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In computer science, a mutator method is a method used to control changes to a variable. They are also widely known as setter methods. Often a setter is accompanied by a getter, which returns the value of the private member variable. They are also known collectively as accessors.
A property, in some object-oriented programming languages, is a special sort of class member, intermediate in functionality between a field (or data member) and a method.The syntax for reading and writing of properties is like for fields, but property reads and writes are (usually) translated to 'getter' and 'setter' method calls.
This is typically accomplished by augmenting an accessor method (or property getter) to check whether a private member, acting as a cache, has already been initialized. If it has, it is returned straight away. If not, a new instance is created, placed into the member variable, and returned to the caller just-in-time for its first use.
Sometimes these accessor methods are called getX and setX (where X is the field's name), which are also known as mutator methods. Usually the accessor methods have public visibility while the field being encapsulated is given private visibility - this allows a programmer to restrict what actions another user of the code can perform. [ 1 ]
Properties are implemented by way of the @synthesize keyword, which generates getter (and setter, if not read-only) methods according to the property declaration. Alternatively, the getter and setter methods must be implemented explicitly, or the @dynamic keyword can be used to indicate that accessor methods will be provided by other means.
METHOD-ID. GET PROPERTY bar. DATA DIVISION. LINKAGE SECTION. return-var declaration PROCEDURE DIVISION RETURNING return-var. instructions. END METHOD. METHOD-ID. SET PROPERTY bar. DATA DIVISION. LINKAGE SECTION. value-var declaration PROCEDURE DIVISION USING value-var. instructions. END METHOD. METHOD-ID. GET PROPERTY bar. DATA DIVISION ...
A method is a behavior of an object parametrized by a user. Data is represented as properties of the object, and behaviors are represented as methods. For example, a Window object could have methods such as open and close, while its state (whether it is open or closed at any given point in time) would be a property.
Unlike Smalltalk, in Dart the value of a cascaded method invocation is the receiver (base object), not the value of the (uncascaded) method invocation, and thus there is no need for yourself. Dart uses properties , and thus rather than using method syntax for getters and setters ( foo.getBar(); foo.setBar(b); ), it uses field value/assignment ...