Package org.apache.derby.iapi.types

Class SQLSmallint

  • All Implemented Interfaces:
    java.io.Externalizable, java.io.Serializable, java.lang.Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, NumberDataValue, Orderable
    public final class SQLSmallint
extends NumberDataType
    SQLSmallint satisfies the DataValueDescriptor interfaces (i.e., OrderableDataType). It implements a smallint column, e.g. for storing a column value; it can be specified when constructed to not allow nulls. Nullability cannot be changed after construction, as it affects the storage size and mechanism.

    Because OrderableDataType is a subtype of ValueColumn, SQLSmallint can play a role in either a ValueColumn/Row or a OrderableDataType/Row, interchangeably.

    We assume the store has a flag for nullness of the value, and simply return a 0-length array for the stored form when the value is null.

    PERFORMANCE: There are likely alot of performance improvements possible for this implementation -- it new's Short more than it probably wants to.

    See Also:
    Serialized Form

    • Field Detail

      • BASE_MEMORY_USAGE

        private static final int BASE_MEMORY_USAGE

      • value

        private short value

      • isnull

        private boolean isnull

    • Constructor Detail

      • SQLSmallint

        public SQLSmallint()
        No-arg constructor, required by Formattable. // This constructor also gets used when we are // allocating space for a short.

      • SQLSmallint

        public SQLSmallint​(short val)

      • SQLSmallint

        private SQLSmallint​(short val,
                    boolean isnull)

      • SQLSmallint

        public SQLSmallint​(java.lang.Short obj)

    • Method Detail

      • getString

        public java.lang.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.
        Returns:
        The data value as a String.
        See Also:
        DataValueDescriptor.getString()

      • 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.
        Returns:
        The length of the data value
        See Also:
        DataValueDescriptor.getLength()

      • getTypeName

        public java.lang.String getTypeName()
        Description copied from interface: DataValueDescriptor
        Get the SQL name of the datatype
        Returns:
        The SQL name of the datatype

      • getTypeFormatId

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

      • isNull

        public boolean isNull()
        always false for non-nullable columns
        Returns:
        true if the value is null and false otherwise.
        See Also:
        Storable.isNull()

      • writeExternal

        public void writeExternal​(java.io.ObjectOutput out)
                   throws java.io.IOException
        Throws:
        java.io.IOException

      • readExternal

        public void readExternal​(java.io.ObjectInput in)
                  throws java.io.IOException
        Throws:
        java.io.IOException
        See Also:
        Externalizable.readExternal(java.io.ObjectInput)

      • restoreToNull

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

      • 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.

        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:
        DataValueDescriptor.cloneValue(boolean)

      • setValueFromResultSet

        public void setValueFromResultSet​(java.sql.ResultSet resultSet,
                                  int colNumber,
                                  boolean isNullable)
                           throws java.sql.SQLException
        Description copied from interface: DataValueDescriptor
        Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
        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:
        java.sql.SQLException - Thrown on error
        See Also:
        DataValueDescriptor.setValueFromResultSet(java.sql.ResultSet, int, boolean)

      • setInto

        public final void setInto​(java.sql.PreparedStatement ps,
                          int position)
                   throws java.sql.SQLException
        Set the value into a PreparedStatement.
        Specified by:
        setInto in interface DataValueDescriptor
        Overrides:
        setInto in class DataType
        Throws:
        java.sql.SQLException - Error setting value in PreparedStatement

      • setInto

        public final void setInto​(java.sql.ResultSet rs,
                          int position)
                   throws java.sql.SQLException,
                          StandardException
        Set this value into a ResultSet for a subsequent ResultSet.insertRow or ResultSet.updateRow. This method will only be called for non-null values.
        Specified by:
        setInto in interface DataValueDescriptor
        Overrides:
        setInto in class DataType
        Throws:
        java.sql.SQLException - thrown by the ResultSet object
        StandardException - thrown by me accessing my value.

