Ocl operations for Classifier

allInstances () : Set{T}

Returns a Set containing all of the existing instances of the current classifier (along with instances of all its inherited classifiers).

examples:

Expression	Result
let a : String = 'a', b : String = 'b', c : Integer = 2 in String.allInstances()	Set{'a','b'}

Ocl operations for OclAny

oclIsKindOf( Classifier typespec ) : Boolean

Returns true if the type of self corresponds to the type or supertype of typespec, false otherwise. This operation allows users to check the class hierarchy of self much like would an instanceof Java.

examples:

Expression	Result
anEmployee.oclIsKindOf(Employee)	true
anEmployee.oclIsKindOf(Person)	true
aCat.oclIsKindOf(Person)	false

oclIsTypeOf( typespec : Classifier ) : Boolean

Returns true if the type of self is the same as typespec, or false otherwise. This operation allows users to check the exact class type of self.

examples:

Expression	Result
anEmployee.oclIsTypeOf(Employee)	true
anEmployee.oclIsTypeOf(Person)	false
aCat.oclIsTypeOf(Person)	false

oclAsType ( typespec : Classifier ) : T

Returns self statically typed as typespec if it is an instance of this type. Note that this does not alter the runtime value of self, it only enables access to subtype operations. This operation allows users to cast self to another type.

examples:

Expression	Result
aPerson.oclAsType(Employee)	an object of Employee type

oclIsUndefined () : Boolean

Returns true if self is equal to invalid or null.

examples:

Expression	Result
let anObject : String = null in anObject.oclIsUndefined()	true
let anObject : String = invalid in anObject.oclIsUndefined()	true
let anObject : String = 'null' in anObject.oclIsUndefined()	false

oclIsInvalid () : Boolean

Returns true if self is equal to invalid.

examples:

Expression	Result
let anObject : String = null in anObject.oclIsUndefined()	false
let anObject : String = invalid in anObject.oclIsUndefined()	true
let anObject : String = 'null' in anObject.oclIsUndefined()	false

<> ( object : OclAny ) : Boolean

Returns true if self is a different object from object.

examples:

Expression	Result
let a : String = 'a', b : String = 'a' in a <> b	false
let a : Integer = 2, b : Real = 2.0 in a <> b	false
let a : Integer = -2, b : Integer = 2 in a <> b	true

= ( object : OclAny) : Boolean

Returns true if self is equal to object.

examples:

Expression	Result
let a : String = 'a', b : String = 'a' in a = b	true
let a : Integer = 2, b : Real = 2.0 in a = b	true
let a : Integer = -2, b : Integer = 2 in a = b	false

< ( object : T ) : Boolean

Returns true if self is comparable to object and less than object.

examples:

Expression	Result
let a : Integer = 1, b : Integer = 2 in a < b	true
let a : Real = 1.5, b : Integer = 2 in a < b	true
let a : String = 'Anteater', b : String = 'Aardvark' in a < b	false

> ( object : T ) : Boolean

Returns true if self is comparable to object and greater than object.

examples:

Expression	Result
let a : Integer = 1, b : Integer = 2 in a > b	false
let a : Real = 1.5, b : Integer = 2 in a > b	false
let a : String = 'Anteater', b : String = 'Aardvark' in a > b	true

<= ( object : T ) : Boolean

Returns true if self is comparable to object and less than or equal to object.

examples:

Expression	Result
let a : Integer = 1, b : Integer = 2 in a <= b	true
let a : Real = 1.5, b : Integer = 2 in a <= b	true
let a : String = 'Anteater', b : String = 'Aardvark' in a <= b	false

>= ( object : T ) : Boolean

Returns true if self is comparable to object and greater than or equal to object.

examples:

Expression	Result
let a : Integer = 1, b : Integer = 2 in a >= b	false
let a : Real = 1.5, b : Integer = 2 in a >= b	false
let a : String = 'Anteater', b : String = 'Aardvark' in a >= b	true

Ocl operations for String

A note on Strings : OCL Strings begin at index 1, not 0 as in most languages. Thus 'test'.at(0) fails in invalid whereas 'test'.at(1) yields 't'. Likewise, 'test'.substring(2, 2) returns 'e'.

