/*
 * Copyright 2015-2019 the original author or authors.
 *
 * All rights reserved. This program and the accompanying materials are
 * made available under the terms of the Eclipse Public License v2.0 which
 * accompanies this distribution and is available at
 *
 * http://www.eclipse.org/legal/epl-v20.html
 */

package org.junit.jupiter.api.extension;

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

import java.lang.annotation.Annotation;
import java.lang.reflect.Executable;
import java.lang.reflect.Parameter;
import java.util.List;
import java.util.Optional;

import org.apiguardian.api.API;

ParameterContext encapsulates the context in which an Executable will be invoked for a given Parameter.

A ParameterContext is used to support parameter resolution via a ParameterResolver.

See Also:
Since:5.0
/** * {@code ParameterContext} encapsulates the <em>context</em> in which an * {@link #getDeclaringExecutable Executable} will be invoked for a given * {@link #getParameter Parameter}. * * <p>A {@code ParameterContext} is used to support parameter resolution via * a {@link ParameterResolver}. * * @since 5.0 * @see ParameterResolver * @see java.lang.reflect.Parameter * @see java.lang.reflect.Executable * @see java.lang.reflect.Method * @see java.lang.reflect.Constructor */
@API(status = STABLE, since = "5.0") public interface ParameterContext {
Get the Parameter for this context.

WARNING

When searching for annotations on the parameter in this context, favor isAnnotated(Class<? extends Annotation>), findAnnotation(Class<Annotation>), and findRepeatableAnnotations(Class<Annotation>) over methods in the Parameter API due to a bug in javac on JDK versions prior to JDK 9.

See Also:
Returns:the parameter; never null
/** * Get the {@link Parameter} for this context. * * <h3>WARNING</h3> * <p>When searching for annotations on the parameter in this context, * favor {@link #isAnnotated(Class)}, {@link #findAnnotation(Class)}, and * {@link #findRepeatableAnnotations(Class)} over methods in the * {@link Parameter} API due to a bug in {@code javac} on JDK versions prior * to JDK 9. * * @return the parameter; never {@code null} * @see #getIndex() */
Parameter getParameter();
Get the index of the Parameter for this context within the parameter list of the Executable that declares the parameter.
See Also:
Returns:the index of the parameter
/** * Get the index of the {@link Parameter} for this context within the * parameter list of the {@link #getDeclaringExecutable Executable} that * declares the parameter. * * @return the index of the parameter * @see #getParameter() * @see Executable#getParameters() */
int getIndex();
Get the Executable (i.e., the Method or Constructor) that declares the Parameter for this context.
See Also:
Returns:the declaring Executable; never null
/** * Get the {@link Executable} (i.e., the {@link java.lang.reflect.Method} or * {@link java.lang.reflect.Constructor}) that declares the {@code Parameter} * for this context. * * @return the declaring {@code Executable}; never {@code null} * @see Parameter#getDeclaringExecutable() */
default Executable getDeclaringExecutable() { return getParameter().getDeclaringExecutable(); }
Get the target on which the Executable that declares the Parameter for this context will be invoked, if available.
Returns:an Optional containing the target on which the Executable will be invoked; never null but will be empty if the Executable is a constructor or a static method.
/** * Get the target on which the {@link #getDeclaringExecutable Executable} * that declares the {@link #getParameter Parameter} for this context will * be invoked, if available. * * @return an {@link Optional} containing the target on which the * {@code Executable} will be invoked; never {@code null} but will be * <em>empty</em> if the {@code Executable} is a constructor or a * {@code static} method. */
Optional<Object> getTarget();
Determine if an annotation of annotationType is either present or meta-present on the Parameter for this context.

WARNING

Favor the use of this method over directly invoking AnnotatedElement.isAnnotationPresent(Class<? extends Annotation>) due to a bug in javac on JDK versions prior to JDK 9.

Params:
  • annotationType – the annotation type to search for; never null
See Also:
Returns:true if the annotation is present or meta-present
Since:5.1.1
/** * Determine if an annotation of {@code annotationType} is either * <em>present</em> or <em>meta-present</em> on the {@link Parameter} for * this context. * * <h3>WARNING</h3> * <p>Favor the use of this method over directly invoking * {@link Parameter#isAnnotationPresent(Class)} due to a bug in {@code javac} * on JDK versions prior to JDK 9. * * @param annotationType the annotation type to search for; never {@code null} * @return {@code true} if the annotation is present or meta-present * @since 5.1.1 * @see #findAnnotation(Class) * @see #findRepeatableAnnotations(Class) */
boolean isAnnotated(Class<? extends Annotation> annotationType);
Find the first annotation of annotationType that is either present or meta-present on the Parameter for this context.

WARNING

Favor the use of this method over directly invoking annotation lookup methods in the Parameter API due to a bug in javac on JDK versions prior to JDK 9.

Params:
  • annotationType – the annotation type to search for; never null
Type parameters:
  • <A> – the annotation type
See Also:
Returns:an Optional containing the annotation; never null but potentially empty
Since:5.1.1
/** * Find the first annotation of {@code annotationType} that is either * <em>present</em> or <em>meta-present</em> on the {@link Parameter} for * this context. * * <h3>WARNING</h3> * <p>Favor the use of this method over directly invoking annotation lookup * methods in the {@link Parameter} API due to a bug in {@code javac} on JDK * versions prior to JDK 9. * * @param <A> the annotation type * @param annotationType the annotation type to search for; never {@code null} * @return an {@code Optional} containing the annotation; never {@code null} but * potentially empty * @since 5.1.1 * @see #isAnnotated(Class) * @see #findRepeatableAnnotations(Class) */
<A extends Annotation> Optional<A> findAnnotation(Class<A> annotationType);
Find all repeatable annotations of annotationType that are either present or meta-present on the Parameter for this context.

WARNING

Favor the use of this method over directly invoking annotation lookup methods in the Parameter API due to a bug in javac on JDK versions prior to JDK 9.

Params:
  • annotationType – the repeatable annotation type to search for; never null
Type parameters:
  • <A> – the annotation type
See Also:
Returns:the list of all such annotations found; neither null nor mutable, but potentially empty
Since:5.1.1
/** * Find all <em>repeatable</em> {@linkplain Annotation annotations} of * {@code annotationType} that are either <em>present</em> or * <em>meta-present</em> on the {@link Parameter} for this context. * * <h3>WARNING</h3> * <p>Favor the use of this method over directly invoking annotation lookup * methods in the {@link Parameter} API due to a bug in {@code javac} on JDK * versions prior to JDK 9. * * @param <A> the annotation type * @param annotationType the repeatable annotation type to search for; never * {@code null} * @return the list of all such annotations found; neither {@code null} nor * mutable, but potentially empty * @since 5.1.1 * @see #isAnnotated(Class) * @see #findAnnotation(Class) * @see java.lang.annotation.Repeatable */
<A extends Annotation> List<A> findRepeatableAnnotations(Class<A> annotationType); }