public interface Prototype extends Cloneable, Setup
The purpose of a prototype is to make it possible to ask classes, determined at run-time by user parameters, to instantiate themselves very many times without using the Reflection library, which would be very inefficient.
ECJ makes extensive use of Prototypes. Individuals are prototypes. Species are prototypes. Fitness objects are prototypes. Breeding pipelines and selection methods are prototypes. In the GP section, GPNodes and GPTrees are prototypes. In the Rule section, Rulesets and Rules are prototypes. In the Vector section, Genes are prototypes. And so on.
ECJ uses Prototypes almost exclusively instead of calling new. This is because new requires that you know, in your code, the exact class of the object to be created. Doing so programmatically essentially precludes being able to set up object graphs dynamically from parameter files.
Sadly, clone() is rather slower than calling new. However it is a lot faster than calling java.lang.Class.newInstance(), and somewhat faster than rolling our own "cloner" method.
Prototypes must be Cloneable, Serializable (through Setup), and of course, Setup.
| Modifier and Type | Method and Description |
|---|---|
Object |
clone()
Creates a new individual cloned from a prototype,
and suitable to begin use in its own evolutionary
context.
|
Parameter |
defaultBase()
Returns the default base for this prototype.
|
void |
setup(EvolutionState state,
Parameter base)
Sets up the object by reading it from the parameters stored
in state, built off of the parameter base base.
|
Object clone()
Typically this should be a full "deep" clone. However, you may share certain elements with other objects rather than clone hem, depending on the situation:
Implementations.
public Object clone()
{
try
{
return super.clone();
}
catch ((CloneNotSupportedException e)
{ throw new InternalError(); } // never happens
}
public Object clone()
{
try
{
MyObject myobj = (MyObject) (super.clone());
// put your deep-cloning code here...
}
catch ((CloneNotSupportedException e)
{ throw new InternalError(); } // never happens
return myobj;
}
public Object clone()
{
MyObject myobj = (MyObject) (super.clone());
// put your deep-cloning code here...
return myobj;
}
void setup(EvolutionState state, Parameter base)
For prototypes, setup(...) is typically called once for the prototype instance; cloned instances do not receive the setup(...) call. setup(...) may be called more than once; the only guarantee is that it will get called at least once on an instance or some "parent" object from which it was ultimately cloned.
Parameter defaultBase()
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