001package org.junit.experimental.theories;
002
003import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
004import static java.lang.annotation.ElementType.PARAMETER;
005
006import java.lang.annotation.Retention;
007import java.lang.annotation.RetentionPolicy;
008import java.lang.annotation.Target;
009
010/**
011 * Annotating a {@link org.junit.experimental.theories.Theory Theory} method
012 * parameter with @ParametersSuppliedBy causes it to be supplied with
013 * values from the named
014 * {@link org.junit.experimental.theories.ParameterSupplier ParameterSupplier}
015 * when run as a theory by the {@link org.junit.experimental.theories.Theories
016 * Theories} runner.
017 * 
018 * In addition, annotations themselves can be annotated with
019 * @ParametersSuppliedBy, and then used similarly. ParameterSuppliedBy
020 * annotations on parameters are detected by searching up this hierarchy such
021 * that these act as syntactic sugar, making:
022 * 
023 * <pre>
024 * &#064;ParametersSuppliedBy(Supplier.class)
025 * public &#064;interface SpecialParameter { }
026 * 
027 * &#064;Theory
028 * public void theoryMethod(&#064;SpecialParameter String param) {
029 *   ...
030 * }
031 * </pre>
032 * 
033 * equivalent to:
034 * 
035 * <pre>
036 * &#064;Theory
037 * public void theoryMethod(&#064;ParametersSuppliedBy(Supplier.class) String param) {
038 *   ...
039 * }
040 * </pre>
041 */
042@Retention(RetentionPolicy.RUNTIME)
043@Target({ ANNOTATION_TYPE, PARAMETER })
044public @interface ParametersSuppliedBy {
045
046    Class<? extends ParameterSupplier> value();
047
048}