size () : Integer

Returns the number of characters composing self.

examples:

Expression	Result
'size operation'.size()	14

concat ( s : String ) : String

Returns a string containing self followed by s.

examples:

Expression	Result
'concat'.concat(' ').concat('operation')	'concat operation'

substring ( lower : Integer, upper : Integer ) : String

Returns a string containing all characters from self starting from index lower up to index upper included. Both lower and upper parameters should be contained between 1 and self.size() included. lower cannot be greater than upper.

examples:

Expression	Result
'substring operation'.substring(11, 19)	'operation'
'substring operation'.substring(1, 1)	's'
'substring operation'.substring(0, 1)	Ø

toInteger () : Integer

Returns an Integer of value equal to self, or Ø if self does not represent an integer.

examples:

Expression	Result
'3.0'.toInteger()	Ø
'4'.toInteger()	4
'toInteger'.toInteger()	Ø

toReal () : Real

Returns a Real of value equal to self, or Ø if self does not represent a real.

examples:

Expression	Result
'3.0'.toReal()	3.0
'4'.toReal()	4.0
'toReal'.toReal()	Ø

toLower () : String

Returns self with all characters converted to lowercase.

examples:

Expression	Result
'LoWeR OpErAtIoN'.toLower()	'lower operation'

toUpper () : String

Returns self with all characters converted to uppercase.

examples:

Expression	Result
'UpPeR OpErAtIoN'.toUpper()	'UPPER OPERATION'

Ocl operations for Number

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.

Number::min ( r : Number ) : Number

Returns the lowest number between self and r.

examples:

Expression	Result
6.min(3)	6
6.min(5.2)	5.2
(2.3).min(3)	2.3
(2.3).min(5.2)	2.3

Number::max ( r : Number ) : Number

Returns the greatest number between self and r.

examples:

Expression	Result
6.max(3)	6
6.max(5.2)	6.0
(2.3).max(3)	3.0
(2.3).max(5.2)	5.2

Number::abs () : Number

Returns the absolute value of self, self if it is already a positive number.

examples:

Expression	Result
(-2.3).abs()	2.3
-5.abs()	5

Number::round () : Integer

Returns the nearest integer to self if it is a Real, self if it is an Integer.

examples:

Expression	Result
(2.3).round()	2
(2.5).round()	3
(2.8).round()	3
2.round()	2

Number::floor () : Integer

Returns the integer part of self if it is a Real, self if it is an Integer.

examples:

Expression	Result
(2.3).floor()	2
(2.8).floor()	2
2.floor()	2

Integer::div ( i : Integer ) : Integer

Returns the integer quotient of the division of self by i.

examples:

Expression	Result
3.div(2)	1
11.div(3)	3

Integer::mod ( i : Integer ) : Integer

Returns the integer remainder of the division of self by i.

examples:

Expression	Result
3.mod(2)	1
11.mod(3)	2

Ocl operations for Collection

Take note that collections in OCL can contain the null value (null) but not the invalid value (Ø). Trying to add Ø within a new or existing collection will yield Ø as a result. OCL proposes four distinct kind of collections offering all possibilities of ordering/unicity.

Collection type	Ordered	Unique
Sequence	true	false
OrderedSet	true	true
Bag	false	false
Set	false	true

count ( object : T ) : Integer

Returns how many times object is in the collection self.

examples:

Expression	Result
Sequence{2.3, 5.2}->count(5.2)	1
Set{3, 'test', 4.0, 4, 4.0, 'test'}->count(null)	0
Set{3, null, 4.0, null, 'test'}->count(null)	1
Bag{3, null, 4.0, null, 'test'}->count(null)	2

excludes ( object : T ) : Boolean

Returns true if object is not contained in self, false otherwise.

examples:

Expression	Result
Sequence{2.3}->excludes(2.1)	true
Sequence{2.0}->excludes(2)	false

excludesAll ( c2 : Collection(T) ) : Boolean

Returns true if no element of c2 is contained in self, false otherwise.

examples:

