MatchExpression Class Reference

#import <MatchExpression.h>

Inherits NSObject.

Instance Methods
(id)	- initWithVarName:condition:value:
(MatchExpression *)	- and:condition:value:
(MatchExpression *)	- or:condition:value:
(BOOL)	- hasNext
(MatchExpression *)	- rewind
(NSString *)	- asString
(id< ISFSArray >)	- toSFSArray
(id< ISFSArray >)	- expressionAsSFSArray

Class Methods
(id)	+ expressionWithVarName:condition:value:

Properties
NSString *	varName
id< IMatcher >	condition
id	value
LogicOperator *	logicOp
MatchExpression *	parent
MatchExpression *	next

Detailed Description

Match Expressions are built like "if" conditions in any common programming language.

They work like queries in a database and can be used to search for Rooms or Users using custom criteria. These expressions are extremely easy to create and concatenate and they can be used for many different filtering operations within the SFS2X framework.

This is a quick example:

MatchExpression *exp = [MatchExpression expressionWithVarName:@"rank" condition:[NumberMatch numberMatchGreaterThan] value:[NSNumber numberWithInt:5]];
exp = [exp and:@"country" condition:[StringMatch stringMatchEquals] value:@"Italy"];

Expressions are made of three elements:

• Variable name
• Match operator
• Value

Additionally any number of expressions can be linked together with a logical AND / OR operator, just like in regular code. In the above example we have created an expression that will check for a rank value > 5 and a country value == "Italy".

The search options are not just limited to User/Room Variables name. In fact the Matching engine provides two extra classes, RoomProperties and UserProperties, where you can access many specific attributes of the Room and User class.

See also

RoomProperties

UserProperties

Method Documentation

and:condition:value:

- (MatchExpression *) and:		(NSString *)	varName
condition:		(id <IMatcher>)	condition
value:		(id)	value

Concatenate the current expression with a new one using the logical AND operator

Parameters

varName	name of the variable/property to match
condition	the match condition
value	the value to match against

return a new MatchExpression

expressionWithVarName:condition:value:

+ (id) expressionWithVarName:		(NSString *)	varName
condition:		(id <IMatcher>)	condition
value:		(id)	value

Parameters

varName	name of the variable/property to match
condition	the match condition
value	the value to match against

hasNext

- (BOOL) hasNext

Check if the current expression is concatenated to another one via a logic operator

See also

LogicOperator

or:condition:value:

- (MatchExpression *) or:		(NSString *)	varName
condition:		(id <IMatcher>)	condition
value:		(id)	value

Concatenate the current expression with a new one using the logical OR operator

Parameters

varName	name of the variable/property to match
condition	the match condition
value	the value to match against

return a new MatchExpression

rewind

- (MatchExpression *) rewind

Rewinds the cursor to the first expression in the chain and return the MatchExpression at the top of the chain of expressions

Property Documentation

condition

- (id<IMatcher>) condition

readwritenonatomicstrong

Get the condition used for matching

See also

BoolMatch

NumberMatch

StringMatch

logicOp

- (LogicOperator*) logicOp

readwritenonatomicstrong

Get the current logic operator, could be null if the expression has no other concatenated expressions

See also

LogicOperator

next

- (MatchExpression*) next

readwritenonatomicstrong

Get the next expression chained to the current one.

value

- (id) value

readwritenonatomicstrong

The value used to test the condition in the expression

varName

- (NSString*) varName

readwritenonatomicstrong

Get the name of the variable or property that is being matched.

This can be the name of a User/Room variable or a property from the classes listed below.

See also

RoomProperties

UserProperties