Package io.jenetics.prog.op

Class EphemeralConst<T>

java.lang.Object

io.jenetics.prog.op.Val<T>

io.jenetics.prog.op.EphemeralConst<T>

All Implemented Interfaces:

Op<T>, Serializable, Function<T[],T>, Supplier<Op<T>>

public final class EphemeralConst<T>
extends Val<T>
implements Op<T>, Serializable

Implementation of an ephemeral constant. It causes the insertion of a mutable constant into the operation tree. Every time this terminal is chosen a, different value is generated which is then used for that particular terminal, and which will remain fixed for the given tree. The main usage would be to introduce random terminal values.

final Random random = ...; final Op<Double> val = EphemeralConst.of(random::nextDouble);

Serialization Although the EphemeralConst class implements the Serializable interface, the serialization will fail if the const supplier is not serializable as well. This can be achieved by casting the supplier to a Serializable.

final Random random = new Random(); final EphemeralConst<Integer> object = EphemeralConst.of( "R", (Supplier<Integer> & Serializable)random::nextInt );

The serialization of the constant will fail, if the lambda has to capture variables form a non-serializable context (class). In such a case it is advisable to create a dedicated supplier class.

final class RandomInt implements Supplier<Integer>, Serializable { private final Random rnd = new Random(); private final int min; private final int max; private RandomInt(final int min, final int max) { this.min = min; this.max = max; } @Override public Integer get() { return rnd.nextInt(max - min) + min; } }

Since:

3.9

Version:

5.0

See Also:

Serialized Form

Method Summary

Modifier and Type	Method	Description
Op<T>	get()	Return a newly created, uninitialized constant of type T.
static <T> EphemeralConst<T>	of(String name, Supplier<T> supplier)	Create a new ephemeral constant with the given name and value supplier.
static <T> EphemeralConst<T>	of(Supplier<T> supplier)	Create a new ephemeral constant with the given value supplier.
String	toString()
T	value()	Fixes and returns the constant value.

Methods inherited from class io.jenetics.prog.op.Val

apply, arity, equals, hashCode, name

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.function.Function

andThen, apply, compose

Methods inherited from interface io.jenetics.prog.op.Op

arity, isTerminal, name

Method Detail

get

public Op<T> get()

Return a newly created, uninitialized constant of type T.

Specified by:

get in interface Op<T>

Specified by:

get in interface Supplier<T>

Returns:

a newly created, uninitialized constant of type T

See Also:

EphemeralConst

value

public T value()

Fixes and returns the constant value.

Specified by:

value in class Val<T>

Returns:

the constant value

Since:

5.0

toString

public String toString()

Overrides:

toString in class Object

of

public static <T> EphemeralConst<T> of(String name,
                                       Supplier<T> supplier)

Create a new ephemeral constant with the given name and value supplier. For every newly created operation tree, a new constant value is chosen for this terminal operation. The value is than kept constant for this tree.

Type Parameters:

T - the constant type

Parameters:

name - the name of the ephemeral constant

supplier - the value supplier

Returns:

a new ephemeral constant

Throws:

NullPointerException - if one of the arguments is null

of

public static <T> EphemeralConst<T> of(Supplier<T> supplier)

Create a new ephemeral constant with the given value supplier. For every newly created operation tree, a new constant value is chosen for this terminal operation. The value is than kept constant for this tree.

Type Parameters:

T - the constant type

Parameters:

supplier - the value supplier

Returns:

a new ephemeral constant

Throws:

NullPointerException - if the supplier is null