import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

/**
 * 分頁資訊 第一頁從1開始
 * 
 */
public class Page<T> implements Serializable, Iterable<T> {

	protected List<T> result;

	protected int pageSize=10;

	protected int pageNumber=1;

	/**
	 * 總記錄數
	 */
	protected long totalCount = 0;
	
	protected boolean isPagination = true;
	
	private int pageNum;//總頁數

	private int startIndex;

	private int limit;

	public int getPageNum() {
	    int  totalPageNum = (int) ((totalCount % pageSize == 0) ? totalCount / pageSize : totalCount / pageSize + 1);
		return totalPageNum;
	}
	
	public Page() {

	}

	public Page(int pageNumber, int pageSize, long totalCount) {
		this(pageNumber, pageSize, totalCount, new ArrayList(0));
	}

	public Page(int pageNumber, int pageSize, long totalCount, List<T> result) {
		if (pageSize <= 0)
			throw new IllegalArgumentException("[pageSize] must great than zero");
		this.pageSize = pageSize;
		this.pageNumber = PageUtils.computePageNumber(pageNumber, pageSize, totalCount);
		this.totalCount = totalCount;
		setResult(result);
	}

	public void setResult(List<T> elements) {
		if (elements == null)
			throw new IllegalArgumentException("'result' must be not null");
		this.result = elements;
	}

	/**
	 * 當前頁包含的資料
	 * 
	 * @return 當前頁資料來源
	 */
	public List<T> getResult() {
		return result;
	}

	/**
	 * 是否是首頁（第一頁），第一頁頁碼為1
	 * 
	 * @return 首頁標識
	 */
	public boolean isFirstPage() {
		return getThisPageNumber() == 1;
	}

	/**
	 * 是否是最後一頁
	 * 
	 * @return 末頁標識
	 */
	public boolean isLastPage() {
		return getThisPageNumber() >= getLastPageNumber();
	}

	/**
	 * 是否有下一頁
	 * 
	 * @return 下一頁標識
	 */
	public boolean isHasNextPage() {
		return getLastPageNumber() > getThisPageNumber();
	}

	/**
	 * 是否有上一頁
	 * 
	 * @return 上一頁標識
	 */
	public boolean isHasPreviousPage() {
		return getThisPageNumber() > 1;
	}

	/**
	 * 獲取最後一頁頁碼，也就是總頁數
	 * 
	 * @return 最後一頁頁碼
	 */
	public int getLastPageNumber() {
		return PageUtils.computeLastPageNumber(totalCount, pageSize);
	}

	/**
	 * 總的資料條目數量，0表示沒有資料
	 * 
	 * @return 總數量
	 */
	public long getTotalCount() {
		return totalCount;
	}

	public void setTotalCount(long totalCount) {
		this.totalCount = totalCount;
	}

	/**
	 * 獲取當前頁的首條資料的行編碼
	 * 
	 * @return 當前頁的首條資料的行編碼
	 */
	public int getThisPageFirstElementNumber() {
		return (getThisPageNumber() - 1) * getPageSize() + 1;
	}

	/**
	 * 獲取當前頁的末條資料的行編碼
	 * 
	 * @return 當前頁的末條資料的行編碼
	 */
	public long getThisPageLastElementNumber() {
		int fullPage = getThisPageFirstElementNumber() + getPageSize() - 1;
		return getTotalCount() < fullPage ? getTotalCount() : fullPage;
	}

	/**
	 * 獲取下一頁編碼
	 * 
	 * @return 下一頁編碼
	 */
	public int getNextPageNumber() {
		return getThisPageNumber() + 1;
	}

	/**
	 * 獲取上一頁編碼
	 * 
	 * @return 上一頁編碼
	 */
	public int getPreviousPageNumber() {
		return getThisPageNumber() - 1;
	}

	/**
	 * 每一頁顯示的條目數
	 * 
	 * @return 每一頁顯示的條目數
	 */
	public int getPageSize() {
		return pageSize;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

	/**
	 * 當前頁的頁碼
	 * 
	 * @return 當前頁的頁碼
	 */
	public int getThisPageNumber() {
		return pageNumber;
	}

	public void setPageNumber(int pageNumber) {
		this.pageNumber = pageNumber;
	}

	/**
	 * 得到用於多頁跳轉的頁碼
	 * 
	 * @return
	 */
	public List<Integer> getLinkPageNumbers() {
		return PageUtils.generateLinkPageNumbers(getThisPageNumber(), getLastPageNumber(), 10);
	}

	/**
	 * 得到資料庫的第一條記錄號
	 * 
	 * @return
	 */
	public int getFirstResult() {
		return PageUtils.getFirstResult(pageNumber, pageSize);
	}

	public Iterator<T> iterator() {
		return (Iterator<T>) (result == null ? Collections.emptyList().iterator() : result.iterator());
	}

	public boolean isPagination() {
		return isPagination;
	}

	public void setPagination(boolean isPagination) {
		this.isPagination = isPagination;
	}
}
 

import java.util.List;

public class PageUtils {

	private PageUtils() {
	}

	public static int getFirstResult(int pageNumber, int pageSize) {
		if (pageSize <= 0)
			throw new IllegalArgumentException("[pageSize] must great than zero");
		return (pageNumber - 1) * pageSize;
	}

	public static List<Integer> generateLinkPageNumbers(int currentPageNumber, int lastPageNumber, int count) {
		int avg = count / 2;

		int startPageNumber = currentPageNumber - avg;
		if (startPageNumber <= 0) {
			startPageNumber = 1;
		}

		int endPageNumber = startPageNumber + count - 1;
		if (endPageNumber > lastPageNumber) {
			endPageNumber = lastPageNumber;
		}

		if (endPageNumber - startPageNumber < count) {
			startPageNumber = endPageNumber - count;
			if (startPageNumber <= 0) {
				startPageNumber = 1;
			}
		}

		java.util.List<Integer> result = new java.util.ArrayList();
		for (int i = startPageNumber; i <= endPageNumber; i++) {
			result.add(new Integer(i));
		}
		return result;
	}

	public static int computeLastPageNumber(long totalElements, int pageSize) {
		int result = (int) (totalElements % pageSize == 0 ? totalElements / pageSize : totalElements / pageSize + 1);
		if (result <= 1)
			result = 1;
		return result;
	}

	public static int computePageNumber(int pageNumber, int pageSize, long totalElements) {
		if (pageNumber <= 1) {
			return 1;
		}
		if (Integer.MAX_VALUE == pageNumber || pageNumber > computeLastPageNumber(totalElements, pageSize)) { // last page
			return computeLastPageNumber(totalElements, pageSize);
		}
		return pageNumber;
	}
}