org.exolab.jms.selector
Class DefaultExpressionFactory

java.lang.Object
  |
  +--org.exolab.jms.selector.DefaultExpressionFactory

All Implemented Interfaces:

ExpressionFactory

public final class DefaultExpressionFactory

extends java.lang.Object

implements ExpressionFactory

Default implementation of ExpressionFactory

Version:

$Revision: 1.4 $ $Date: 2003/08/09 15:49:50 $

Author:

Tim Anderson

See Also:

ExpressionFactory, SelectorTokenTypes

Constructor Summary

DefaultExpressionFactory()

Method Summary

Expression	between(Expression num1, Expression num2, Expression num3) Create a 'between' expression that returns the result of: num1 >= num2 and num1 <= num3 when evaluated
Expression	binaryOperator(int operator, Expression left, Expression right) Create a binary operator expression
Expression	identifier(java.lang.String name) Create an identifier expression
Expression	in(Expression identifier, java.util.HashSet set) Create an 'in' expression
Expression	isNull(Expression identifier) Create an 'is null' expression
Expression	like(Expression identifier, java.lang.String pattern, java.lang.String escape) Create a 'like' expression
Expression	literal(int type, java.lang.String text) Create a literal expression
Expression	unaryOperator(int operator, Expression operand) Create an unary operator expression

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultExpressionFactory

public DefaultExpressionFactory()

Method Detail

binaryOperator

public Expression binaryOperator(int operator,
                                 Expression left,
                                 Expression right)
                          throws SelectorException

Create a binary operator expression

Specified by:

binaryOperator in interface ExpressionFactory

Parameters:

operator - the operator token type from SelectorTokenTypes

left - the left-hand side of the binary expression

right - the right-hand side of the binary expression

Returns:

a new binary expression

Throws:

SelectorException - if the operator is not a valid binary operator

unaryOperator

public Expression unaryOperator(int operator,
                                Expression operand)
                         throws SelectorException

Create an unary operator expression

Specified by:

unaryOperator in interface ExpressionFactory

Parameters:

operator - the operator token type from SelectorTokenTypes

operand - the expression to apply the operator to

Returns:

a new unary expression

Throws:

SelectorException - if the operator is not a valid unary operator

identifier

public Expression identifier(java.lang.String name)
                      throws SelectorException

Create an identifier expression

Specified by:

identifier in interface ExpressionFactory

Parameters:

name - the name of the identifier

Returns:

a new identifier expression

Throws:

SelectorException - is name is not a valid identifier

isNull

public Expression isNull(Expression identifier)
                  throws SelectorException

Create an 'is null' expression

Specified by:

isNull in interface ExpressionFactory

Parameters:

identifier - the identifer expression to apply the 'is null' test

Returns:

an 'is null' expression

Throws:

SelectorException - for any error

like

public Expression like(Expression identifier,
                       java.lang.String pattern,
                       java.lang.String escape)
                throws SelectorException

Create a 'like' expression

Specified by:

like in interface ExpressionFactory

Parameters:

identifier - the identifer to apply the 'like' test to

pattern - the search pattern

escape - the escape character. This may be null

Returns:

a new 'like' expression

Throws:

SelectorException - if the pattern or escape is invalid

between

public Expression between(Expression num1,
                          Expression num2,
                          Expression num3)
                   throws SelectorException

Create a 'between' expression that returns the result of:
num1 >= num2 and num1 <= num3 when evaluated

Specified by:

between in interface ExpressionFactory

Parameters:

num1 - an arithmethic expression

num2 - an arithmethic expression

num3 - an arithmethic expression

Returns:

a new 'between' expression

Throws:

SelectorException - for any error

in

public Expression in(Expression identifier,
                     java.util.HashSet set)
              throws SelectorException

Create an 'in' expression

Specified by:

in in interface ExpressionFactory

Parameters:

identifier - string identifer to apply the 'in' test to

set - the set of string values to compare against

Returns:

a new 'in' expression

Throws:

SelectorException - for any error

literal

public Expression literal(int type,
                          java.lang.String text)
                   throws SelectorException

Create a literal expression

Specified by:

literal in interface ExpressionFactory

Parameters:

type - the operator token type from SelectorTokenTypes

text - the literal text

Returns:

a new literal expression

Throws:

SelectorException - if type is not a valid literal type