      • setValue

        public void setValue​(java.lang.String theValue)
              throws StandardException
        Description copied from class: DataType
        Set the value of this DataValueDescriptor. At DataType level just throws an error lower classes will override
        Specified by:
        setValue in interface DataValueDescriptor
        Overrides:
        setValue in class DataType
        Parameters:
        theValue - The BigDecimal value to set this DataValueDescriptor to
        Throws:
        StandardException - thrown if string not accepted

      • setValue

        public void setValue​(short theValue)
        Description copied from class: NumberDataType
        Common code to handle converting a short to this value by using the int to this value conversion. Simply calls setValue(int).
        Specified by:
        setValue in interface DataValueDescriptor
        Overrides:
        setValue in class NumberDataType
        Parameters:
        theValue - The value to set this DataValueDescriptor to

      • setValue

        public void setValue​(byte theValue)
        Description copied from class: NumberDataType
        Common code to handle converting a byte to this value by using the int to this value conversion. Simply calls setValue(int).
        Specified by:
        setValue in interface DataValueDescriptor
        Overrides:
        setValue in class NumberDataType
        Parameters:
        theValue - The value to set this DataValueDescriptor to

      • setValue

        public void setValue​(int theValue)
              throws StandardException
        Description copied from class: DataType
        Set the value of this DataValueDescriptor to the given int value At DataType level just throws an error lower classes will override
        Specified by:
        setValue in interface DataValueDescriptor
        Overrides:
        setValue in class DataType
        Parameters:
        theValue - The value to set this DataValueDescriptor to
        Throws:
        StandardException - if outsideRangeForSmallint

      • setValue

        public void setValue​(long theValue)
              throws StandardException
        Description copied from class: DataType
        Set the value of this DataValueDescriptor to the given long value At DataType level just throws an error lower classes will override
        Specified by:
        setValue in interface DataValueDescriptor
        Overrides:
        setValue in class DataType
        Parameters:
        theValue - The value to set this DataValueDescriptor to
        Throws:
        StandardException - if outsideRangeForSmallint

      • 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

      • typePrecedence

        public int typePrecedence()
        Description copied from class: DataType
        Each built-in type in JSQL has a precedence. This precedence determines how to do type promotion when using binary operators. For example, float has a higher precedence than int, so when adding an int to a float, the result type is float. The precedence for some types is arbitrary. For example, it doesn't matter what the precedence of the boolean type is, since it can't be mixed with other types. But the precedence for the number types is critical. The SQL standard requires that exact numeric types be promoted to approximate numeric when one operator uses both. Also, the precedence is arranged so that one will not lose precision when promoting a type.
        Specified by:
        typePrecedence in interface DataValueDescriptor
        Overrides:
        typePrecedence in class DataType
        Returns:
        The precedence of this type.
        See Also:
        DataValueDescriptor.typePrecedence()

      • times

        public NumberDataValue times​(NumberDataValue left,
                             NumberDataValue right,
                             NumberDataValue result)
                      throws StandardException
        This method implements the * operator for "smallint * smallint".
        Parameters:
        left - The first value to be multiplied
        right - The second value to be multiplied
        result - The result of a previous call to this method, null if not called yet
        Returns:
        A SQLSmallint containing the result of the multiplication
        Throws:
        StandardException - Thrown on error

      • minus

        public NumberDataValue minus​(NumberDataValue result)
                      throws StandardException
        This method implements the unary minus operator for smallint.
        Parameters:
        result - The result of a previous call to this method, null if not called yet
        Returns:
        A SQLSmalllint containing the result of the division
        Throws:
        StandardException - Thrown on error

      • isNegative

        protected boolean isNegative()
        This method implements the isNegative method.
        Specified by:
        isNegative in class NumberDataType
        Returns:
        A boolean. If this.value is negative, return true. For positive values or null, return false.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class java.lang.Object

      • 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.
        Returns:
        the estimated memory usage