juneau-core/juneau-marshall/src/main/java/org/apache/juneau/MetaProvider.java

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// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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// ***************************************************************************************************************************
package org.apache.juneau;

import java.lang.annotation.*;
import java.lang.reflect.*;

/**
 * Parent interface for all class/method language-specific metadata providers.
 */
public interface MetaProvider {

	/**
	 * Default metadata provider.
	 */
	public static MetaProvider DEFAULT = new MetaProvider() {

		@Override /* MetaProvider */
		public <A extends Annotation> A getAnnotation(Class<A> a, Class<?> c) {
			return c.getAnnotation(a);
		}

		@Override /* MetaProvider */
		public <A extends Annotation> A getDeclaredAnnotation(Class<A> a, Class<?> c) {
			return c.getDeclaredAnnotation(a);
		}

		@Override /* MetaProvider */
		public <A extends Annotation> A getAnnotation(Class<A> a, Method m) {
			return m.getAnnotation(a);
		}

		@Override /* MetaProvider */
		public <A extends Annotation> A getAnnotation(Class<A> a, Field f) {
			return f.getAnnotation(a);
		}

		@Override /* MetaProvider */
		public <A extends Annotation> A getAnnotation(Class<A> a, Constructor<?> c) {
			return c.getAnnotation(a);
		}
	};

	/**
	 * Finds the specified annotation on the specified class.
	 *
	 * @param <A> The annotation type to find.
	 * @param a The annotation type to find.
	 * @param c The class to search on.
	 * @return The annotation, or <jk>null</jk> if not found.
	 */
	<A extends Annotation> A getAnnotation(Class<A> a, Class<?> c);

	/**
	 * Finds the specified declared annotation on the specified class.
	 *
	 * @param <A> The annotation type to find.
	 * @param a The annotation type to find.
	 * @param c The class to search on.
	 * @return The annotation, or <jk>null</jk> if not found.
	 */
	<A extends Annotation> A getDeclaredAnnotation(Class<A> a, Class<?> c);

	/**
	 * Finds the specified annotation on the specified method.
	 *
	 * @param <A> The annotation type to find.
	 * @param a The annotation type to find.
	 * @param m The method to search on.
	 * @return The annotation, or <jk>null</jk> if not found.
	 */
	<A extends Annotation> A getAnnotation(Class<A> a, Method m);

	/**
	 * Finds the specified annotation on the specified field.
	 *
	 * @param <A> The annotation type to find.
	 * @param a The annotation type to find.
	 * @param f The field to search on.
	 * @return The annotation, or <jk>null</jk> if not found.
	 */
	<A extends Annotation> A getAnnotation(Class<A> a, Field f);

	/**
	 * Finds the specified annotation on the specified constructor.
	 *
	 * @param <A> The annotation type to find.
	 * @param a The annotation type to find.
	 * @param c The constructor to search on.
	 * @return The annotation, or <jk>null</jk> if not found.
	 */
	<A extends Annotation> A getAnnotation(Class<A> a, Constructor<?> c);
}