PHP Class izzum\statemachine\EntityBuilder
The entity returned is the application domain specific object that will be
injected in the Rules and Commands for a specific statemachine (eg: Order)
and can implement event handlers and callables.
A typical statemachine would use a subclass of this builder.
The Context can build the entity by using the associated Identity object of the
Context. the entity can be obtained via the factory method EntityBuilder::getEntity().
Of course, a specific Rule or Command can just accept the Identifier directly
and use the entity_id to generate the domain object itself. But this would
also mean that the Rules and Commands will not be specific to the applications'
problem domain but to that of the statemachine (and therefore possibly less
reusable). It is therefore advisable to let a builder build your domain model.
The Context instance is configured with this builder class by default. It can
be configured with a subclass for your application domain if necessary (and the
configuration can be done automatically by using a concrete instance of the AbstractFactory)
This class implements caching of the domain model/entity returned.
The builder is reusable for different statemachines (that have
a different Entity by definition). The cache will be rebuilt whenever a new
Identifier object is passed to the 'getEntity' method.
This specific class (in contrast to subclasses) returns the Identifier itself instead of a domain model.
This is useful because it allows us to test a lot of scenarios without side effects.
It also allows us to use the Identifier object for our rules and commands, so
you do not necessarily have to write your own entitybuilder.
This is a prime candidate to be overriden by subclasses (if need be).
Subclass this class and override the 'build' method to return a
domain specific object of choice. The building of that domain object depends
on the information in the Context, specifically the entity_id.
the builder can be configured via dependency injection at creation time so
the builder can make use of the injected data when it is called via 'getEntity'.
An example of a builder would be an 'EntityBuilderOrder' class,
which would be used for a statemachine that uses rules and commands to act
upon an 'Order' object from your applation domain.
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Open project: rolfvreijdenberger/izzum-statemachine
Class Usage Examples
Protected Properties
| Property |
Type |
Description |
|
| $entity |
Object |
a cached instance of the built entity object |
|
| $identifier |
Identifier |
a cached instance of the used Identifier. |
|
Public Methods
| Method |
Description |
|
|
__toString ( ) : string |
returns the string representation |
|
|
getEntity ( Identifier $identifier, boolean $create_fresh_entity = false ) : Object |
Gets an application domain specific model of choice, as implemented by a
subclass. |
|
|
toString ( ) : string |
returns the string representation |
|
Protected Methods
| Method |
Description |
|
|
build ( Identifier $identifier ) : Object |
the actual building function. |
|
Method Details
__toString()
public method
returns the string representation
Override this method to return an application specific domain model.
In an overriden function it is possible to use the state of the concrete
builder itself, which can be passed in via dependency injection at
construction time, so we have additional information on how to build the
domain object.
|
protected build ( Identifier $identifier ) : Object |
|
$identifier |
Identifier |
|
| return |
Object |
an object of any type defined by the subclass |
getEntity()
final public method
Gets an application domain specific model of choice, as implemented by a
subclass.
|
final public getEntity ( Identifier $identifier, boolean $create_fresh_entity = false ) : Object |
|
$identifier |
Identifier |
|
|
$create_fresh_entity |
boolean |
optional. if true, then a new instance is always created,
else it might be cached if used for the same Identifier
(performance).
Since a statemachine might run multiple transitions in memory
and alter the data in the persistence layer,
there might be a need to refresh the entity (create it again)
if the in memory object and the data
in the persistence layer are not synchronized. this might
cause rules or commands to act on
in-memory data while it should use the persisted data.
(an ORM should handle this automatically) |
| return |
Object |
an object of any type, depending on the statemachine.
This object will be used by the Rule and Command that go with a
certain statemachine. It will be injected in the constructor of
the
Rule and Command.
It implements caching so we always get the same entity instance
on
each call of 'getEntity' with the same Context |
returns the string representation
Property Details
$entity protected_oe property
a cached instance of the built entity object
|
protected Object $entity |
| return |
Object |
|
$identifier protected_oe property
a cached instance of the used Identifier.
|
protected Identifier,izzum\statemachine $identifier |
| return |
Identifier |
|