ARROW-9377: [Java] Resolve comments

java/vector/src/main/java/org/apache/arrow/vector/UInt1Vector.java

@@ -36,6 +36,16 @@
  * maintained to track which elements in the vector are null.
  */
 public final class UInt1Vector extends BaseFixedWidthVector implements BaseIntVector {
+  /**
+   * The mask to use when promoting the unsigned byte value to an integer.
+   */
+  public static final int PROMOTION_MASK = 0xFF;
+
+  /**
+   * The maximum 8-bit unsigned integer.
+   */
+  public static final byte MAX_UINT1 = (byte) 0XFF;
+
   private static final byte TYPE_WIDTH = 1;
   private final FieldReader reader;
 
@@ -83,7 +93,7 @@ public MinorType getMinorType() {
    */
   public static short getNoOverflow(final ArrowBuf buffer, final int index) {
     byte b = buffer.getByte(index * TYPE_WIDTH);
-    return (short) (0xFF & b);
+    return (short) (PROMOTION_MASK & b);
   }
 
 
@@ -315,7 +325,7 @@ public void setUnsafeWithPossibleTruncate(int index, long value) {
 
   @Override
   public long getValueAsLong(int index) {
-    return this.get(index) & 0xffL;
+    return this.get(index) & PROMOTION_MASK;
   }
 
 

java/vector/src/main/java/org/apache/arrow/vector/UInt2Vector.java

@@ -36,6 +36,12 @@
  * maintained to track which elements in the vector are null.
  */
 public final class UInt2Vector extends BaseFixedWidthVector implements BaseIntVector {
+
+  /**
+   * The maximum 16-bit unsigned integer.
+   */
+  public static final char MAX_UINT2 = (char) 0XFFFF;
+
   private static final byte TYPE_WIDTH = 2;
   private final FieldReader reader;
 

java/vector/src/main/java/org/apache/arrow/vector/UInt4Vector.java

@@ -36,6 +36,17 @@
  * maintained to track which elements in the vector are null.
  */
 public final class UInt4Vector extends BaseFixedWidthVector implements BaseIntVector {
+
+  /**
+   * The mask to use when promoting the unsigned int value to a long int.
+   */
+  public static final long PROMOTION_MASK = 0x00000000FFFFFFFFL;
+
+  /**
+   * The maximum 32-bit unsigned integer.
+   */
+  public static final int MAX_UINT4 = 0XFFFFFFFF;
+
   private static final byte TYPE_WIDTH = 4;
   private final FieldReader reader;
 
@@ -83,7 +94,7 @@ public MinorType getMinorType() {
    */
   public static long getNoOverflow(final ArrowBuf buffer, final int index) {
     long l = buffer.getInt((long) index * TYPE_WIDTH);
-    return (0x00000000FFFFFFFFL) & l;
+    return PROMOTION_MASK & l;
   }
 
   /**
@@ -286,7 +297,7 @@ public void setUnsafeWithPossibleTruncate(int index, long value) {
 
   @Override
   public long getValueAsLong(int index) {
-    return this.get(index) & 0xffffffffL;
+    return this.get(index) & PROMOTION_MASK;
   }
 
   private class TransferImpl implements TransferPair {

java/vector/src/main/java/org/apache/arrow/vector/UInt8Vector.java

@@ -38,6 +38,12 @@
  * maintained to track which elements in the vector are null.
  */
 public final class UInt8Vector extends BaseFixedWidthVector implements BaseIntVector {
+
+  /**
+   * The maximum 64-bit unsigned long integer.
+   */
+  public static final long MAX_UINT8 = 0XFFFFFFFFFFFFFFFFL;
+
   private static final byte TYPE_WIDTH = 8;
   private final FieldReader reader;
 

