Class SQLRef

java.lang.Object
org.apache.derby.iapi.types.DataType
org.apache.derby.iapi.types.SQLRef
All Implemented Interfaces:
Externalizable, Serializable, Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, Orderable, RefDataValue

public class SQLRef extends DataType implements RefDataValue
See Also:
  • Field Details

    • value

      protected RowLocation value
    • BASE_MEMORY_USAGE

      private static final int BASE_MEMORY_USAGE
  • Constructor Details

    • SQLRef

      public SQLRef()
    • SQLRef

      public SQLRef(RowLocation rowLocation)
  • Method Details

    • estimateMemoryUsage

      public int estimateMemoryUsage()
      Description copied from interface: DataValueDescriptor
      Estimate the memory usage in bytes of the data value and the overhead of the class.
      Specified by:
      estimateMemoryUsage in interface DataValueDescriptor
      Returns:
      the estimated memory usage
    • getString

      public String getString()
      Description copied from interface: DataValueDescriptor
      Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.
      Specified by:
      getString in interface DataValueDescriptor
      Returns:
      The data value as a String.
    • getObject

      public Object getObject()
      Description copied from class: DataType
      Gets the value in the data value descriptor as a int. Throws an exception if the data value is not receivable as a int.
      Specified by:
      getObject in interface DataValueDescriptor
      Overrides:
      getObject in class DataType
      Returns:
      The data value as a int.
    • setFrom

      protected void setFrom(DataValueDescriptor theValue) throws StandardException
      Description copied from class: DataType
      Set the value of this DataValueDescriptor based on the value of the specified DataValueDescriptor.
      Overrides:
      setFrom in class DataType
      Parameters:
      theValue - The DataValueDescriptor that holds the value to which we want to set this DataValueDescriptor's value.
      Throws:
      StandardException
    • getLength

      public int getLength()
      Description copied from interface: DataValueDescriptor
      Gets the length of the data value. The meaning of this is implementation-dependent. For string types, it is the number of characters in the string. For numeric types, it is the number of bytes used to store the number. This is the actual length of this value, not the length of the type it was defined as. For example, a VARCHAR value may be shorter than the declared VARCHAR (maximum) length.
      Specified by:
      getLength in interface DataValueDescriptor
      Returns:
      The length of the data value
    • getTypeName

      public String getTypeName()
      Description copied from interface: DataValueDescriptor
      Get the SQL name of the datatype
      Specified by:
      getTypeName in interface DataValueDescriptor
      Returns:
      The SQL name of the datatype
    • getTypeFormatId

      public int getTypeFormatId()
      Return my format identifier.
      Specified by:
      getTypeFormatId in interface TypedFormat
      Returns:
      The identifier. (A UUID stuffed in an array of 16 bytes).
      See Also:
    • isNull

      public boolean isNull()
      Description copied from interface: Storable
      Return whether the value is null or not.
      Specified by:
      isNull in interface Storable
      Returns:
      true if the value is null and false otherwise.
    • writeExternal

      public void writeExternal(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Throws:
      IOException
    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Throws:
      IOException - Thrown on error reading the object
      ClassNotFoundException - Thrown if the class of the object read from the stream can't be found (not likely, since it's supposed to be SQLRef).
      See Also:
    • restoreToNull

      public void restoreToNull()
      Description copied from interface: Storable
      Restore this object to its (SQL)null value.
      Specified by:
      restoreToNull in interface Storable
      See Also:
    • compare

      public boolean compare(int op, DataValueDescriptor other, boolean orderedNulls, boolean unknownRV) throws StandardException
      Description copied from interface: DataValueDescriptor
      Compare this Orderable with a given Orderable for the purpose of qualification and sorting. The caller gets to determine how nulls should be treated - they can either be ordered values or unknown values.
      Specified by:
      compare in interface DataValueDescriptor
      Overrides:
      compare in class DataType
      Parameters:
      op - Orderable.ORDER_OP_EQUALS means do an = comparison. Orderable.ORDER_OP_LESSTHAN means compare this < other. Orderable.ORDER_OP_LESSOREQUALS means compare this <= other.
      other - The DataValueDescriptor to compare this one to.
      orderedNulls - True means to treat nulls as ordered values, that is, treat SQL null as equal to null, and less than all other values. False means to treat nulls as unknown values, that is, the result of any comparison with a null is the UNKNOWN truth value.
      unknownRV - The return value to use if the result of the comparison is the UNKNOWN truth value. In other words, if orderedNulls is false, and a null is involved in the comparison, return unknownRV. This parameter is not used orderedNulls is true.
      Returns:
      true if the comparison is true (duh!)
      Throws:
      StandardException - Thrown on error
    • compare

      public int compare(DataValueDescriptor other) throws StandardException
      Description copied from interface: DataValueDescriptor
      Compare this Orderable with a given Orderable for the purpose of index positioning. This method treats nulls as ordered values - that is, it treats SQL null as equal to null and greater than all other values.
      Specified by:
      compare in interface DataValueDescriptor
      Parameters:
      other - The Orderable to compare this one to.
      Returns:
      <0 - this Orderable is less than other. 0 - this Orderable equals other. >0 - this Orderable is greater than other. The code should not explicitly look for -1, or 1.
      Throws:
      StandardException - Thrown on error
    • cloneValue

      public DataValueDescriptor cloneValue(boolean forceMaterialization)
      Description copied from interface: DataValueDescriptor
      Clone this DataValueDescriptor. Results in a new object that has the same value as this but can be modified independently.

      Even though the objects can be modified independently regardless of the value of forceMaterialization, both the clone and the original may be dependent on the store state if forceMaterialization is set to false. An example is if you need to access the value you just read using cloneValue after the current transaction has ended, or after the source result set has been closed.

      Specified by:
      cloneValue in interface DataValueDescriptor
      Parameters:
      forceMaterialization - any streams representing the data value will be materialized if true, the data value will be kept as a stream if possible if false
      Returns:
      A clone of the DataValueDescriptor with the same initial value as this.
      See Also:
    • getNewNull

      public DataValueDescriptor getNewNull()
      Description copied from interface: DataValueDescriptor
      Get a new null value of the same type as this data value.
      Specified by:
      getNewNull in interface DataValueDescriptor
      See Also:
    • setValueFromResultSet

      public void setValueFromResultSet(ResultSet resultSet, int colNumber, boolean isNullable)
      Description copied from interface: DataValueDescriptor
      Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
      Specified by:
      setValueFromResultSet in interface DataValueDescriptor
      Parameters:
      resultSet - The specified ResultSet.
      colNumber - The 1-based column # into the resultSet.
      isNullable - Whether or not the column is nullable (No need to call wasNull() if not)
      See Also:
    • setInto

      public void setInto(PreparedStatement ps, int position)
      Description copied from interface: DataValueDescriptor
      Set this value into a PreparedStatement. This method must handle setting NULL into the PreparedStatement.
      Specified by:
      setInto in interface DataValueDescriptor
      Overrides:
      setInto in class DataType
    • setValue

      public void setValue(RowLocation rowLocation)
      Description copied from interface: RefDataValue
      Set the value of this RefDataValue.
      Specified by:
      setValue in interface RefDataValue
      Parameters:
      rowLocation - Contains the boolean value to set this RefDataValue to. Null means set this RefDataValue to null.
    • toString

      public String toString()
      Overrides:
      toString in class Object
    • hashCode

      public int hashCode()
      Adding this overload makes it possible to use SQLRefs as keys in HashMaps.
      Overrides:
      hashCode in class Object