/*
    * The SmartWeb Framework
    * Copyright (C) 2004-2006
    *
    * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * For further informations on the SmartWeb Framework please visit
   *
   *                        http://smartweb.sourceforge.net
   */
  package net.smartlab.web;
  
  import java.beans.Introspector;
  import java.beans.PropertyDescriptor;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.ServletRequest;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import net.smartlab.web.DataAccessObject.SearchInfo;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.struts.action.ActionForm;
  import org.apache.struts.action.ActionMapping;
  import org.apache.struts.action.DynaActionForm;
  import org.apache.struts.util.RequestUtils;
  
  
  /**
   * This is the base action for generic archive management. The class provides
   * template methods for common archive management operations and provides
   * support methods to handle common problems like multiple selections and search
   * criteria.
   * 
   * @author rlogiacco
   * @uml.dependency supplier="net.smartlab.web.EmptyMarkerTag"
   * @uml.dependency supplier="net.smartlab.web.Validator"
   */
  public abstract class AbstractArchiveAction extends DynaAction {
  
  	private final static Log LOGGER = LogFactory.getLog(AbstractArchiveAction.class);
  	/**
  	 * The standard name for a multiple selection request parameter.
  	 */
  	public final static String SELECTION = "selection";
  
  
  	/**
  	 * This action method should be invoked to list items matching a set of
  	 * specified criteria.
  	 * 
  	 * @param form the html form submitted with this request.
  	 * @param request the user request.
  	 * @param response the representation of the response channel.
  	 * @param mapping the system control mapping.
  	 * @return the name of a defined global or local forward.
  	 * @throws Exception if something unexpected happend during the request
  	 *         execution.
  	 */
  	public abstract String search(ActionForm form, HttpServletRequest request, HttpServletResponse response,
  			ActionMapping mapping) throws Exception;
  
  	/**
  	 * This action method should be invoked to retrieve a specific item.
  	 * 
  	 * @param form the html form submitted with this request.
  	 * @param request the user request.
  	 * @param response the representation of the response channel.
  	 * @param mapping the system control mapping.
  	 * @return the name of a defined global or local forward.
  	 * @throws Exception if something unexpected happend during the request
  	 *         execution.
  	 */
  	public abstract String select(ActionForm form, HttpServletRequest request, HttpServletResponse response,
  			ActionMapping mapping) throws Exception;
  
  	/**
  	 * This action method should be invoked to save or update an item.
  	 * 
  	 * @param form the html form submitted with this request.
  	 * @param request the user request.
  	 * @param response the representation of the response channel.
  	 * @param mapping the system control mapping.
 	 * @return the name of a defined global or local forward.
 	 * @throws Exception if something unexpected happend during the request
 	 *         execution.
 	 */
 	public abstract String update(ActionForm form, HttpServletRequest request, HttpServletResponse response,
 			ActionMapping mapping) throws Exception;
 
 	/**
 	 * This action method should be invoked to permanently remove an item.
 	 * 
 	 * @param form the html form submitted with this request.
 	 * @param request the user request.
 	 * @param response the representation of the response channel.
 	 * @param mapping the system control mapping.
 	 * @return the name of a defined global or local forward.
 	 * @throws Exception if something unexpected happend during the request
 	 *         execution.
 	 */
 	public abstract String remove(ActionForm form, HttpServletRequest request, HttpServletResponse response,
 			ActionMapping mapping) throws Exception;
 
 	/**
 	 * This action method should be invoked to permanently remove a set of
 	 * items.
 	 * 
 	 * @param form the html form submitted with this request.
 	 * @param request the user request.
 	 * @param response the representation of the response channel.
 	 * @param mapping the system control mapping.
 	 * @return the name of a defined global or local forward.
 	 * @throws Exception if something unexpected happend during the request
 	 *         execution.
 	 */
 	public abstract String removeAll(ActionForm form, HttpServletRequest request, HttpServletResponse response,
 			ActionMapping mapping) throws Exception;
 