Expression	Result
Sequence{2.3, 5.2, 'a', 3, null}->excludesAll(Set{4, null})	false
Sequence{2.3, 5.2, 'a', 3}->excludesAll(Set{4, null})	true

includes ( object : T ) : Boolean

Returns true if object is contained in self, false otherwise.

examples:

Expression	Result
Sequence{2.3}->includes(2.1)	false
Sequence{2.0}->includes(2)	true

includesAll ( c2 : Collection(T) ) : Boolean

Returns true if all element of c2 are contained in self, false otherwise.

examples:

Expression	Result
Sequence{2.3, 5.2, 'a', 3, null}->includesAll(Set{3, null})	true
Sequence{2.3, 5.2, 'a', 3}->includesAll(Set{3, null})	false

isEmpty () : Boolean

Returns true if self is empty, false otherwise.

examples:

Expression	Result
Sequence{2, 'a'}->isEmpty()	false
Sequence{null}->isEmpty()	false
Sequence{}->isEmpty()	true

notEmpty () : Boolean

Returns true if self contains at least one element, false otherwise.

examples:

Expression	Result
Sequence{2, 'a'}->notEmpty()	true
Sequence{null}->notEmpty()	true
Sequence{}->notEmpty()	false

product ( c2 : Collection(T2) ) : Set(Tuple(first : T, second : T2))

Returns a Set of Tuples which represents the cartesian product of self with c2.

examples (notation of the tuples has been simplified):

Expression	Result
Sequence{3, 4}->product(Bag{3.0, 4.0})	Set{Tuple{3, 3.0}, Tuple{3, 4.0}, Tuple{4, 3.0}, Tuple{4, 4.0}}
Set{3, 4}->product(OrderedSet{3.0, 4.0})	Set{Tuple{3, 3.0}, Tuple{3, 4.0}, Tuple{4, 3.0}, Tuple{4, 4.0}}

size () : Boolean

Returns the number of elements contained in self.

examples:

Expression	Result
Sequence{2.3, 5}->size()	2
Sequence{}->size()	0

sum () : Real

Returns the sum of all elements contained in self if they support the '+' operation.

examples:

Expression	Result
Sequence{2.3, 5.2} in c->sum()	7.5
Sequence{2, 4} in c->sum()	6
Sequence{2, '4'} in c->sum()	Ø

exists ( expr : OclExpression ) : Boolean

Returns true if at least one element in self validates the condition expr, false otherwise. The evaluation is shortcut as soon as one element validating expr is found.

examples:

Expression	Result
Sequence{2.3, 5.2}->exists(self > 3)	true

forAll ( expr : OclExpression ) : Boolean

Returns true if the elements contained in self all validate the condition expr, false otherwise.

examples:

Expression	Result
Sequence{2.3, 5.2}->forAll(self > 3)	false
Sequence{2.3, 5.2}->forAll(self > 1.2)	true

isUnique ( expr : OclExpression ) : Boolean

Returns true if all elements contained in self evaluate to a distinct value for expr.

examples:

Expression	Result
Sequence{2.3, 5.2}->isUnique(self > 3)	true
Sequence{2.3, 5.2}->isUnique(self > 1)	false

one ( expr : OclExpression ) : Boolean

Returns true if there is only one element contained in self that validates the condition expr, false otherwise.

examples:

Expression	Result
Sequence{1.2, 2.3, 5.2, 0.9}->one(self < 1)	true
Sequence{1.2, 2.3, 5.2, 0.9}->one(self < 2)	false

any ( expr : OclExpression ) : T

Returns any element contained in self that validates the condition expr, null otherwise. Evaluation is shortcut as soon as an element validating expr is found. Note that the result of this on unordered collections will be random if more than one element validates expr.

examples:

Expression	Result
Sequence{1.2, 2.3, 5.2, 0.9}->any(self < 1)	0.9
Sequence{1.2, 2.3, 5.2, 0.9}->any(self < 2)	1.2

collect ( expr : OclExpression ) : Collection(T2)

Returns a collection containing the result of applying expr on all elements contained in self.

examples:

Expression	Result
Sequence{'first', 'second'}->collect(toUpper())	Sequence{'FIRST', 'SECOND'}

collectNested ( expr : OclExpression ) : Collection(T2)

Returns a collection containing all the elements contained in self on which we applied the OclExpression expr. The results won't be flattened. The type of the resulting collection depends on the type of self.

examples:

For the purpose of these examples we'll assume here that we have a Class Person with a reference children. Our model contains two persons such as person1.children = {James, Jane} and person2.children = {John}.

