ModSQL
Class LiteralRow

java.lang.Object
  |
  +--ModSQL.AbstractFunction
        |
        +--ModSQL.LiteralRow

All Implemented Interfaces:

Function, RowConstructor

public class LiteralRow

extends AbstractFunction

implements RowConstructor

This class represents a literal row constructor. That is, a row constructor of the form '(value,...)', where each value is of type Function.

Columns are added to the row constructor using the addParameter() method.

Author:

chris.studholme@utoronto.ca

Fields inherited from class ModSQL.AbstractFunction

all_constant, constant_non_null, evaluate_order, evaluate_order_array, out_of_order, parameter_constant, parameter_value, parameters, parameters_array

Fields inherited from interface ModSQL.Function

MATCH_BEGINS, MATCH_EQU, MATCH_GT, MATCH_GTE, MATCH_LT, MATCH_LTE, MATCH_NE

Constructor Summary

LiteralRow()
Default constructor (no columns).

LiteralRow(Function first_column)
Constructor to set first column.

Method Summary

Object	evaluate(boolean aggregate) Evaluate row.
Object	evaluate(int match_op, Object match_value) Evaluate row.
Object[]	evaluateRow(boolean aggregate) Evaluate each column of the row and return the results as an array of length equal to the value returned by getColumnCount().
String	functionName() Function name is blank (empty String) for row constructors.
int	getColumnCount() Returns the number of columns the row has.
int	getMaxResultSize() Return the maximum number of characters that this function expects to return in a String object.
int	getMaxResultSize(int column) Return the maximum number of characters String values in the specified column will have.
int	getSQLType() Return the SQL type of the value that this function expects to return.
int	getSQLType(int column) Return the SQL type of the value in the specified column.
void	optimize() Prepare the row for use.
String	toString() Returns "column1" or "(column1,column2,...)".

Methods inherited from class ModSQL.AbstractFunction

addParameter, convertToSQLType, evaluateConstantParameters, evaluateOrder, evaluateParameters, evaluateParameters, getCompatableType, getObjectSQLType, getParameter, getParameterCount, isAggregate, isConstant, postfixParameters, prefixParameters, registerWith, reset

Methods inherited from class java.lang.Object

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

Methods inherited from interface ModSQL.Function

addParameter, evaluateOrder, getParameter, getParameterCount, isAggregate, isConstant, registerWith, reset

Constructor Detail

LiteralRow

public LiteralRow()

Default constructor (no columns).

LiteralRow

public LiteralRow(Function first_column)
           throws SQLException

Constructor to set first column.

Parameters:

first_column - Function representing first column

Throws:

SQLException - if an error occurs

Method Detail

optimize

public void optimize()
              throws SQLException

Prepare the row for use. A row constructor must consist of at least one column (otherwise, an exception is thrown). Furthermore, if any of the columns are constant, they are evaluated here.

Specified by:

optimize in interface Function

Overrides:

optimize in class AbstractFunction

Throws:

SQLException - if an error occurs

functionName

public String functionName()

Function name is blank (empty String) for row constructors.

Overrides:

functionName in class AbstractFunction

Following copied from class: ModSQL.AbstractFunction

Returns:

name of function

toString

public String toString()

Returns "column1" or "(column1,column2,...)".

Overrides:

toString in class AbstractFunction

Returns:

human-readable version of row constructor

getColumnCount

public int getColumnCount()

Returns the number of columns the row has. The row will always have at least one column.

This method should only be called after optimize().

Specified by:

getColumnCount in interface RowConstructor

Returns:

number of columns in row

getSQLType

public int getSQLType()
               throws SQLException

Return the SQL type of the value that this function expects to return. This version of this method can only be used if the row has exactly one column. Otherwise, an exception is thrown.

Specified by:

getSQLType in interface Function

Returns:

SQL type of data to be returned

Throws:

SQLException - if an error occurs

getSQLType

public int getSQLType(int column)
               throws SQLException

Return the SQL type of the value in the specified column.

Specified by:

getSQLType in interface RowConstructor

Parameters:

column - column number (starting from zero)

Returns:

SQL type of data to be returned

Throws:

SQLException - if an error occurs

getMaxResultSize

public int getMaxResultSize()
                     throws SQLException

Return the maximum number of characters that this function expects to return in a String object. This version of this method can only be used if the row has exactly one column. Otherwise, an exception is thrown.

Specified by:

getMaxResultSize in interface Function

Returns:

maximum size of String returned or -1 if unknown

Throws:

SQLException - if an error occurs

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 RowConstructor

Parameters:

column - column number (starting from zero)

Returns:

maximum size of String returned or -1 if unknown

Throws:

SQLException - if an error occurs

evaluate

public Object evaluate(boolean aggregate)
                throws SQLException,
                       EndOfTable

Evaluate row. This version of this method can only be used if the row has exactly one column. Otherwise, an exception is thrown.

Specified by:

evaluate in interface Function

Parameters:

aggregate - true to return final aggregate value

Returns:

result object

Throws:

SQLException - if an error occurs

EndOfTable - if thrown by a column

evaluate

public Object evaluate(int match_op,
                       Object match_value)
                throws SQLException,
                       EndOfTable

Evaluate row. This version of this method can only be used if the row has exactly one column. Otherwise, an exception is thrown.

Specified by:

evaluate in interface Function

Overrides:

evaluate in class AbstractFunction

Parameters:

match_op - how desired value is matched

match_value - value to match to

Returns:

result object

Throws:

SQLException - if an error occurs

EndOfTable - if thrown by a column

evaluateRow

public Object[] evaluateRow(boolean aggregate)
                     throws SQLException,
                            EndOfTable

Evaluate each column of the row and return the results as an array of length equal to the value returned by getColumnCount().

Specified by:

evaluateRow in interface RowConstructor

Returns:

array of objects

Throws:

SQLException - if an error occurs

EndOfTable - if thrown by a column