PaginatedResult.java

/*
 * Copyright (c) 2010, the Last.fm Java Project and Committers
 * All rights reserved.
 *
 * Redistribution and use of this software in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above
 *   copyright notice, this list of conditions and the
 *   following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the
 *   following disclaimer in the documentation and/or other
 *   materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package de.umass.lastfm;

import java.util.Collection;

/**
 * A <code>PaginatedResult</code> is returned by methods which result set might be so large that it needs
 * to be paginated. Each <code>PaginatedResult</code> contains the total number of result pages, the current
 * page and a <code>Collection</code> of entries for the current page.
 *
 * @author Janni Kovacs
 */
public class PaginatedResult<T> {

	private int page;
	private int totalPages;
	private Collection<T> pageResults;

	PaginatedResult(int page, int totalPages, Collection<T> pageResults) {
		this.page = page;
		this.totalPages = totalPages;
		this.pageResults = pageResults;
	}

	/**
	 * Returns the page number of this result.
	 *
	 * @return page number
	 */
	public int getPage() {
		return page;
	}

	/**
	 * Returns a list of entries of the type <code>T</code> for this page.
	 *
	 * @return page results
	 */
	public Collection<T> getPageResults() {
		return pageResults;
	}

	/**
	 * Returns the total number of pages available.
	 *
	 * @return total pages
	 */
	public int getTotalPages() {
		return totalPages;
	}

	/**
	 * Returns <code>true</code> if this Result contains no elements, which is the case for service calls that would have returned a
	 * <code>PaginatedResult</code> but fail.
	 *
	 * @return <code>true</code> if this result contains no elements
	 */
	public boolean isEmpty() {
		return pageResults == null || pageResults.isEmpty();
	}
}