Expression	Result
self.persons->collectNested(children.firstname)	Sequence{Sequence{James, Jane}, Sequence{John}}

flatten () : Collection(T2)

Returns a collection containing all elements of self recursively flattened. Note : at the time of writing, the OCL standard library sports a bug which changes OrderedSets in Sets when flattening.

examples:

Expression	Result
Sequence{Set{1, 2, 3}, Sequence{2.0, 3.0}, Bag{'test'}}->flatten()	Sequence{1, 2, 3, 2.0, 3.0, 'test'}
Bag{Set{Bag{'test', 2, 3.0}}, Sequence{OrderedSet{2.0, 3, 1}}}->flatten()	Bag{1, 2, 3, 2.0, 3.0, 'test'}
OrderedSet{Set{Bag{'test', 2, 3.0}}, Sequence{Set{2.0, 3, 1}}}->flatten()	Set{3.0, 2, 1, 3, 'test', 2.0}
Set{Set{Bag{'test', 2, 3.0}}, Sequence{OrderedSet{2.0, 3, 1}}}->flatten()	Set{3.0, 2, 1, 3, 'test', 2.0}

including ( object : T ) : Collection(T)

Returns a collection containing all elements of self followed by object. Note : at the time of writing, the OCL standard library sports a bug which changes OrderedSets in Sets when including elements.

examples:

Expression	Result
Sequence{'a', 'b'}->including('c')	Sequence{'a', 'b', 'c'}
Bag{'a', 'b'}->including('c')	Bag{'a', 'c', 'b'}
OrderedSet{'a', 'b'}->including('c')	Set{'a', 'c', 'b'}
Set{'a', 'b'}->including('c')	Set{'a', 'c', 'b'}

excluding ( object : T ) : Collection(T)

Returns a collection containing all elements of self minus all occurences of object. Note : at the time of writing, the OCL standard library sports a bug which changes OrderedSets in Sets when excluding elements.

examples:

Expression	Result
Sequence{'b', 'a', 'b', 'c'}->excluding('b')	Sequence{'a', 'c'}
Bag{'b', 'a', 'b', 'c'}->excluding('b')	Bag{'c', 'a'}
OrderedSet{'b', 'a', 'b', 'c'}->excluding('b')	Set{'c', 'a'}
Set{'b', 'a', 'b', 'c'}->excluding('b')	Set{'c', 'a'}

select ( expr : OclExpression ) : Collection(T)

Returns a collection with all elements of self that validate the OclExpression expr.

examples:

Expression	Result
Sequence{1, 2, 3}->select(i : Integer | i > 1)	Sequence{2, 3}
Bag{1, 2, 3}->select(i : Integer | i > 1 )	Bag{3, 2}
OrderedSet{1, 2, 3}->select(i : Integer | i > 1 )	OrderedSet{2, 3}
Set{1, 2, 3}->select(i : Integer | i > 1 )	Set{3, 2}

reject ( expr : OclExpression ) : Collection(T)

Returns a collection with all elements of self except for those who validate the OclExpression expr.

examples:

Expression	Result
Sequence{1, 2, 3}->reject(i : Integer | i > 1 )	Sequence{1}
Bag{1, 2, 3}->reject(i : Integer | i > 1 )	Bag{1}
OrderedSet{1, 2, 3}->reject(i : Integer | i > 1 )	OrderedSet{1}
Set{1, 2, 3}->reject(i : Integer | i > 1 )	Set{1}

sortedBy ( expr : OclExpression ) : Sequence(T)

Returns a sorted collection containing all elements from self sorted in accordance with the OclExpression expr. This can be used on all kind of collections yet will always yield a Sequence-typed result except for OrderedSet which returns an OrderedSet.

examples:

For the purpose of these examples we'll assume here that we have a Class Employee with an attribute age. Our model contains two employees such as employee1.age = 24 and employee2.age = 27.

