ModSQL
Class LiteralTable

java.lang.Object
  |
  +--ModSQL.LiteralTable

All Implemented Interfaces:

Table

class LiteralTable

extends Object

implements Table

A literal table is a list of rows consisting of RowConstructor or Function objects.

Author:

chris.studholme@utoronto.ca

Field Summary

private int[]	column_types Type of each column in table.
private int	current_row Index of current row (-1 for before first).
private Object[]	current_value Value of current row (null for before first or after last).
private int	ncolumns Number of columns in table.
private Function[]	rows Array of rows after optimize().
private ArrayList	rows_array Array of rows before optimize() has been called.

Constructor Summary

LiteralTable()
Constructor.

Method Summary

void	addRow(Function row) Add a row to the table.
void	beforeFirst() Reset the table to before the first row.
int	getColumnCount() Returns the number of columns in the table.
String	getColumnName(int column) Get the name of a column.
int	getMaxResultSize(int column) Return the maximum number of characters String values in the specified column will have.
Object	getObject(int column) Get the value of a column in the current row as a Java object.
Object[]	getRow() Get the current row as an array of Objects.
long	getRowCount() Return number of rows.
int	getSQLType(int column) Return the SQL type of the specified column.
boolean	isConstant() Determine if this table is constant.
boolean	next() The table is initially positioned before its first row; the first call to next makes the first row the current row; the second call makes the second row the current row, etc.
void	optimize() Prepare the table for use.
void	registerWith(Object o) This method will pass the object on to all Function objects contained within.
String	toString() String description of table in the form "(row1,row2,...)".
String	toString(boolean with_brackets) Human readable description of table.

Methods inherited from class java.lang.Object

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

Field Detail

rows_array

private ArrayList rows_array

Array of rows before optimize() has been called.

rows

private Function[] rows

Array of rows after optimize().

column_types

private int[] column_types

Type of each column in table.

ncolumns

private int ncolumns

Number of columns in table.

current_row

private int current_row

Index of current row (-1 for before first).

current_value

private Object[] current_value

Value of current row (null for before first or after last).

Constructor Detail

LiteralTable

public LiteralTable()

Constructor.

Method Detail

addRow

public void addRow(Function row)
            throws SQLException

Add a row to the table. All rows of the table must have the same number of columns. If row is not of type RowConstructor, it is assumed to have exactly one column.

This method can only be called before optimize().

Parameters:

row - either a Function or RowConstructor

Throws:

SQLException - if an error occurs

registerWith

public void registerWith(Object o)
                  throws SQLException

This method will pass the object on to all Function objects contained within.

Specified by:

registerWith in interface Table

Parameters:

o - object to register with

Throws:

SQLException - if an error occurs

optimize

public void optimize()
              throws SQLException

Prepare the table for use. This method will call optimize() for each row, determine the types of each column, verify that the rows are compatible in type, and fix the rows array.

Specified by:

optimize in interface Table

Throws:

SQLException - if an error occurs

toString

public String toString(boolean with_brackets)

Human readable description of table. There are two styles here:

• "(row1,row2,...)"
• "VALUES row1,row2,..."

Specified by:

toString in interface Table

Parameters:

with_brackets - indicates whether the expression is bracketed

Returns:

human readable description of table

toString

public String toString()

String description of table in the form "(row1,row2,...)".

Overrides:

toString in class Object

Returns:

human readable description of table

isConstant

public boolean isConstant()
                   throws SQLException

Determine if this table is constant.

This method can only be called after optimize().

Specified by:

isConstant in interface Table

Returns:

true if all rows are constant

Throws:

SQLException - if an error occurs

getColumnCount

public int getColumnCount()

Returns the number of columns in the table. This value will be greater than zero.

This method can only be called after optimize().

Specified by:

getColumnCount in interface Table

Returns:

number of columns in table

getRowCount

public long getRowCount()

Return number of rows.

This method can only be called after optimize().

Specified by:

getRowCount in interface Table

Returns:

number of rows

getColumnName

public String getColumnName(int column)

Get the name of a column. This method always returns null since literal tables do not have named columns.

Specified by:

getColumnName in interface Table

Parameters:

column - column number (starting from zero)

Returns:

name of column (or null if column has no name)

getSQLType

public int getSQLType(int column)

Return the SQL type of the specified column.

Specified by:

getSQLType in interface Table

Parameters:

column - column number (starting from zero)

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize(int column)
                     throws SQLException

Return the maximum number of characters String values in the specified column will have. If the column is not of String type or if the maximum length is not known, -1 should be returned.

Specified by:

getMaxResultSize in interface Table

Parameters:

column - column number (starting from zero)

Returns:

maximum size of String returned or -1 if unknown

Throws:

SQLException - if an error occurs

beforeFirst

public void beforeFirst()

Reset the table to before the first row. After a call to this method, next() will advance to the first row in the table.

Specified by:

beforeFirst in interface Table

Following copied from interface: ModSQL.Table

Throws:

SQLException - if an error occurs

next

public boolean next()

The table is initially positioned before its first row; the first call to next makes the first row the current row; the second call makes the second row the current row, etc.

Specified by:

next in interface Table

Returns:

true if the new current row is valid; false if there are no more rows

getRow

public Object[] getRow()
                throws SQLException,
                       EndOfTable

Get the current row as an array of Objects.

Specified by:

getRow in interface Table

Returns:

array of objects or null if current row is not valid

Throws:

SQLException - if an error occurs

EndOfTable - if thrown when evaluating the row

getObject

public Object getObject(int column)
                 throws SQLException,
                        EndOfTable

Get the value of a column in the current row as a Java object. This method will throw an exception if the current row is not valid.

Specified by:

getObject in interface Table

Parameters:

column - column number (starting from zero)

Returns:

an Object holding the column value

Throws:

SQLException - if an error occurs

EndOfTable - if thrown when evaluating the row