ModSQL
Class Operator_Compare

java.lang.Object
  |
  +--ModSQL.AbstractFunction
        |
        +--ModSQL.Operator
              |
              +--ModSQL.Operator_Compare

All Implemented Interfaces:

Function

final class Operator_Compare

extends Operator

SQL comparison operators.

Author:

chris.studholme@utoronto.ca

Field Summary

static int	BETWEEN Comparison operator (between).
private int[]	compare_type Per column comparison type.
static int	EQU Comparison operator (equal).
static int	GT Comparison operator (greater than).
static int	GTE Comparison operator (greater or equal).
static int	LT Comparison operator (less than).
static int	LTE Comparison operator (less or equal).
private int	ncolumns Number of columns in row-constructor.
static int	NE Comparison operator (not equal).
private int	op Which operator? One of the above constants.
private Object[][]	row_value Value of the parameters.
private RowConstructor[]	rows One row per parameter (only if we have row-constructors).

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

Operator_Compare(int op)
Constructor.

Method Summary

static int	compare(Object v1, Object v2, int common_type) Compare two objects by converting to a common type.
static boolean	equal(Object v1, Object v2, int common_type) Check if two objects are equal by converting to a common type.
Object	evaluate(boolean aggregate) Evaluate parameters and compare.
Object	evaluate(int match_op, Object match_value) Evaluate parameters and compare.
String	functionName() Returns the name of this function for use by toString() method.
int	getMaxResultSize() Returns -1 as this operator will never return String objects.
int	getSQLType() Returns Types.BIT.
void	optimize() Prepare the function for use.
boolean	test(Object v1, Object v2)
static boolean	test(Object v1, Object v2, int op, int compare_type) Compare two objects according to op.
boolean	test(Object v1, Object v2, Object v3)
static boolean	test(Object v1, Object v2, Object v3, int compare_type)
static Boolean	testRow(Object[] r1, Object[] r2, int op, int[] compare_type) Compare two rows according to op and using compare_type array.
static Boolean	testRowInequality(Object[] r1, Object[] r2, int op, int[] compare_type) Compare two rows according to op (inequalities only) and using compare_type array.

Methods inherited from class ModSQL.Operator

addAllParameters, addAllParametersNegate, addAllParametersNot, removeDoubleNegation, removeDoubleNot

Methods inherited from class ModSQL.AbstractFunction

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

Methods inherited from class java.lang.Object

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

Field Detail

EQU

public static final int EQU

Comparison operator (equal).

GT

public static final int GT

Comparison operator (greater than).

GTE

public static final int GTE

Comparison operator (greater or equal).

LT

public static final int LT

Comparison operator (less than).

LTE

public static final int LTE

Comparison operator (less or equal).

NE

public static final int NE

Comparison operator (not equal).

BETWEEN

public static final int BETWEEN

Comparison operator (between).

op

private int op

Which operator? One of the above constants.

compare_type

private int[] compare_type

Per column comparison type.

rows

private RowConstructor[] rows

One row per parameter (only if we have row-constructors).

row_value

private Object[][] row_value

Value of the parameters.

ncolumns

private int ncolumns

Number of columns in row-constructor.

Constructor Detail

Operator_Compare

public Operator_Compare(int op)

Constructor.

Parameters:

op - operator type

Method Detail

optimize

public void optimize()
              throws SQLException

Prepare the function for use. This method checks the parameters and figures out how the comparison will take place (what type to use).

Overrides:

optimize in class AbstractFunction

Throws:

SQLException - if the parameters are invalid

functionName

public String functionName()

Returns the name of this function for use by toString() method.

Overrides:

functionName in class AbstractFunction

Returns:

name of function

getSQLType

public int getSQLType()

Returns Types.BIT.

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize()

Returns -1 as this operator will never return String objects.

Returns:

maximum size of String returned or -1 if unknown

evaluate

public Object evaluate(boolean aggregate)
                throws SQLException,
                       EndOfTable

Evaluate parameters and compare.

Parameters:

aggregate - passed to parameters

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter

evaluate

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

Evaluate parameters and compare.

Overrides:

evaluate in class AbstractFunction

Parameters:

match_op - how the value should be matched

match_value - desired value

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter

testRow

public static Boolean testRow(Object[] r1,
                              Object[] r2,
                              int op,
                              int[] compare_type)
                       throws SQLException

Compare two rows according to op and using compare_type array.

Parameters:

r1 - left row

r2 - right row

op - comparison operation

compare_type - type to convert to for comparison

Returns:

result of comparison

Throws:

SQLException - if op is invalid or on type mismatch

testRowInequality

public static Boolean testRowInequality(Object[] r1,
                                        Object[] r2,
                                        int op,
                                        int[] compare_type)
                                 throws SQLException

Compare two rows according to op (inequalities only) and using compare_type array.

Parameters:

r1 - left row

r2 - right row

op - comparison operation

compare_type - type to convert to for comparison

Returns:

result of comparison

Throws:

SQLException - if op is invalid or on type mismatch

test

public static boolean test(Object v1,
                           Object v2,
                           int op,
                           int compare_type)
                    throws SQLException

Compare two objects according to op.

Parameters:

v1 - left value

v2 - right value

op - comparison operation

compare_type - type to convert to for comparison

Returns:

result of comparison

Throws:

SQLException - if op is invalid or on type mismatch

test

public boolean test(Object v1,
                    Object v2)
             throws SQLException

test

public static boolean test(Object v1,
                           Object v2,
                           Object v3,
                           int compare_type)
                    throws SQLException

test

public boolean test(Object v1,
                    Object v2,
                    Object v3)
             throws SQLException

equal

public static boolean equal(Object v1,
                            Object v2,
                            int common_type)

Check if two objects are equal by converting to a common type.

Parameters:

v1 - left value

v2 - right value

compare_type - type to convert to for comparison

Returns:

true if the objects are equal

compare

public static int compare(Object v1,
                          Object v2,
                          int common_type)
                   throws SQLException

Compare two objects by converting to a common type.

Parameters:

v1 - left value

v2 - right value

compare_type - type to convert to for comparison

Returns:

negative if v1<v2, positive if v1>v2, 0 if equal

Throws:

SQLException - if type mismatch