OCLOperators
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== General operators ==
OCL operators define constraints and operations on objects in an object-oriented programming language like Java, C++, or C#. They are also used in OCL expressions to specify constraints on objects or perform operations on object properties.
To find all available you can open the OCL-Editor and type in a class:


[[File:Ocl-editor 1.png|frameless|433x433px|link=https://wiki.mdriven.net/index.php/File:Ocl-editor_1.png]]
For example, let's say we have a class called "Person" with properties like: "name," "age," and "gender." We can use OCL operators to define constraints on the properties of the "Person" class. Here are some examples:
{| class="wikitable"
# To define a constraint that ensures that the "age" property of a "Person" object is greater than or equal to 18, we can use the greater than or equal to (>=) operator as follows:  <code>context Person: self.age >= 18</code>
!Operators
# To define a constraint that ensures that the "gender" property of a "Person" object is either "Male" or "Female," we can use the OR (||) operator as follows:  <code>context Person: self.gender = 'Male' or self.gender = 'Female'</code>
!Description
# To define a constraint that ensures that the "name" property of a "Person" object starts with an uppercase letter, we can use the dot notation (.) and the regular expression operator (matches) as follows:  <code>context Person: self.name.matches('^[A-Z]')</code>
|-
In addition to defining constraints, OCL operators can also perform operations on object properties. For example, we can use the sum() operator to calculate the sum of all the elements in a collection property of a "Person" object as follows: <code>context Person: self.salary.sum() < 100000</code>
|'''[[Allinstances operator|Allinstances]]'''
|All the objects of the class
|-
|'''[[OCLOperators allInstancesAtTime|allinstancesAtTime]]'''
|All the currently loaded instances
|-
|[[OCLOperators allLoadedObjects|allLoadedObjects]]
|All objects currently in memory, exckluding deleted objects
|-
|'''[[OCLOperators allStates|allStates]]'''
|Meta information about available states in state machines the class may contain
|-
|'''[[OCLOperators allSubClasses|allSubClasses]]'''
|Meta information on all the sub classes this class has
|-
|'''[[OCLOperators allSuperTypes|allSuperTypes]]'''
|Meta information on all the super classes – in inheritance order the class has
|-
|[[OCLOperators ASCII|ASCII]]
|
|-
|'''[[OCLOperators associationEnds|associationEnds]]'''
|Returns a collection of strings with association names for the class
|-
|[[OCLOperators associationEndsWithType|associationEndsWithType]]
|Returns a collection of strings with association names and type information for the class
|-
|'''[[OCLOperators asString|Asstring]]'''
|The string representation of the class – the asString operation is available on everything
|-
|[[OCLOperators AsTaJson|asTaJson]]
|Returns ajson string defined by the ViewModel
|-
|[[OCLOperators atTime|atTime]]
|
|-
|'''[[OCLOperators attributes|Attributes]]'''
|Meta information about what attributes the class has
|-
|[[OCLOperators BigEndianUnicode|BigEndianUnicode]]
|
|-
|[[OCLOperators brokenConstraints|brokenConstraints]]
|Returns a collection of the names of broken constraints for the class and object.
|-
|[[OCLOperators canAccess|canAccess]]
|
|-
|'''[[OCLOperators constraints|Contraints]]'''
|Meta information on what constraints the class has
|-
|[[OCLOperators count|count]]
|Returns how many times ''object'' is in the collection ''self''.
|-
|[[OCLOperators Default|Default]]
|
|-
|[[OCLOperators Empty|Empty]]
|
|-
|'''[[OCLOperators emptyList|emptylist]]'''
|Returns an empty list typed to hold objects of the class
|-
|[[OCLOperators existing|existing]]
|
|-
|[[OCLOperators externalId|externalId]]
|
|-
|[[OCLOperators format|format]]
|
|-
|[[OCLOperators IsDirty|IsDirty]]
|
|-
|[[OCLOperators IsNew|IsNew]]
|IsNew operator returns true if the object has never been saved to the database.
|-
|'''isDirtyMember'''
|
|-
|'''isNull'''
|
|-
|'''[[OCLOperators nullValue|nullValue]]'''
|A typed null value
|-
|'''[[OCLOperators objectfromExternalId|objectFromExternalId]]'''
|An external identity will be resolved to the object
|-
|'''[[OCLOperators oclAsType|oclAsType]]'''
|The type of the class
|-
|[[OCLOperators oclGetStates|oclGetStates]]
|
|-
|'''[[oclIsInvalid]]'''
|Returns true if ''self'' is equal to *invalid*.
|-
|'''[[OCLOperators oclIsKindOf|oclIsKindOf]]'''
|This is to if a class is a subclass or a the class itself and not unrelated
|-
|'''[[OCLOperators oclIsTypeOf|oclIsTypeOf]]'''
|Returns true if
|-
|[[OCLOperators OnCreate|OnCreate]]
|
|-
|[[OCLOperators OnUpdate|OnUpdate]]
|
|-
|'''[[OCLOperators oclSingleton|oclSingleton]]'''
|Classes that implements the Singleton pattern – by setting IsSingleton=true – will return the singleton instance with this operator
|-
|[[oclIsUndefined]]
|Returns true if ''self'' is equal to invalid or null.
|-
|'''[[OCLOperators OclType|OclType]]'''
|
|-
|'''safeCast'''
|
|-
|'''superTypes'''
|
|-
|'''[[OCLOperators taggedValue|TaggedValue]]'''
|Meta information on tagged values set in the class
|-
|'''[[OCLOperators taggedValueOnFeature|TaggedValueOnFeature]]'''
|Meta information on Tagged values set on a named feature in the class
|-
|'''[[OCLOperators typename|Typename]]'''
|The type name as a string
|-
|'''[[OCLOperators ViewModels|ViewModels]]'''
|A tuple with the ViewModels for this class a members
|}


