Package org.h2.mvstore.type

Class BasicDataType<T>

java.lang.Object
org.h2.mvstore.type.BasicDataType<T>
All Implemented Interfaces:
Comparator<T>, DataType<T>
Direct Known Subclasses:
ByteArrayDataType, IntegerDataType, LobStorageMap.BlobMeta.Type, LobStorageMap.BlobReference.Type, LongDataType, MetaType, ObjectDataType, RowDataType, RowDataType, SpatialDataType, StringDataType, ValueDataType, VersionedValueType
public abstract class BasicDataType<T> extends Object implements DataType<T>
The base class for data type implementations.

  • Constructor Details

    • BasicDataType

      public BasicDataType()

  • Method Details

    • getMemory

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

    • write

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

    • read

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

    • compare

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

    • 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<T>
      Returns:
      true if memory estimation is allowed

    • binarySearch

      public int binarySearch(T key, Object storageObj, int size, int initialGuess)
      Description copied from interface: DataType
      Perform binary search for the key within the storage
      Specified by:
      binarySearch in interface DataType<T>
      Parameters:
      key - to search for
      storageObj - 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

    • 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<T>
      Parameters:
      buff - the target buffer
      storage - the objects
      len - the number of objects to write

    • 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<T>
      Parameters:
      buff - the target buffer
      storage - the objects
      len - the number of objects to read

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in interface Comparator<T>
      Overrides:
      equals in class Object

    • cast

      protected final T[] cast(Object storage)
      Cast the storage object to an array of type T.
      Parameters:
      storage - the storage object
      Returns:
      the array