/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law
 * or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.apache.tools.ant.types;

import java.util.stream.Stream;

/**
 * Interface describing a collection of Resources.
 *
 * @since Ant 1.7
 */
public interface ResourceCollection extends Iterable<Resource> {

	/**
	 * Learn the number of contained Resources.
	 *
	 * @return number of elements as int.
	 */
	int size();

	/**
	 * Indicate whether this ResourceCollection is composed entirely of
	 * Resources accessible via local filesystem conventions. If true, all
	 * resources returned from this collection should respond with a
	 * {@link org.apache.tools.ant.types.resources.FileProvider} when asked via
	 * {@link Resource#as}.
	 *
	 * @return whether this is a filesystem-only resource collection.
	 */
	boolean isFilesystemOnly();

	/**
	 * Return a {@link Stream} over this {@link ResourceCollection}.
	 * @return {@link Stream} of {@link Resource}
	 * @since Ant 1.10.2
	 */
	default Stream<? extends Resource> stream() {
		final Stream.Builder<Resource> b = Stream.builder();
		forEach(b);
		return b.build();
	}

	/**
	 * Learn whether this {@link ResourceCollection} is empty.
	 * @return boolean
	 */
	default boolean isEmpty() {
	    return size() == 0;
	}
}