PaginatedResult.java

/*

   Copyright 2011 Monits
 
   Licensed 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.

*/



/**
 * PaginatedResult Class
 *
 * @copyright 2011 Monits
 * @license   Apache 2.0 License
 * @version   Release: 1.0.0
 * @link      http://www.monits.com/
 * @since     1.0.0
 */
package com.monits.commons;

import java.util.Collections;
import java.util.List;

/**
 * PaginatedResult Class
 *
 * @author    José Manuel Rolón<jmrolon@monits.com>
 * @copyright 2011 Monits
 * @license   Apache 2.0 License
 * @version   Release: 1.0.0
 * @link      http://www.monits.com/
 * @since     1.0.0
 */
public class PaginatedResult<T> {

	private final long actualPage;

	private final long totalPage;

	private final List<T> elements;

	private final long totalElements;

	 /**
	 * Basic constructor with all fields.
	 *
	 * @param actualPage The Selected page
	 * @param elements The items in the selected page
	 * @param totalElements the total amount of elements
	 * @param amountPerPage the amount the elements per page
	 */
	public PaginatedResult(final int actualPage, final List<T> elements,
			final long totalElements, final long amountPerPage) {
		super();

		this.actualPage = actualPage;
		this.totalPage = calculateTotalPages(totalElements, amountPerPage);
		this.elements = Collections.unmodifiableList(elements);
		this.totalElements = totalElements;
	}

	/**
	 * @return the acutalPage
	 */
	public long getActualPage() {
		return actualPage;
	}

	/**
	 * @return the totalPage
	 */
	public long getTotalPage() {
		return totalPage;
	}

	/**
	 * @return the elements
	 */
	public List<T> getElements() {
		return elements;
	}

	/**
	 * @return the totalElements
	 */
	public long getTotalElements() {
		return totalElements;
	}

	/**
     * Calculate the total amount of pages, using a amount of elements and the amount of elements per page
     *
     * @param totalElements amount of total elements
     * @param amountPage amount of element per page
     * @return the total amount of pages
     */
	private long calculateTotalPages(final long totalElements, final long amountPage) {

		long totalPages;

		totalPages = totalElements / amountPage;

		if (totalElements % amountPage != 0) {
			totalPages++;
		}
		return totalPages;
	}

}