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Jqwik API module
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package net.jqwik.api.state;

import java.util.function.*;

import org.apiguardian.api.*;

import net.jqwik.api.*;

import org.jspecify.annotations.*;

import static org.apiguardian.api.API.Status.*;

/**
 * A transformation provides an arbitrary of {@linkplain Transformer transformers}
 * for values of type {@code T} in the context of {@linkplain Chain chains}.
 * The provided arbitrary of transformers can depend on the previous state,
 * which can be retrieved using the first {@linkplain Supplier supplier} argument of the function.
 * A transformation can also be restricted by a precondition,
 * which must hold for the transformation to be applicable.
 *
 * @param  The type of state to be transformed in a chain
 * @see Chain
 * @see Transformer
 */
@FunctionalInterface
@API(status = EXPERIMENTAL, since = "1.7.0")
public interface Transformation extends Function, Arbitrary>> {

	Predicate NO_PRECONDITION = ignore -> false;

	class Builder {
		final private Predicate precondition;

		private Builder(Predicate precondition) {
			this.precondition = precondition;
		}

		public Transformation provide(Arbitrary> arbitrary) {
			return new Transformation() {
				@Override
				public Predicate precondition() {
					return precondition;
				}

				@Override
				public Arbitrary> apply(Supplier ignore) {
					return arbitrary;
				}
			};
		}

		public Transformation provide(Function>> arbitraryCreator) {
			return new Transformation() {
				@Override
				public Predicate precondition() {
					return precondition;
				}

				@Override
				public Arbitrary> apply(Supplier supplier) {
					return arbitraryCreator.apply(supplier.get());
				}
			};
		}
	}

	/**
	 * Create a TransformerProvider with a precondition
	 */
	static  Builder when(Predicate precondition) {
		return new Builder(precondition);
	}

	/**
	 * Override this method if the applicability of the provided transformers depends on the previous state
	 *
	 * @return a predicate with input {@code T}
	 */
	@SuppressWarnings("unchecked")
	default Predicate precondition() {
		return (Predicate) NO_PRECONDITION;
	}
}