Class HeapRowLocation

java.lang.Object
org.apache.derby.iapi.types.DataType
org.apache.derby.impl.store.access.heap.HeapRowLocation
All Implemented Interfaces:
Externalizable, Serializable, Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, Orderable, RefDataValue, RowLocation

public class HeapRowLocation extends DataType implements RowLocation, RefDataValue
A heap row location represents the location of a row in the heap.

It is implementad as a wrapper around a raw store record handle.

See Also:
  • Field Details

    • pageno

      private long pageno
      The HeapRowLocation simply maintains a raw store record handle.
    • recid

      private int recid
    • rh

      private RecordHandle rh
    • BASE_MEMORY_USAGE

      private static final int BASE_MEMORY_USAGE
    • RECORD_HANDLE_MEMORY_USAGE

      private static final int RECORD_HANDLE_MEMORY_USAGE
  • Constructor Details

    • HeapRowLocation

      HeapRowLocation(RecordHandle rh)
    • HeapRowLocation

      public HeapRowLocation()
    • HeapRowLocation

      private HeapRowLocation(HeapRowLocation other)
  • 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
    • 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
    • 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)
    • 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
    • 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.
    • 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.
    • recycle

      public DataValueDescriptor recycle()
      Recycle this HeapRowLocation object.
      Specified by:
      recycle in interface DataValueDescriptor
      Overrides:
      recycle in class DataType
      Returns:
      this object reset to its initial state
    • 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
    • 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.
    • compare

      public boolean compare(int op, DataValueDescriptor other, boolean orderedNulls, boolean unknownRV)
      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!)
    • compare

      public int compare(DataValueDescriptor other)
      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.
    • 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.
    • getRecordHandle

      public RecordHandle getRecordHandle(ContainerHandle ch) throws StandardException
      Throws:
      StandardException
    • setFrom

      void setFrom(RecordHandle rh)
    • 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:
      ClassNotFoundException - A class needed to read the stored form of this object could not be found.
      IOException
      See Also:
    • readExternalFromArray

      public void readExternalFromArray(ArrayInputStream in) throws IOException, ClassNotFoundException
      Description copied from class: DataType
      Read the DataValueDescriptor from the stream. The default implementation calls readExternal(), which accesses the ArrayInputStream as a generic stream. If sub-classes can implement it more efficiently by accessing the array, they should override this method.
      Specified by:
      readExternalFromArray in interface DataValueDescriptor
      Overrides:
      readExternalFromArray in class DataType
      Parameters:
      in - The array stream positioned at the beginning of the byte stream to read from.
      Throws:
      IOException - Usual error is if you try to read past limit on the stream.
      ClassNotFoundException - If a necessary class can not be found while reading the object from the stream.
      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
    • setFrom

      protected void setFrom(DataValueDescriptor theValue)
      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.
    • equals

      public boolean equals(Object ref)
      Implement value equality.
      MT - Thread safe
      Overrides:
      equals in class DataType
    • hashCode

      public int hashCode()
      Return a hashcode based on value.
      MT - thread safe
      Overrides:
      hashCode in class Object
    • toString

      public String toString()
      Overrides:
      toString in class Object