== Collection operators ==
OCL operators make it easy to write correct and maintainable object-oriented programs.
Once you have a collection of objects there are certain operators that are applicable to it.  


See this page for [[examples on collection operators]]
== Examples of OCL Operators  ==
 
Again you can use the OCL-Editor to see what they are:
 
[[File:Collection of objects operators.png|frameless|453x453px|link=https://wiki.mdriven.net/index.php/File:Collection_of_objects_operators.png]]
{| class="wikitable"
{| class="wikitable"
!Operators
|'''Type'''
!Description
|'''Description'''
|-
|'''[[OCLOperators any|->any]]'''
|Returns any element contained in ''self'' that validates the condition ''expr'', null otherwise. 
|-
|'''[[OCLOperators append|->append]]'''
|Add another object last
|-
|-
|'''[[OCLOperators asBag|->asBag]]'''
|[https://wiki.mdriven.net/index.php/Category:OCL_General_Operators General Operators]
|Returns a Bag containing all elements of ''self''.
|used to manipulate and query objects
|-
|-
|'''[[OCLOperators asSequence|->asSequence]]'''
|[https://wiki.mdriven.net/index.php/Category:OCL_Collection_Operators Collection Operators]
|Returns a Sequence containing all elements of ''self''. Element ordering is preserved when possible.
|operators applicable to a collection of objects
|-
|-
|'''[[OCLOperators asSet|->asSet]]'''
| [https://wiki.mdriven.net/index.php/Category:OCL_String_Operators String Operators]
|Returns a Set containing all elements of ''self''.
|used to manipulate and compare string values
|-
|-
|'''[[OCLOperators at|->at]]'''
|[https://wiki.mdriven.net/index.php/Category:OCL_Number_Operators Number Operators]
|Get the objects at X where the first index is 1
|used to perform arithmetic and comparison operations on numeric values
|-
|-
|'''[[OCLOperators at0|->at0]]'''
|[https://wiki.mdriven.net/index.php/Category:OCL_Boolean_Operators Boolean Operators]
|Get the objects at X where the first index is 0
|used to evaluate and compare Boolean expressions
|-
|-
|'''[[OCLOperators collect|->collect]]'''
|[https://wiki.mdriven.net/index.php/Category:OCL_ViewModel_Operators ViewModel Operators](on selfVM variable)
|Returns a collection containing the result of applying ''expr'' on all elements contained in ''self''.
|used to manipulate and interact with data in a ViewModel class of an application.
|-
|-
|[[OCLOperatorscollectNested|collectNested]]
|Returns a collection containing all the elements contained in ''self'' on which we applied the OclExpression ''expr''.
|-
|'''[[OCLOperators count|->count]]'''
|Count how many meet a certain criteria
|-
|[[OCLOperators Excludes|excludes]]
|Returns true if ''object'' is not contained in ''self'', false otherwise.
|-
|[[OCLOperatorsExcludesAll|excludesAll]]
|Returns true if no element of *c2* is contained in ''self'', false otherwise.
|-
|[[OCLOperators dictionary|'''->dictionary''']]
|Efficiently looks up values
|-
|'''[[OCLOperators difference|->difference]]'''
|The difference between 2 collections
|-
|'''[[OCLOperators excluding|->excluding]]'''
|The collection except this single object
|-
|'''[[OCLOperators exists|->exists]]'''
|Returns true if at least one element in ''self'' validates the condition ''expr'', false otherwise.
|-
| [[OCLOperatorsFlatten|->flatten]]
|Returns a collection containing all elements of ''self'' recursively flattened.
|-
|'''[[OCLOperators filterOnType|->filterOnType]]'''
|Only keep the ones of a certain type
|-
|'''[[OCLOperators first|->first]]'''
|Return the first object
|-
|'''[[OCLOperators forAll|->forAll]]'''
|Returns true if the all the elements contained in ''self'' validate the condition ''expr'', false otherwise.
|-
|'''[[OCLOperators groupBy|->groupBy]]'''
