/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.text.source.projection;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.eclipse.jface.text.source.Annotation;

/**
 * A bag of annotations.
 * <p>
 * This class is not intended to be subclassed.
 * </p>
 *
 * @since 3.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public class AnnotationBag extends Annotation {

	private Set<Annotation> fAnnotations;

	/**
	 * Creates a new annotation bag.
	 *
	 * @param type the annotation type
	 */
	public AnnotationBag(String type) {
		super(type, false, null);
	}

	/**
	 * Adds the given annotation to the annotation bag.
	 *
	 * @param annotation the annotation to add
	 */
	public void add(Annotation annotation) {
		if (fAnnotations == null)
			fAnnotations= new HashSet<>(2);
		fAnnotations.add(annotation);
	}

	/**
	 * Removes the given annotation from the annotation bag.
	 *
	 * @param annotation the annotation to remove
	 */
	public void remove(Annotation annotation) {
		if (fAnnotations != null) {
			fAnnotations.remove(annotation);
			if (fAnnotations.isEmpty())
				fAnnotations= null;
		}
	}

	/**
	 * Returns whether the annotation bag is empty.
	 *
	 * @return <code>true</code> if the annotation bag is empty, <code>false</code> otherwise
	 */
	public boolean isEmpty() {
		return fAnnotations == null;
	}

	/**
	 * Returns an iterator for all annotation inside this
	 * annotation bag or <code>null</code> if the bag is empty.
	 *
	 * @return an iterator for all annotations in the bag or <code>null</code>
	 * @since 3.1
	 */
	public Iterator<Annotation> iterator() {
		if (!isEmpty())
			return fAnnotations.iterator();
		return null;
	}
}