PageTagSupport.java

/*
 *  Pager Tag Library
 *
 *  Copyright (C) 2002  James Klicman <james@jsptags.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package com.frameworkset.common.tag.pager.tags;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.PageContext;

import com.frameworkset.common.tag.pager.parser.PageTagExport;
import com.frameworkset.common.tag.pager.parser.ParseException;
import com.frameworkset.common.tag.pager.parser.TagExportParser;

public abstract class PageTagSupport extends PagerTagSupport {

	private String export = null;

	private PageTagExport pageTagExport = null;
	private Object oldPageUrl = null;
	private Object oldPageNumber = null;
	private Object oldFirstItem = null;
	private Object oldLastItem = null;


	public final void setExport(String value) throws JspException {
		if (export != value) {
			try {
				pageTagExport = TagExportParser.parsePageTagExport(value);
			} catch (ParseException ex) {
				throw new JspTagException(ex.getMessage());
			}
		}
		export = value;
	}

	public final String getExport() {
		return export;
	}


	protected final void setPageAttributes(long page) {
		if (pageTagExport == null) {
			pageContext.setAttribute(PageTagExport.PAGE_URL,
					pagerContext.getPageUrl(page));
			pageContext.setAttribute(PageTagExport.PAGE_NUMBER,
					pagerContext.getPageNumber(page));
		} else {
			String name;

			if ((name = pageTagExport.getPageUrl()) != null)
				pageContext.setAttribute(name, pagerContext.getPageUrl(page));

			if ((name = pageTagExport.getPageNumber()) != null)
				pageContext.setAttribute(name, pagerContext.getPageNumber(page));

			int maxPageItems = pagerContext.getMaxPageItems();

			if ((name = pageTagExport.getFirstItem()) != null) {
				long firstItem = (page * maxPageItems) + 1;
				pageContext.setAttribute(name, new Long(firstItem));
			}

			if ((name = pageTagExport.getLastItem()) != null) {
				long lastItem = Math.min((page + 1) * maxPageItems,
						pagerContext.getItemCount());
				pageContext.setAttribute(name, new Long(lastItem));
			}
		}
	}

	protected final void setOffsetAttributes(long offset) {
		if (pageTagExport == null) {
			pageContext.setAttribute(PageTagExport.PAGE_URL,
					pagerContext.getOffsetUrl(offset,pagerContext.getSortKey(),pagerContext.getDesc()));
			pageContext.setAttribute(PageTagExport.PAGE_NUMBER,
					pagerContext.getOffsetPageNumber(offset));
		} else {
			String name;

			if ((name = pageTagExport.getPageUrl()) != null)
				pageContext.setAttribute(name, pagerContext.getOffsetUrl(offset,pagerContext.getSortKey(),pagerContext.getDesc()));

			if ((name = pageTagExport.getPageNumber()) != null)
				pageContext.setAttribute(name,
						pagerContext.getOffsetPageNumber(offset));

			int maxPageItems = pagerContext.getMaxPageItems();

			if ((name = pageTagExport.getFirstItem()) != null) {
				long firstItem = offset + 1;
				pageContext.setAttribute(name, new Long(firstItem));
			}

			if ((name = pageTagExport.getLastItem()) != null) {
				long lastItem = Math.min(offset + maxPageItems,
						pagerContext.getItemCount());
				pageContext.setAttribute(name, new Long(lastItem));
			}
		}
	}


	protected final void removeAttributes() {
		if (pageTagExport == null) {
			pageContext.removeAttribute(PageTagExport.PAGE_URL,PageContext.PAGE_SCOPE);
			pageContext.removeAttribute(PageTagExport.PAGE_NUMBER,PageContext.PAGE_SCOPE);
		} else {
			String name;

			if ((name = pageTagExport.getPageUrl()) != null)
				pageContext.removeAttribute(name,PageContext.PAGE_SCOPE);

			if ((name = pageTagExport.getPageNumber()) != null)
				pageContext.removeAttribute(name,PageContext.PAGE_SCOPE);

			if ((name = pageTagExport.getFirstItem()) != null)
				pageContext.removeAttribute(name,PageContext.PAGE_SCOPE);

			if ((name = pageTagExport.getLastItem()) != null)
				pageContext.removeAttribute(name,PageContext.PAGE_SCOPE);
		}
	}

	public int doStartTag() throws JspException {
		super.doStartTag();

		if (pageTagExport == null) {
			oldPageUrl = pageContext.getAttribute(PageTagExport.PAGE_URL);
			oldPageNumber = pageContext.getAttribute(PageTagExport.PAGE_NUMBER);
		} else {
			String name;

			if ((name = pageTagExport.getPageUrl()) != null)
				oldPageUrl = pageContext.getAttribute(name);

			if ((name = pageTagExport.getPageNumber()) != null)
				oldPageNumber = pageContext.getAttribute(name);

			if ((name = pageTagExport.getFirstItem()) != null)
				oldFirstItem = pageContext.getAttribute(name);

			if ((name = pageTagExport.getLastItem()) != null)
				oldLastItem = pageContext.getAttribute(name);
		}

		return EVAL_BODY_INCLUDE;
	}

	public int doEndTag() throws JspException {

		if (pageTagExport == null) {
			restoreAttribute(PageTagExport.PAGE_URL, oldPageUrl);
			restoreAttribute(PageTagExport.PAGE_NUMBER, oldPageNumber);
			oldPageUrl = null;
			oldPageNumber = null;
		} else {
			String name;

			if ((name = pageTagExport.getPageUrl()) != null) {
				restoreAttribute(name, oldPageUrl);
				oldPageUrl = null;
			}

			if ((name = pageTagExport.getPageNumber()) != null) {
				restoreAttribute(name, oldPageNumber);
				oldPageNumber = null;
			}

			if ((name = pageTagExport.getFirstItem()) != null) {
				restoreAttribute(name, oldFirstItem);
				oldFirstItem = null;
			}

			if ((name = pageTagExport.getLastItem()) != null) {
				restoreAttribute(name, oldLastItem);
				oldLastItem = null;
			}
		}

		super.doEndTag();

		return EVAL_PAGE;
	}

	public void release() {
		export = null;
		pageTagExport = null;
		oldPageUrl = null;
		oldPageNumber = null;
		oldFirstItem = null;
		oldLastItem = null;
		super.release();
	}
}

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