Package org.h2.mvstore.db

Class NullValueDataType

  • All Implemented Interfaces:
    java.util.Comparator<Value>, DataType<Value>
    public final class NullValueDataType
extends java.lang.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.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private NullValueDataType()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int binarySearch​(Value key, java.lang.Object storage, int size, int initialGuess)
      Perform binary search for the key within the storage
      int compare​(Value a, Value b)
      Compare two keys.
      Value[] createStorage​(int size)
      Create storage object of array type to hold values
      int getMemory​(Value obj)
      Calculates the amount of used memory in bytes.
      boolean isMemoryEstimationAllowed()
      Whether memory estimation based on previously seen values is allowed/desirable
      Value read​(java.nio.ByteBuffer buff)
      Read an object.
      void read​(java.nio.ByteBuffer buff, java.lang.Object storage, int len)
      Read a list of objects.
      void write​(WriteBuffer buff, java.lang.Object storage, int len)
      Write a list of objects.
      void write​(WriteBuffer buff, Value obj)
      Write an object.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

      • Methods inherited from interface java.util.Comparator

        equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

    • Field Detail

    • Constructor Detail

      • NullValueDataType

        private NullValueDataType()

    • Method Detail

      • compare

        public int compare​(Value a,
                   Value b)
        Description copied from interface: DataType
        Compare two keys.
        Specified by:
        compare in interface java.util.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,
                        java.lang.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,
                  java.lang.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​(java.nio.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​(java.nio.ByteBuffer buff,
                 java.lang.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