HtmlSortHeaderRenderer.java

/**********************************************************************************
*
* $Id: HtmlSortHeaderRenderer.java 105079 2012-02-24 23:08:11Z ottenhoff@longsight.com $
*
***********************************************************************************
*
 * Copyright (c) 2005, 2006, 2007, 2008 The Sakai Foundation, The MIT Corporation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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.
*
**********************************************************************************/

/*
 * Based very slightly on org.apache.myfaces.custom.sortheader.HtmlSortHeaderRenderer.
 * (Only about a half-dozen lines of code are in common.)
 *
 * The original file's license header is below.
 */

/*
 * Copyright 2004 The Apache Software Foundation.
 *
 * 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.
 */

package org.sakaiproject.tool.gradebook.jsf;

import java.io.IOException;

import javax.faces.component.UIComponent;
import javax.faces.component.html.HtmlGraphicImage;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.myfaces.component.UserRoleUtils;
import org.apache.myfaces.component.html.ext.HtmlDataTable;
import org.apache.myfaces.custom.sortheader.HtmlCommandSortHeader;
import org.apache.myfaces.shared_impl.renderkit.html.HTML;
import org.apache.myfaces.shared_impl.renderkit.html.HtmlLinkRendererBase;

/**
 * Based on org.apache.myfaces.custom.sortheader.HtmlSortHeaderRenderer.
 * Modified to better distinguish the current sort column and to use an image file
 * to indicate direction.
 *
 * @author <a href="mailto:jholtzman@berkeley.edu">Josh Holtzman </a>
 */
public class HtmlSortHeaderRenderer extends HtmlLinkRendererBase {
	private static final Log log = LogFactory
			.getLog(HtmlSortHeaderRenderer.class);
	public final static String CURRENT_SORT_STYLE = "currentSort";
	public final static String NOT_CURRENT_SORT_STYLE = "notCurrentSort";

	public void encodeBegin(FacesContext facesContext, UIComponent component)
			throws IOException {
		// If this is a currently sorted sort header, always give it the "currentSort" CSS style class
        if (component instanceof HtmlCommandSortHeader) {
            HtmlCommandSortHeader sortHeader = (HtmlCommandSortHeader)component;
            String styleClass = StringUtils.trimToNull(getStyleClass(facesContext, component));
            String newStyleClass;
            String unStyleClass;
            if (sortHeader.findParentDataTable().getSortColumn().equals(sortHeader.getColumnName())) {
            	newStyleClass = CURRENT_SORT_STYLE;
            	unStyleClass = NOT_CURRENT_SORT_STYLE;
            } else {
            	newStyleClass = NOT_CURRENT_SORT_STYLE;
            	unStyleClass = CURRENT_SORT_STYLE;
            }
            if (StringUtils.indexOf(styleClass, newStyleClass) == -1) {
            	if (StringUtils.indexOf(styleClass, unStyleClass) != -1) {
            		styleClass = StringUtils.replace(styleClass, unStyleClass, newStyleClass);
            	} else if (styleClass != null) {
            		styleClass = (new StringBuilder(styleClass)).append(' ').append(newStyleClass).toString();
            	} else {
            		styleClass = newStyleClass;
            	}
            	sortHeader.setStyleClass(styleClass);
            }
        }
 		super.encodeBegin(facesContext, component); //check for NP
	}

	public void encodeEnd(FacesContext facesContext, UIComponent component)
			throws IOException {
		if (log.isDebugEnabled()) log.debug("encodeEnd rendering " + component);
		if (!UserRoleUtils.isEnabledOnUserRole(component)) {
            super.encodeEnd(facesContext, component);
        } else {
			HtmlCommandSortHeader sortHeader = (HtmlCommandSortHeader) component;
			HtmlDataTable dataTable = sortHeader.findParentDataTable();

			if (sortHeader.isArrow() && sortHeader.getColumnName().equals(dataTable.getSortColumn())) {
				ResponseWriter writer = facesContext.getResponseWriter();

                writer.write(HTML.NBSP_ENTITY);

                HtmlGraphicImage image = new HtmlGraphicImage();
                String path = facesContext.getExternalContext().getRequestContextPath();
                if (dataTable.isSortAscending()) {
                    image.setValue(path + "/images/sortascending.gif");
				} else {
                    image.setValue(path + "/images/sortdescending.gif");
				}

                writer.startElement(HTML.IMG_ELEM, image);
                writer.writeURIAttribute("src", image.getValue(), null);
                writer.endElement(HTML.IMG_ELEM);
			}
            super.encodeEnd(facesContext, component);
		}
	}
}