org.apache.derby.impl.sql.execute

Class IndexColumnOrder

java.lang.Object

org.apache.derby.impl.sql.execute.IndexColumnOrder

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, Formatable, TypedFormat, ColumnOrdering

public class IndexColumnOrder
extends java.lang.Object
implements ColumnOrdering, Formatable

Basic implementation of ColumnOrdering. Not sure what to tell callers about 0-based versus 1-based numbering. Assume 0-based for now.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
IndexColumnOrder() Niladic constructor for formatable
IndexColumnOrder(int colNum)
IndexColumnOrder(int colNum, boolean ascending)
IndexColumnOrder(int colNum, boolean ascending, boolean nullsLow) constructor used by the ORDER BY clause.

Method Summary

Modifier and Type	Method and Description
int	getColumnId()
boolean	getIsAscending()
boolean	getIsNullsOrderedLow() Indicate whether NULL values should be ordered below non-NULL.
int	getTypeFormatId() Get the formatID which corresponds to this class.
void	readExternal(java.io.ObjectInput in) Read this object from a stream of stored objects.
java.lang.String	toString()
void	writeExternal(java.io.ObjectOutput out) Write this object out

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

IndexColumnOrder

public IndexColumnOrder()

Niladic constructor for formatable

IndexColumnOrder

public IndexColumnOrder(int colNum)

IndexColumnOrder

public IndexColumnOrder(int colNum,
                        boolean ascending)

IndexColumnOrder

public IndexColumnOrder(int colNum,
                        boolean ascending,
                        boolean nullsLow)

constructor used by the ORDER BY clause. This version of the constructor is used by the compiler when it processes an ORDER BY clause in a SQL statement. For such statements, the user gets to control whether NULL values are ordered as lower than all non-NULL values, or higher than all non-NULL values.

Parameters:

colNum - number of this column

ascending - whether the ORDER BY is ascendeing or descending

nullsLow - whether nulls should be ordered low

Method Detail

getColumnId

public int getColumnId()

Specified by:

getColumnId in interface ColumnOrdering

getIsAscending

public boolean getIsAscending()

Specified by:

getIsAscending in interface ColumnOrdering

getIsNullsOrderedLow

public boolean getIsNullsOrderedLow()

Indicate whether NULL values should be ordered below non-NULL. This function returns TRUE if the user has specified, via the clause in the ORDER BY clause, that NULL values of this column should sort lower than non-NULL values.

Specified by:

getIsNullsOrderedLow in interface ColumnOrdering

Returns:

whether nulls should sort low

writeExternal

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

Write this object out

Specified by:

writeExternal in interface java.io.Externalizable

Parameters:

out - write bytes here

Throws:

java.io.IOException - thrown on error

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Read this object from a stream of stored objects.

Specified by:

readExternal in interface java.io.Externalizable

Parameters:

in - read this.

Throws:

java.io.IOException - thrown on error

java.lang.ClassNotFoundException - thrown on error

getTypeFormatId

public int getTypeFormatId()

Get the formatID which corresponds to this class.

Specified by:

getTypeFormatId in interface TypedFormat

Returns:

the formatID of this class

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object