/*******************************************************************************
 * This file is part of the Polyglot extensible compiler framework.
 *
 * Copyright (c) 2000-2012 Polyglot project group, Cornell University
 * Copyright (c) 2006-2012 IBM Corporation
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * This program and the accompanying materials are made available under
 * the terms of the Lesser GNU Public License v2.0 which accompanies this
 * distribution.
 * 
 * The development of the Polyglot project has been supported by a
 * number of funding sources, including DARPA Contract F30602-99-1-0533,
 * monitored by USAF Rome Laboratory, ONR Grants N00014-01-1-0968 and
 * N00014-09-1-0652, NSF Grants CNS-0208642, CNS-0430161, CCF-0133302,
 * and CCF-1054172, AFRL Contract FA8650-10-C-7022, an Alfred P. Sloan 
 * Research Fellowship, and an Intel Research Ph.D. Fellowship.
 *
 * See README for contributors.
 ******************************************************************************/
package polyglot.ext.jl5.types;

import java.util.Map;
import java.util.Set;

import polyglot.types.Type;
import polyglot.types.TypeObject;

/**
 * An Annotations object represents annotations on an the annotations that should be
 * retained in the type information of a type object. This is a subset of the
 * annotations given on the type object's declaration. 
 * See JLS 3rd ed, 9.6.1.2, Retention.
 *
 */
public interface Annotations extends TypeObject {
    /**
     * The annotations that have been used.
     */
    Set<Type> annotationTypes();

    /**
     * The annotations that have
     * a retention policy of annotation.RetentionPolicy.CLASS or 
     * annotation.RetentionPolicy.RUNTIME.
     */
    Set<Type> retainedAnnotationTypes();

    /**
     * Get the element value pairs for the given annotation type.
     * Returns null if there is no annotation for the annotation type.
     */
    Map<String, AnnotationElementValue> elementValuePairs(Type annotationType);

    /**
     * Do these annotations contain an annotation of the specified type?
     * If this method returns true, then annotationType is in the set 
     * returned by this.annotationTypes().
     */
    boolean hasAnnotationType(Type annotationType);

    /**
     * If annotationType is a single element annotation type,
     * then return the element (or null if there is no
     * annotation for this annotation type).
     */
    AnnotationElementValue singleElement(Type annotationType);
}
