xxl.relational
Class Projection

java.lang.Object
  |
  +--xxl.relational.AbstractResultSet
        |
        +--xxl.relational.Projection

public class Projection

extends AbstractResultSet

The operator for projection (without duplicate removal).
For each tuple of the given resultSet a new tuple will be computed. This technique includes e.g. renaming functionality.

Examples:

	new Projection(new String[]{"name", "birth year"}, resultSet);
	

creates a projection on the columns "name" and "birth year" as expected.

	new Projection(new String[]{"name"}, new String[]{"last name"}, resultSet);
	

realizes a column renaming. The column "name" of the given resultSet is renamed to "last name" in the output ResultSet.

More formally:
A projection is a Function with the following syntax:

	projection.invoke()
	

returns the metadata for the output ResultSet (as java.sql.ResultSetMetaData)

	projection.invoke((Object) columnName)
	

maps the given columnName to its column index and returns it (as java.lang.Integer)

	projection.invoke((Object) columnIndex, (Object) tuple)
	

computes from the given tuple the new tuple and returns the value of column columnIndex.

Field Summary

protected Function	projection
protected java.sql.ResultSet	resultSet
protected Tuple	tuple
protected boolean	wasNull

Constructor Summary

Projection(Function projection, java.sql.ResultSet resultSet)

Projection(int[] columnIndexes, int[] columnIndexesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Projection(int[] columnIndexes, java.sql.ResultSet resultSet)

Projection(int[] columnIndexesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Projection(int[] columnIndexes, java.lang.String[] columnNamesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Projection(java.lang.String[] columnNames, int[] columnIndexesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Projection(java.lang.String[] columnNames, java.sql.ResultSet resultSet)

Projection(java.lang.String[] columnNamesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Projection(java.lang.String[] columnNames, java.lang.String[] columnNamesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)

Method Summary

void	close()
protected Function	createProjection(int[] columnIndexes, int[] columnIndexesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)
protected Function	createProjection(int[] columnIndexes, java.lang.String[] columnNames, java.sql.ResultSet resultSet)
protected Function	createProjection(int[] columnIndexes, java.lang.String[] columnNamesToRename, java.lang.String[] newNames, java.sql.ResultSet resultSet)
int	findColumn(java.lang.String columnName)
byte[]	getBytes(int columnIndex)
java.sql.ResultSetMetaData	getMetaData()
java.lang.Object	getObject(int columnIndex)
boolean	next()
boolean	wasNull()

Methods inherited from class xxl.relational.AbstractResultSet

absolute, afterLast, beforeFirst, cancelRowUpdates, clearWarnings, deleteRow, first, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getBoolean, getByte, getByte, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getColumnCount, getConcurrency, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getInt, getInt, getLong, getLong, getObject, getObject, getObject, getRef, getRef, getRow, getShort, getShort, getStatement, getString, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getWarnings, insertRow, isAfterLast, isBeforeFirst, isFirst, isLast, last, moveToCurrentRow, moveToInsertRow, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setFetchDirection, setFetchSize, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateRow, updateShort, updateShort, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

resultSet

protected java.sql.ResultSet resultSet

projection

protected Function projection

tuple

protected Tuple tuple

wasNull

protected boolean wasNull

Constructor Detail

Projection

public Projection(Function projection,
                  java.sql.ResultSet resultSet)

Projection

public Projection(int[] columnIndexes,
                  java.sql.ResultSet resultSet)

Projection

public Projection(java.lang.String[] columnNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(int[] columnIndexesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(java.lang.String[] columnNamesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(int[] columnIndexes,
                  int[] columnIndexesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(int[] columnIndexes,
                  java.lang.String[] columnNamesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(java.lang.String[] columnNames,
                  int[] columnIndexesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Projection

public Projection(java.lang.String[] columnNames,
                  java.lang.String[] columnNamesToRename,
                  java.lang.String[] newNames,
                  java.sql.ResultSet resultSet)

Method Detail

createProjection

protected Function createProjection(int[] columnIndexes,
                                    int[] columnIndexesToRename,
                                    java.lang.String[] newNames,
                                    java.sql.ResultSet resultSet)
                             throws java.sql.SQLException

createProjection

protected Function createProjection(int[] columnIndexes,
                                    java.lang.String[] columnNamesToRename,
                                    java.lang.String[] newNames,
                                    java.sql.ResultSet resultSet)
                             throws java.sql.SQLException

createProjection

protected Function createProjection(int[] columnIndexes,
                                    java.lang.String[] columnNames,
                                    java.sql.ResultSet resultSet)
                             throws java.sql.SQLException

next

public boolean next()
             throws java.sql.SQLException

Overrides:

next in class AbstractResultSet

getMetaData

public java.sql.ResultSetMetaData getMetaData()
                                       throws java.sql.SQLException

Overrides:

getMetaData in class AbstractResultSet

findColumn

public int findColumn(java.lang.String columnName)
               throws java.sql.SQLException

Overrides:

findColumn in class AbstractResultSet

getObject

public java.lang.Object getObject(int columnIndex)
                           throws java.sql.SQLException

Overrides:

getObject in class AbstractResultSet

getBytes

public byte[] getBytes(int columnIndex)
                throws java.sql.SQLException

Overrides:

getBytes in class AbstractResultSet

wasNull

public boolean wasNull()
                throws java.sql.SQLException

Overrides:

wasNull in class AbstractResultSet

close

public void close()
           throws java.sql.SQLException

Overrides:

close in class AbstractResultSet