Expression	Result
self.employees->sortedBy(age)	Sequence{employee1, employee2}

asBag () : Bag(T)

Returns a Bag containing all elements of self.

examples:

Expression	Result
Sequence{'3', 1, 2.0, '3'}->asBag()	Bag{2.0, '3', 1, '3'}
Bag{1, 2.0, '3'}->asBag()	Bag{2.0, 1, '3'}
OrderedSet{1, 2.0, '3'}->asBag()	Bag{2.0, 1, '3'}
OrderedSet{1, 1, 2.0, '3'}->asBag()	Bag{'3', 1, 2.0}
Set{1, 2.0, '3'}->asBag()	Bag{2.0, 1, '3'}
Set{1, 1, 2.0, '3'}->asBag()	Bag{2.0, '3', 1}

asSet () : Set(T)

Returns a Set containing all elements of self.

examples:

Expression	Result
Sequence{1, 2.0, '3'}->asSet()	Set{1, '3', 2.0}
Sequence{1, 1, 2.0, '3'}->asSet()	Set{'3', 1, 2.0}
Bag{1, 2.0, '3'}->asSet()	Set{2.0, 1, '3'}
Bag{1, 1, 2.0, '3'}->asSet()	Set{1, '3', 2.0}
OrderedSet{1, 2.0, '3'}->asSet()	Set{1, '3', 2.0}
OrderedSet{1, 1, 2.0, '3'}->asSet()	Set{'3', 1, 2.0}
Set{1, 2.0, '3'}->asSet()	Set{2.0, 1, '3'}
Set{1, 1, 2.0, '3'}->asSet()	Set{'3', 1, 2.0}

asSequence () : Boolean

Returns a Sequence containing all elements of self. Element ordering is preserved when possible.

examples:

Expression	Result
Sequence{1, 2.0, '3'}->asSequence()	Sequence{1, 2.0, '3'}
Bag{1, 2.0, '3'}->asSequence()	Sequence{2.0, 1, '3'}
OrderedSet{1, 2.0, '3'}->asSequence()	Sequence{1, 2.0, '3'}
Set{1, 2.0, '3'}->asSequence()	Sequence{'3', 1, 2.0}

asOrderedSet () : OrderedSet(T)

Returns an OrderedSet containing all elements of self. Element ordering is preserved when possible.

examples:

Expression	Result
Sequence{1, 2.0, '3'}->asOrderedSet()	OrderedSet{1, '3', 2.0}
Sequence{1, 1, 2.0, '3'}->asOrderedSet()	OrderedSet{'3', 1, 2.0}
Bag{1, 2.0, '3'}->asOrderedSet()	OrderedSet{2.0, 1, '3'}
Bag{1, 1, 2.0, '3'}->asOrderedSet()	OrderedSet{1, '3', 2.0}
OrderedSet{1, 2.0, '3'}->asOrderedSet()	OrderedSet{1, 2.0, '3'}
Set{1, 2.0, '3'}->asOrderedSet()	OrderedSet{'3', 1, 2.0}

Ocl operations for Boolean

1. Operation OR

   Or	true	false	Ø
   true	true	true	true
   false	true	false	Ø
   Ø	true	Ø	Ø

2. Operation AND

   And	true	false	Ø
   true	true	false	true
   false	false	false	false
   Ø	Ø	false	Ø

3. Operation XOR

   Xor	true	false	Ø
   true	false	true	Ø
   false	true	false	Ø
   Ø	Ø	Ø	Ø

4. Operation IMPLIES

   Implies	true	false	Ø
   true	true	false	Ø
   false	true	true	true
   Ø	true	Ø	Ø

5. Operation NOT

   Not	Result
   true	false
   false	true
   Ø	Ø

Glossary

invalid

invalid is the singleton instance of the OCLInvalid type. It is returned whenever an evaluation fails, whatever the cause. Referred to as Ø in this guide.

Ø

See invalid.