|Build collection of tuples grouped by some aspect
|-
|'''[[OCLOperators includes|->includes]]'''
|Does the collection include the object
|-
|'''[[OCLOperators includesAll|->includesAll]]'''
|Does the collection include the whole other collection
|-
|'''[[OCLOperators including|->including]]'''
|Returns the list with the element in the parameter included.
|-
|'''[[OCLOperators indexOf|->IndexOf]]'''
|The 1 based index of an object in the collection possibly -1 if not existing
|-
|'''[[OCLOperators indexOf0|->indexOf0]]'''
|The 0 based index of an object in the collection possibly -1 if not existing
|-
|'''[[OCLOperators intersection|->intersection]]'''
|The intersection of two collections
|-
|'''[[OCLOperators isEmpty|->isEmpty]]'''
|Returns true if the collection is empty
|-
|[[OCLOperatorsIsUnique|isUnique]]
|Returns true if all elements contained in ''self'' evaluate to a distinct value for ''expr''.
|-
|[[OCLOperatorsNotEmpty|notEmpty]]
|Returns true if ''self'' contains at least one element, false otherwise.
|-
|[[OCLOperatorsOne|one]]
|Returns true if there is only one element contained in ''self'' that validates the condition ''expr'', false otherwise.
|-
|'''[[OCLOperators last|->last]]'''
|Returns the last object in the collection
|-
|'''[[OCLOperators notEmpty|->notEmpty]]'''
|Returns true of the collection is not empty
|-
|'''[[OCLOperators orderBy|->orderBy]]'''
|Sorts the collection on one or more properties
|-
|'''[[OCLOperators orderDescending|->orderDescending]]'''
|Sort the from biggest to smallest
|-
|'''[[OCLOperators orderGeneric|->orderGeneric]]'''
|Sorts the list of properties with interchangeable sort order: (expr1, OclSortDirection::ascending, expr2, OclSortDirection::descending...)
|-
|'''[[OCLOperators prepend|->prepend]]'''
|Returns an OrderedSet containing ''object'' followed by all elements of ''self''.
|-
|'''[[OCLOperators reject|->reject]]'''
|Returns the objects not matching the criteria
|-
|'''[[OCLOperators select|->select]]'''
|Returns the objects matching the criteria
|-
|'''[[OCLOperators size|->size]]'''
|Returns the number of elements in the collection
|-
|'''[[OCLOperators subSequence|->subsequence]]'''
|Returns a smaller collection from a start to stop
|-
|'''[[OCLOperators symmetricDifference|->symmetricDifference]]'''
|The symmetric difference between the collections; ie all the objects in collection1 or collection2 but not in both
|-
|'''[[OCLOperators union|->union]]'''
|The set of objects in collection1 and objects in collection2
|}
== String operators ==
{| class="wikitable"
!Operators
!Description
|-
|[[Escape codes]]
|Escape (special) characters used in OCL
|-
|[[OCLOperators StringToAnsiBase64|StringToAnsiBase64]]
|Convert a string to an ANSI (1252) and as a base64 string
|-
|[[OCLOperators StringToEncodedBase64|StringToEncodedBase64]]
|Convert a string to a specific encoding and as a base64 string. For example Western Eauropean (ISO) Codepage 28591
|-
|[[OCLOperators Size () : Integer|size () : Integer]]
|Returns the number of characters composing ''self''.
|-
|[[OCLOperators subString|subString]]
|Returns the substring of the string operated on. The substring starts at parameter 1 and ends at parameter 2. The counting is 1-based.
|-
|[[OCLOperators ToInteger () : Integer|toInteger () : Integer]]
|Returns ''self'' with all characters converted to lowercase.
|-
|[[OCLOperators ToLower () : String|toLower () : String]]
|Returns ''self'' with all characters converted to lowercase.
|-
|[[OCLOperators ToReal () : Real|toReal () : Real]]
|Returns a Real of value equal to ''self''<nowiki>, or |invalid| if </nowiki>''self'' does not represent a real.
|-
|[[OCLOperators ToUpper () : String|toUpper () : String]]
|Returns self with all characters converted to uppercase.
|}
|}


