Class NullValueDataType

java.lang.Object
org.h2.mvstore.db.NullValueDataType
All Implemented Interfaces:
Comparator<Value>, DataType<Value>
public final class NullValueDataType extends Object implements DataType<Value>
Dummy data type used when no value is required. This data type doesn't use any disk space and always returns SQL NULL value.

  • Field Details

    • INSTANCE

      public static final NullValueDataType INSTANCE
      Dummy data type instance.

  • Constructor Details

    • NullValueDataType

      private NullValueDataType()

  • Method Details

    • compare

      public int compare(Value a, Value b)
      Description copied from interface: DataType
      Compare two keys.
      Specified by:
      compare in interface Comparator<Value>
      Specified by:
      compare in interface DataType<Value>
      Parameters:
      a - the first key
      b - the second key
      Returns:
      -1 if the first key is smaller, 1 if larger, and 0 if equal

    • binarySearch

      public int binarySearch(Value key, Object storage, int size, int initialGuess)
      Description copied from interface: DataType
      Perform binary search for the key within the storage
      Specified by:
      binarySearch in interface DataType<Value>
      Parameters:
      key - to search for
      storage - to search within (an array of type T)
      size - number of data items in the storage
      initialGuess - for key position
      Returns:
      index of the key , if found, - index of the insertion point, if not

    • getMemory

      public int getMemory(Value obj)
      Description copied from interface: DataType
      Calculates the amount of used memory in bytes.
      Specified by:
      getMemory in interface DataType<Value>
      Parameters:
      obj - the object
      Returns:
      the used memory

    • isMemoryEstimationAllowed

      public boolean isMemoryEstimationAllowed()
      Description copied from interface: DataType
      Whether memory estimation based on previously seen values is allowed/desirable
      Specified by:
      isMemoryEstimationAllowed in interface DataType<Value>
      Returns:
      true if memory estimation is allowed

    • write

      public void write(WriteBuffer buff, Value obj)
      Description copied from interface: DataType
      Write an object.
      Specified by:
      write in interface DataType<Value>
      Parameters:
      buff - the target buffer
      obj - the value

    • write

      public void write(WriteBuffer buff, Object storage, int len)
      Description copied from interface: DataType
      Write a list of objects.
      Specified by:
      write in interface DataType<Value>
      Parameters:
      buff - the target buffer
      storage - the objects
      len - the number of objects to write

    • read

      public Value read(ByteBuffer buff)
      Description copied from interface: DataType
      Read an object.
      Specified by:
      read in interface DataType<Value>
      Parameters:
      buff - the source buffer
      Returns:
      the object

    • read

      public void read(ByteBuffer buff, Object storage, int len)
      Description copied from interface: DataType
      Read a list of objects.
      Specified by:
      read in interface DataType<Value>
      Parameters:
      buff - the target buffer
      storage - the objects
      len - the number of objects to read

    • createStorage

      public Value[] createStorage(int size)
      Description copied from interface: DataType
      Create storage object of array type to hold values
      Specified by:
      createStorage in interface DataType<Value>
      Parameters:
      size - number of values to hold
      Returns:
      storage object