 	/**
 	 * TODO documentation
 	 * 
 	 * @param request the user request.
 	 * @return
 	 */
 	public static String[] getListSelection(ServletRequest request) {
 		return request.getParameterValues("selection");
 	}
 
 	/**
 	 * TODO documentation
 	 * 
 	 * @param request the user request.
 	 * @param form
 	 * @param name
 	 * @return
 	 */
 	public static String[] getSelection(ActionForm form, String name) {
 		String[] values = null;
 		if (form instanceof DynaActionForm) {
 			values = (String[])((DynaActionForm)form).get(name);
 		} else {
 			try {
 				PropertyDescriptor[] descriptors = Introspector.getBeanInfo(form.getClass()).getPropertyDescriptors();
 				for (int i = 0; i < descriptors.length; i++) {
 					if (descriptors[i].getName().equals(name)) {
 						values = (String[])descriptors[i].getReadMethod().invoke(form, null);
 						break;
 					}
 				}
 			} catch (Exception e) {
 				LOGGER.warn("getSelection()", e);
 			}
 		}
 		if (values.length == 0) {
 			return null;
 		} else if (values.length == 1 && EmptyMarkerTag.EMPTY_MARKER.equals(values[0])) {
 			return new String[0];
 		} else {
 			List selection = new ArrayList();
 			for (int i = 0; i < values.length; i++) {
 				if (!EmptyMarkerTag.EMPTY_MARKER.equals(values[i])) {
 					selection.add(values[i]);
 				}
 			}
 			return (String[])selection.toArray(new String[selection.size()]);
 		}
 	}
 
 	/**
 	 * TODO documentation
 	 * 
 	 * @param form
 	 * @param name
 	 * @param values
 	 */
 	public static void setSelection(ActionForm form, String name, String[] values) {
 		if (form instanceof DynaActionForm) {
 			((DynaActionForm)form).set(name, values);
 		} else {
 			try {
 				PropertyDescriptor[] descriptors = Introspector.getBeanInfo(form.getClass()).getPropertyDescriptors();
 				for (int i = 0; i < descriptors.length; i++) {
 					if (descriptors[i].getName().equals(name)) {
 						Method setter = descriptors[i].getWriteMethod();
 						Class[] types = setter.getParameterTypes();
 						if (types.length == 1 && types[0].isArray() && types[0] == String.class) {
 							setter.invoke(form, values);
 							break;
 						}
 					}
 				}
 			} catch (Exception e) {
 				LOGGER.warn("getSelection()", e);
 			}
 		}
 	}
 
 	/**
 	 * TODO documentation
 	 * 
 	 * @param form
 	 * @param name
 	 */
 	public static void resetSelection(ActionForm form, String name) {
 		if (form instanceof DynaActionForm) {
 			((DynaActionForm)form).set(name, new String[0]);
 		} else {
 			try {
 				PropertyDescriptor[] descriptors = Introspector.getBeanInfo(form.getClass()).getPropertyDescriptors();
 				for (int i = 0; i < descriptors.length; i++) {
 					if (descriptors[i].getName().equals(name)) {
 						Method setter = descriptors[i].getWriteMethod();
 						Class[] types = setter.getParameterTypes();
 						if (types.length == 1 && types[0].isArray() && types[0] == String.class) {
 							setter.invoke(form, new String[0]);
 							break;
 						}
 					}
 				}
 			} catch (Exception e) {
 				LOGGER.warn("getSelection()", e);
 			}
 		}
 	}
 
 	/**
 	 * Parses the request searching for standard filtering and ordering
 	 * parameters.
 	 * 
 	 * @param request the received request.
 	 * @return filtering and ordering parameters.
 	 */
 	public static SearchInfo getSearchInfo(HttpServletRequest request) {
 		SearchInfo info = new SearchInfo();
 		info.setLocale(RequestUtils.getUserLocale(request, null));
 		info.setFilters(request.getParameterValues("filter"));
 		info.setUnion(request.getParameter("union"));
 		info.setOrder(request.getParameter("order"));
 		return info;
 	}
 }