTH = 4;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/LargeVarBinaryVector.java

@@ -32,7 +32,7 @@
  * NULL. A validity buffer (bit vector) is maintained to track which elements in the vector are
  * null. The size of the underlying buffer can be over 2GB.
  */
-public final class LargeVarBinaryVector extends BaseLargeVariableWidthVector {
+public final class LargeVarBinaryVector extends BaseLargeVariableWidthVector implements ValueIterableVector<byte[]> {
 
   /**
    * Instantiate a LargeVarBinaryVector. This doesn't allocate any memory for the data in vector.

java/vector/src/main/java/org/apache/arrow/vector/LargeVarCharVector.java

@@ -37,7 +37,7 @@
  *
  * <p>The offset width of this vector is 8, so the underlying buffer can be larger than 2GB.
  */
-public final class LargeVarCharVector extends BaseLargeVariableWidthVector {
+public final class LargeVarCharVector extends BaseLargeVariableWidthVector implements ValueIterableVector<Text> {
 
   /**
    * Instantiate a LargeVarCharVector. This doesn't allocate any memory for the data in vector.

java/vector/src/main/java/org/apache/arrow/vector/NullVector.java

@@ -38,7 +38,7 @@
 import org.apache.arrow.vector.util.TransferPair;
 
 /** A null type vector. */
-public class NullVector implements FieldVector {
+public class NullVector implements FieldVector, ValueIterableVector<Object> {
 
   private int valueCount;
 

java/vector/src/main/java/org/apache/arrow/vector/SmallIntVector.java

@@ -33,7 +33,7 @@
  * SmallIntVector implements a fixed width (2 bytes) vector of short values which could be null. A
  * validity buffer (bit vector) is maintained to track which elements in the vector are null.
  */
-public final class SmallIntVector extends BaseFixedWidthVector implements BaseIntVector {
+public final class SmallIntVector extends BaseFixedWidthVector implements BaseIntVector, ValueIterableVector<Short> {
   public static final byte TYPE_WIDTH = 2;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeMicroVector.java

@@ -34,7 +34,7 @@
  * which could be null. A validity buffer (bit vector) is maintained to track which elements in the
  * vector are null.
  */
-public final class TimeMicroVector extends BaseFixedWidthVector {
+public final class TimeMicroVector extends BaseFixedWidthVector implements ValueIterableVector<Long> {
   public static final byte TYPE_WIDTH = 8;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeMilliVector.java

@@ -36,7 +36,7 @@
  * which could be null. A validity buffer (bit vector) is maintained to track which elements in the
  * vector are null.
  */
-public final class TimeMilliVector extends BaseFixedWidthVector {
+public final class TimeMilliVector extends BaseFixedWidthVector implements ValueIterableVector<LocalDateTime> {
   public static final byte TYPE_WIDTH = 4;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeNanoVector.java

@@ -34,7 +34,7 @@
  * which could be null. A validity buffer (bit vector) is maintained to track which elements in the
  * vector are null.
  */
-public final class TimeNanoVector extends BaseFixedWidthVector {
+public final class TimeNanoVector extends BaseFixedWidthVector implements ValueIterableVector<Long> {
   public static final byte TYPE_WIDTH = 8;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeSecVector.java

@@ -34,7 +34,7 @@
  * could be null. A validity buffer (bit vector) is maintained to track which elements in the vector
  * are null.
  */
-public final class TimeSecVector extends BaseFixedWidthVector {
+public final class TimeSecVector extends BaseFixedWidthVector implements ValueIterableVector<Integer> {
   public static final byte TYPE_WIDTH = 4;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeStampMicroTZVector.java

@@ -35,7 +35,7 @@
  * resolution) values which could be null. A validity buffer (bit vector) is maintained to track
  * which elements in the vector are null.
  */
-public final class TimeStampMicroTZVector extends TimeStampVector {
+public final class TimeStampMicroTZVector extends TimeStampVector implements ValueIterableVector<Long> {
   private final String timeZone;
 
   /**

java/vector/src/main/java/org/apache/arrow/vector/TimeStampMicroVector.java

@@ -35,7 +35,7 @@
  * resolution) values which could be null. A validity buffer (bit vector) is maintained to track
  * which elements in the vector are null.
  */
-public final class TimeStampMicroVector extends TimeStampVector {
+public final class TimeStampMicroVector extends TimeStampVector implements ValueIterableVector<LocalDateTime> {
 
   /**
    * Instantiate a TimeStampMicroVector. This doesn't allocate any memory for the data in vector.

java/vector/src/main/java/org/apache/arrow/vector/TimeStampMilliTZVector.java

@@ -35,7 +35,7 @@
  * resolution) values which could be null. A validity buffer (bit vector) is maintained to track
  * which elements in the vector are null.
  */
-public final class TimeStampMilliTZVector extends TimeStampVector {
+public final class TimeStampMilliTZVector extends TimeStampVector implements ValueIterableVector<Long> {
   private final String timeZone;
 
   /**