ARROW-5198: [JAVA] add hasNull flag to Vectors

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

@@ -49,6 +49,7 @@ public abstract class BaseFixedWidthVector extends BaseValueVector
   protected ArrowBuf validityBuffer;
   protected ArrowBuf valueBuffer;
   protected int valueCount;
+  protected boolean hasNull;
 
   public BaseFixedWidthVector(final String name, final BufferAllocator allocator,
                                       FieldType fieldType, final int typeWidth) {
@@ -60,6 +61,7 @@ public BaseFixedWidthVector(final String name, final BufferAllocator allocator,
     validityBuffer = allocator.getEmpty();
     valueBuffer = allocator.getEmpty();
     lastValueCapacity = INITIAL_VALUE_ALLOCATION;
+    hasNull = true;
   }
 
 
@@ -558,6 +560,7 @@ public void transferTo(BaseFixedWidthVector target) {
     target.validityBuffer = validityBuffer.transferOwnership(target.allocator).buffer;
     target.valueBuffer = valueBuffer.transferOwnership(target.allocator).buffer;
     target.valueCount = valueCount;
+    target.hasNull = hasNull;
     clear();
   }
 
@@ -600,6 +603,7 @@ private void splitAndTransferValidityBuffer(int startIndex, int length,
     int offset = startIndex % 8;
 
     if (length > 0) {
+      target.hasNull = hasNull;
       if (offset == 0) {
         /* slice */
         if (target.validityBuffer != null) {
@@ -665,7 +669,42 @@ private void splitAndTransferValidityBuffer(int startIndex, int length,
    */
   @Override
   public int getNullCount() {
-    return BitVectorHelper.getNullCount(validityBuffer, valueCount);
+    if (hasNull) {
+      return BitVectorHelper.getNullCount(validityBuffer, valueCount);
+    }
+    return 0;
+  }
+
+  /**
+   * Set the element at the given index to null.
+   *
+   * @param index position of element
+   */
+  public void setNull(int index) {
+    handleSafe(index);
+    setNullUnsafe(index);
+  }
+
+
+  /**
+   * Set the element at the given index to null without boundary check.
+   *
+   * @param index position of element
+   */
+  public void setNullUnsafe(int index) {
+    // not really needed to set the bit to 0 as long as
+    // the buffer always starts from 0.
+    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+    setHasNull(true);
+  }
+
+  /**
+   * Set the flag to indicate if the vector has null.
+   *
+   * @param hasNull flag to indicate if the vector has null
+   */
+  public void setHasNull(boolean hasNull) {
+    this.hasNull = hasNull;
   }
 
   /**
@@ -756,6 +795,10 @@ public boolean isNull(int index) {
    * @return 1 if element at given index is not null, 0 otherwise
    */
   public int isSet(int index) {
+    if (!hasNull) {
+      return 1;
+    }
+
     final int byteIndex = index >> 3;
     final byte b = validityBuffer.getByte(byteIndex);
     final int bitIndex = index & 7;

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

@@ -50,6 +50,7 @@ public abstract class BaseVariableWidthVector extends BaseValueVector
   protected int valueCount;
   protected int lastSet;
   protected final Field field;
+  protected boolean hasNull;
 
   public BaseVariableWidthVector(final String name, final BufferAllocator allocator,
                                          FieldType fieldType) {
@@ -63,6 +64,7 @@ public BaseVariableWidthVector(final String name, final BufferAllocator allocato
     offsetBuffer = allocator.getEmpty();
     validityBuffer = allocator.getEmpty();
     valueBuffer = allocator.getEmpty();
+    hasNull = true;
   }
 
   /* TODO:
@@ -672,6 +674,7 @@ public TransferPair getTransferPair(BufferAllocator allocator) {
   public void transferTo(BaseVariableWidthVector target) {
     compareTypes(target, "transferTo");
     target.clear();
+    target.hasNull = hasNull;
     target.validityBuffer = validityBuffer.transferOwnership(target.allocator).buffer;
     target.valueBuffer = valueBuffer.transferOwnership(target.allocator).buffer;
     target.offsetBuffer = offsetBuffer.transferOwnership(target.allocator).buffer;
@@ -733,6 +736,7 @@ private void splitAndTransferValidityBuffer(int startIndex, int length,
     int offset = startIndex % 8;
 
     if (length > 0) {
+      target.hasNull = hasNull;
       if (offset == 0) {
         // slice
         if (target.validityBuffer != null) {
@@ -794,7 +798,10 @@ private void splitAndTransferValidityBuffer(int startIndex, int length,
    * @return the number of null elements.
    */
   public int getNullCount() {
-    return BitVectorHelper.getNullCount(validityBuffer, valueCount);
+    if (hasNull) {
+      return BitVectorHelper.getNullCount(validityBuffer, valueCount);
+    }
+    return 0;
   }
 