== Number operators ==
  [[Category:OCL]]
In addition to the basic math functions (+, -, /, \*) are a number of advanced functions. Take note that *Number* denotes both *Integer* and *Real*, and they're substitutive unless otherwise specified.
{| class="wikitable"
!Operators
!Description
|-
|[[OCLOperators Number::abs () : Number|Number::abs () : Number]]
|Returns the absolute value of ''self'', ''self'' if it is already a positive number.
|-
|[[OCLOperators Number::floor () : Integer|Number::floor () : Integer]]
|Returns the integer part of self if it is a Real, self if it is an Integer.
|-
|[[OCLOperators Number::max ( r : Number ) : Number|Number::max ( r : Number ) : Number]]
|Returns the greatest number between self and *r*.
|-
|[[OCLOperators Number::min ( r : Number ) : Number|Number::min ( r : Number ) : Number]]
|Returns the lowest number between ''self'' and *r*.
|-
|[[OCLOperators Number::round () : Integer|Number::round () : Integer]]
|Returns the nearest integer to ''self'' if it is a Real, ''self'' if it is an Integer.
|-
|[[OCLOperators Integer::div ( i : Integer ) : Integer|Integer::div ( i : Integer ) : Integer]]
|Returns the integer quotient of the division of ''self'' by *i*.
|-
|[[OCLOperators Integer::mod ( i : Integer ) : Integer|Integer::mod ( i : Integer ) : Integer]]
|Returns the integer remainder of the division of ''self'' by *i*.
|}
== Viewmodel operators (on selfVM variable) ==
See page [[SelfVM]]
[[Category:OCL]]
[[Category:Beginner]]
[[Category:Beginner]]
[[Category:OCLOperators]]
[[Category:OCLOperators]]

Latest revision as of 05:27, 11 January 2024

OCL operators define constraints and operations on objects in an object-oriented programming language like Java, C++, or C#. They are also used in OCL expressions to specify constraints on objects or perform operations on object properties.

For example, let's say we have a class called "Person" with properties like: "name," "age," and "gender." We can use OCL operators to define constraints on the properties of the "Person" class. Here are some examples:

  1. To define a constraint that ensures that the "age" property of a "Person" object is greater than or equal to 18, we can use the greater than or equal to (>=) operator as follows: context Person: self.age >= 18
  2. To define a constraint that ensures that the "gender" property of a "Person" object is either "Male" or "Female," we can use the OR (||) operator as follows: context Person: self.gender = 'Male' or self.gender = 'Female'
  3. To define a constraint that ensures that the "name" property of a "Person" object starts with an uppercase letter, we can use the dot notation (.) and the regular expression operator (matches) as follows: context Person: self.name.matches('^[A-Z]')

In addition to defining constraints, OCL operators can also perform operations on object properties. For example, we can use the sum() operator to calculate the sum of all the elements in a collection property of a "Person" object as follows: context Person: self.salary.sum() < 100000

OCL operators make it easy to write correct and maintainable object-oriented programs.

Examples of OCL Operators

Type Description
General Operators used to manipulate and query objects
Collection Operators operators applicable to a collection of objects
String Operators used to manipulate and compare string values
Number Operators used to perform arithmetic and comparison operations on numeric values
Boolean Operators used to evaluate and compare Boolean expressions
ViewModel Operators(on selfVM variable) used to manipulate and interact with data in a ViewModel class of an application.
This page was edited more than 1 years ago on 01/11/2024. What links here
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