java/vector/src/test/java/org/apache/arrow/vector/TestDictionaryVector.java

@@ -911,7 +911,8 @@ public void testDictionaryUInt1() {
     try (VarCharVector dictionaryVector = new VarCharVector("dict vector", allocator)) {
       setVector(dictionaryVector, "0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
       Dictionary dictionary1 = new Dictionary(dictionaryVector,
-          new DictionaryEncoding(/*id=*/10L, /*ordered=*/false, /*indexType=*/ new ArrowType.Int(8, false)));
+          new DictionaryEncoding(/*id=*/10L, /*ordered=*/false,
+              /*indexType=*/new ArrowType.Int(/*bitWidth*/8, /*isSigned*/false)));
       testDictionary(dictionary1, (vector, index) -> ((UInt1Vector) vector).get(index));
     }
   }
@@ -921,7 +922,8 @@ public void testDictionaryUInt2() {
     try (VarCharVector dictionaryVector = new VarCharVector("dict vector", allocator)) {
       setVector(dictionaryVector, "0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
       Dictionary dictionary2 = new Dictionary(dictionaryVector,
-          new DictionaryEncoding(/*id=*/20L, /*ordered=*/false, /*indexType=*/ new ArrowType.Int(16, false)));
+          new DictionaryEncoding(/*id=*/20L, /*ordered=*/false,
+              /*indexType=*/new ArrowType.Int(/*indexType=*/16, /*isSigned*/false)));
       testDictionary(dictionary2, (vector, index) -> ((UInt2Vector) vector).get(index));
     }
   }
@@ -931,7 +933,8 @@ public void testDictionaryUInt4() {
     try (VarCharVector dictionaryVector = new VarCharVector("dict vector", allocator)) {
       setVector(dictionaryVector, "0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
       Dictionary dictionary4 = new Dictionary(dictionaryVector,
-          new DictionaryEncoding(/*id=*/30L, /*ordered=*/false, /*indexType=*/ new ArrowType.Int(32, false)));
+          new DictionaryEncoding(/*id=*/30L, /*ordered=*/false,
+              /*indexType=*/new ArrowType.Int(/*indexType=*/32, /*isSigned*/false)));
       testDictionary(dictionary4, (vector, index) -> ((UInt4Vector) vector).get(index));
     }
   }
@@ -941,7 +944,8 @@ public void testDictionaryUInt8() {
     try (VarCharVector dictionaryVector = new VarCharVector("dict vector", allocator)) {
       setVector(dictionaryVector, "0", "1", "2", "3", "4", "5", "6", "7", "8", "9");
       Dictionary dictionary8 = new Dictionary(dictionaryVector,
-              new DictionaryEncoding(/*id=*/40L, /*ordered=*/false, /*indexType=*/ new ArrowType.Int(64, false)));
+              new DictionaryEncoding(/*id=*/40L, /*ordered=*/false,
+                  /*indexType=*/new ArrowType.Int(/*indexType=*/64, /*isSigned*/false)));
       testDictionary(dictionary8, (vector, index) -> (int) ((UInt8Vector) vector).get(index));
     }
   }
@@ -958,7 +962,8 @@ public void testDictionaryUIntOverflow() {
       dictionaryVector.setValueCount(vecLength);
 
       Dictionary dictionary = new Dictionary(dictionaryVector,
-          new DictionaryEncoding(/*id=*/10L, /*ordered=*/false, /*indexType=*/ new ArrowType.Int(8, false)));
+          new DictionaryEncoding(/*id=*/10L, /*ordered=*/false,
+              /*indexType=*/new ArrowType.Int(/*indexType=*/8, /*isSigned*/false)));
 
       try (VarCharVector vector = new VarCharVector("vector", allocator)) {
         setVector(vector, "255");

java/vector/src/test/java/org/apache/arrow/vector/TestValueVector.java

@@ -2983,12 +2983,12 @@ public void testSetGetUInt1() {
     try (UInt1Vector vector = new UInt1Vector("vector", allocator)) {
       vector.allocateNew(2);
 
-      vector.setWithPossibleTruncate(0, 0xffL);
-      vector.setUnsafeWithPossibleTruncate(1, 0xffL);
+      vector.setWithPossibleTruncate(0, UInt1Vector.MAX_UINT1);
+      vector.setUnsafeWithPossibleTruncate(1, UInt1Vector.MAX_UINT1);
       vector.setValueCount(2);
 
-      assertEquals(255, vector.getValueAsLong(0));
-      assertEquals(255, vector.getValueAsLong(1));
+      assertEquals(UInt1Vector.MAX_UINT1 & UInt1Vector.PROMOTION_MASK, vector.getValueAsLong(0));
+      assertEquals(UInt1Vector.MAX_UINT1 & UInt1Vector.PROMOTION_MASK, vector.getValueAsLong(1));
     }
   }
 
@@ -2997,12 +2997,12 @@ public void testSetGetUInt2() {
     try (UInt2Vector vector = new UInt2Vector("vector", allocator)) {
       vector.allocateNew(2);
 
-      vector.setWithPossibleTruncate(0, 0xffffL);
-      vector.setUnsafeWithPossibleTruncate(1, 0xffffL);
+      vector.setWithPossibleTruncate(0, UInt2Vector.MAX_UINT2);
+      vector.setUnsafeWithPossibleTruncate(1, UInt2Vector.MAX_UINT2);
       vector.setValueCount(2);
 
-      assertEquals(65535, vector.getValueAsLong(0));
-      assertEquals(65535, vector.getValueAsLong(1));
+      assertEquals(UInt2Vector.MAX_UINT2, vector.getValueAsLong(0));
+      assertEquals(UInt2Vector.MAX_UINT2, vector.getValueAsLong(1));
     }
   }
 
@@ -3011,11 +3011,11 @@ public void testSetGetUInt4() {
     try (UInt4Vector vector = new UInt4Vector("vector", allocator)) {
       vector.allocateNew(2);
 
-      vector.setWithPossibleTruncate(0, 0xffffffffL);
-      vector.setUnsafeWithPossibleTruncate(1, 0xffffffffL);
+      vector.setWithPossibleTruncate(0, UInt4Vector.MAX_UINT4);
+      vector.setUnsafeWithPossibleTruncate(1, UInt4Vector.MAX_UINT4);
       vector.setValueCount(2);
 
-      long expected = (1L << 32) - 1L;
+      long expected = UInt4Vector.MAX_UINT4 & UInt4Vector.PROMOTION_MASK;
       assertEquals(expected, vector.getValueAsLong(0));
       assertEquals(expected, vector.getValueAsLong(1));
     }