   /**
@@ -818,13 +825,26 @@ public boolean isNull(int index) {
     return (isSet(index) == 0);
   }
 
+  /**
+   * Set the flag to indicate if the vector has null.
+   *
+   * @param hasNull flag to indicate if the vector has null
+   */
+  public void setHasNull(boolean hasNull) {
+    this.hasNull = hasNull;
+  }
+
   /**
    * Same as {@link #isNull(int)}.
    *
    * @param index  position of element
    * @return 1 if element at given index is not null, 0 otherwise
    */
   public int isSet(int index) {
+    if (!hasNull) {
+      return 1;
+    }
+
     final int byteIndex = index >> 3;
     final byte b = validityBuffer.getByte(byteIndex);
     final int bitIndex = index & 7;

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

@@ -197,7 +197,7 @@ public void set(int index, NullableBigIntHolder holder) throws IllegalArgumentEx
       BitVectorHelper.setValidityBitToOne(validityBuffer, index);
       setValue(index, holder.value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 
@@ -251,18 +251,6 @@ public void setSafe(int index, BigIntHolder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -274,7 +262,7 @@ public void set(int index, int isSet, long value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -144,6 +144,7 @@ public int getBufferSize() {
   public void splitAndTransferTo(int startIndex, int length, BaseFixedWidthVector target) {
     compareTypes(target, "splitAndTransferTo");
     target.clear();
+    target.hasNull = hasNull;
     target.validityBuffer = splitAndTransferBuffer(startIndex, length, target,
             validityBuffer, target.validityBuffer);
     target.valueBuffer = splitAndTransferBuffer(startIndex, length, target,
@@ -401,18 +402,6 @@ public void setSafe(int index, BitHolder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -425,7 +414,7 @@ public void set(int index, int isSet, int value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -252,18 +252,6 @@ public void setSafe(int index, DateDayHolder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -276,7 +264,7 @@ public void set(int index, int isSet, int value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -203,6 +203,7 @@ public void set(int index, NullableDateMilliHolder holder) throws IllegalArgumen
       setValue(index, holder.value);
     } else {
       BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setHasNull(true);
     }
   }
 
@@ -256,18 +257,6 @@ public void setSafe(int index, DateMilliHolder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -280,7 +269,7 @@ public void set(int index, int isSet, long value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -438,18 +438,6 @@ public void setSafe(int index, DecimalHolder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -463,7 +451,7 @@ public void set(int index, int isSet, int start, ArrowBuf buffer) {
     if (isSet > 0) {
       set(index, start, buffer);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -300,7 +300,7 @@ public void set(int index, NullableFixedSizeBinaryHolder holder) {
     } else if (holder.isSet > 0) {
       set(index, holder.buffer);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 
@@ -317,11 +317,6 @@ public void setSafe(int index, NullableFixedSizeBinaryHolder holder) {
     set(index, holder);
   }
 
-  public void setNull(int index) {
-    handleSafe(index);
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Given a data buffer, get the value stored at a particular position
    * in the vector.

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

@@ -253,18 +253,6 @@ public void setSafe(int index, Float4Holder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -277,7 +265,7 @@ public void set(int index, int isSet, float value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }
 

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

@@ -253,18 +253,6 @@ public void setSafe(int index, Float8Holder holder) {
     set(index, holder);
   }
 
-  /**
-   * Set the element at the given index to null.
-   *
-   * @param index   position of element
-   */
-  public void setNull(int index) {
-    handleSafe(index);
-    // not really needed to set the bit to 0 as long as
-    // the buffer always starts from 0.
-    BitVectorHelper.setValidityBit(validityBuffer, index, 0);
-  }
-
   /**
    * Store the given value at a particular position in the vector. isSet indicates
    * whether the value is NULL or not.
@@ -277,7 +265,7 @@ public void set(int index, int isSet, double value) {
     if (isSet > 0) {
       set(index, value);
     } else {
-      BitVectorHelper.setValidityBit(validityBuffer, index, 0);
+      setNullUnsafe(index);
     }
   }