Class GenericConglomerate

java.lang.Object
org.apache.derby.iapi.types.DataType
org.apache.derby.impl.store.access.conglomerate.GenericConglomerate
All Implemented Interfaces:
Externalizable, Serializable, Comparable, Formatable, Storable, TypedFormat, Conglomerate, DataValueDescriptor, Orderable
Direct Known Subclasses:
BTree, Heap

public abstract class GenericConglomerate extends DataType implements Conglomerate
A class that implements the methods shared across all implementations of the Conglomerate interface.
See Also:
  • Constructor Details

    • GenericConglomerate

      public GenericConglomerate()
  • Method Details

    • getLength

      public int getLength() throws StandardException
      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
      Throws:
      StandardException - On error
      See Also:
    • getString

      public String getString() throws StandardException
      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.
      Throws:
      StandardException - Thrown on error
      See Also:
    • getObject

      public Object getObject() throws StandardException
      Gets the value in the data value descriptor as a Java Object. The type of the Object will be the Java object type corresponding to the data value's SQL type. JDBC defines a mapping between Java object types and SQL types - we will allow that to be extended through user type definitions. Throws an exception if the data value is not an object (yeah, right).
      Specified by:
      getObject in interface DataValueDescriptor
      Overrides:
      getObject in class DataType
      Returns:
      The data value as an Object.
      Throws:
      StandardException - Thrown on error
      See Also:
    • 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()
      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) throws StandardException, SQLException
      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)
      Throws:
      StandardException - Thrown on error
      SQLException - Error accessing the result set
      See Also:
    • setFrom

      protected void setFrom(DataValueDescriptor theValue) throws StandardException
      Set the value of this DataValueDescriptor from another.
      Overrides:
      setFrom in class DataType
      Parameters:
      theValue - The Date value to set this DataValueDescriptor to
      Throws:
      StandardException
      See Also:
    • getTypeName

      public String getTypeName()
      Get the SQL name of the datatype
      Specified by:
      getTypeName in interface DataValueDescriptor
      Returns:
      The SQL name of the datatype
      See Also:
    • compare

      public int compare(DataValueDescriptor other) throws StandardException
      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 less 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
      See Also:
    • hasCollatedColumns

      public static boolean hasCollatedColumns(int[] collationIds)
      Tells if there are columns with collations (other than UCS BASIC) in the given list of collation ids.
      Parameters:
      collationIds - collation ids for the conglomerate columns
      Returns:
      true if a collation other than UCS BASIC was found.