EPTagBrowseController.java

/**
 * <a href="http://www.openolat.org">
 * OpenOLAT - Online Learning and Training</a><br>
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); <br>
 * you may not use this file except in compliance with the License.<br>
 * You may obtain a copy of the License at the
 * <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache homepage</a>
 * <p>
 * Unless required by applicable law or agreed to in writing,<br>
 * software distributed under the License is distributed on an "AS IS" BASIS, <br>
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
 * See the License for the specific language governing permissions and <br>
 * limitations under the License.
 * <p>
 * Initial code contributed and copyrighted by<br>
 * frentix GmbH, http://www.frentix.com
 * <p>
 */
package org.olat.portfolio.ui.artefacts.view;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.olat.core.gui.UserRequest;
import org.olat.core.gui.components.Component;
import org.olat.core.gui.components.link.Link;
import org.olat.core.gui.components.link.LinkFactory;
import org.olat.core.gui.components.velocity.VelocityContainer;
import org.olat.core.gui.control.Event;
import org.olat.core.gui.control.WindowControl;
import org.olat.core.gui.control.controller.BasicController;
import org.olat.core.util.StringHelper;
import org.olat.portfolio.manager.EPArtefactTagCloud;
import org.olat.portfolio.manager.EPFrontendManager;
import org.olat.portfolio.model.artefacts.AbstractArtefact;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * Description:<br>
 * a recursive tag-browser showing a tag-tree
 * the deeper you go in, the less common tags of available resources are shown
 * 
 * <P>
 * Initial Date: 10.11.2010 <br>
 * 
 * @author Roman Haag, roman.haag@frentix.com, http://www.frentix.com
 */
public class EPTagBrowseController extends BasicController {
	
	private String activeCSS = "tag label label-info on";
	private String inactiveCSS = "tag label label-info";
	private String disabledCSS = "tag label label-info";

	@Autowired
	private EPFrontendManager ePFMgr;
	private final List<Link> tagLinks = new ArrayList<Link>();
	private List<AbstractArtefact> allUsersArtefacts;

	public EPTagBrowseController(UserRequest ureq, WindowControl wControl) {
		super(ureq, wControl);
		VelocityContainer mainVc = createVelocityContainer("tagbrowser");
		
		List<String> tagList = ePFMgr.getUsersTagsOfArtefactType(getIdentity());
		int count = 0;
		List<String> realTags = getRealArtefactTags();
		for(String tag:tagList) {
			if (realTags.contains(tag)){
				String id = "tag_" + count++;
				Link tagLink = LinkFactory.createLink(id, mainVc, this);
				tagLink.setCustomEnabledLinkCSS(inactiveCSS);
				tagLink.setCustomDisplayText(StringHelper.escapeHtml(tag));
				tagLink.setCustomDisabledLinkCSS(disabledCSS);
				tagLink.setUserObject(new TagWrapper(tag));
				tagLinks.add(tagLink);
			}
		}
		mainVc.contextPut("tags", tagLinks);
		putInitialPanel(mainVc);
	}
	
	// filter available tags for such of non-existing artefacts
	private List<String> getRealArtefactTags(){
		allUsersArtefacts = ePFMgr.getArtefactPoolForUser(getIdentity());
		if (allUsersArtefacts == null) return new ArrayList<String>();
		HashSet<String> realTags = new HashSet<String>();
		for (AbstractArtefact abstractArtefact : allUsersArtefacts) {
			List<String> thisTags = ePFMgr.getArtefactTags(abstractArtefact);
			realTags.addAll(thisTags);
		}
		List<String> res = new ArrayList<String>();
		res.addAll(realTags);
		return res;
	}
	
	/**
	 * @see org.olat.core.gui.control.DefaultController#event(org.olat.core.gui.UserRequest,
	 *      org.olat.core.gui.components.Component,
	 *      org.olat.core.gui.control.Event)
	 */
	@Override
	protected void event(UserRequest ureq, Component source, Event event) {
		// nothing
		if(tagLinks.contains(source)) {
			Link tagLink = (Link)source;
			TagWrapper tagWrapper = (TagWrapper)tagLink.getUserObject();
			if(TagState.possible.equals(tagWrapper.getState())) {
				tagWrapper.setState(TagState.selected);
				List<AbstractArtefact> artefacts = recalculateTagCloud();
				fireEvent(ureq, new EPTagBrowseEvent(artefacts));
			} else if(TagState.selected.equals(tagWrapper.getState())) {
				tagWrapper.setState(TagState.possible);
				List<AbstractArtefact> artefacts = recalculateTagCloud();
				fireEvent(ureq, new EPTagBrowseEvent(artefacts));
			}
		}
	}

	/**
	 * @see org.olat.core.gui.control.DefaultController#doDispose()
	 */
	@Override
	protected void doDispose() {
		tagLinks.clear();
	}
	
	private List<AbstractArtefact> recalculateTagCloud() {
		List<String> selectedTags = getSelectedTags();
		if(selectedTags.isEmpty()) {
			for(Link tagLink:tagLinks) {
				TagWrapper tagWrapper = (TagWrapper)tagLink.getUserObject();
				tagLink.setCustomEnabledLinkCSS(inactiveCSS);
				tagLink.setEnabled(true);
				tagWrapper.setState(TagState.possible);
			}
			return allUsersArtefacts;
		}

		EPArtefactTagCloud artefactsAndTags = ePFMgr.getArtefactsAndTagCloud(getIdentity(), selectedTags);
		List<AbstractArtefact> filteredArtefacts = artefactsAndTags.getArtefacts();
		Set<String> newTags = artefactsAndTags.getTags();

		if(newTags != null && !newTags.isEmpty()) {
			for(Link tagLink:tagLinks) {
				TagWrapper tagWrapper = (TagWrapper)tagLink.getUserObject();
				String tag = tagWrapper.getTag();
				switch(tagWrapper.getState()) {
					case selected:
						tagLink.setCustomEnabledLinkCSS(activeCSS);
						tagLink.setEnabled(true);
						break;
					case possible:
						if(!newTags.contains(tag)) {
							tagWrapper.setState(TagState.unpossible);
							tagLink.setEnabled(false);
						} else {
							tagLink.setCustomEnabledLinkCSS(inactiveCSS);
							tagLink.setEnabled(true);
						}
						break;
					case unpossible:
						if(newTags.contains(tag)) {
							tagWrapper.setState(TagState.possible);
							tagLink.setCustomEnabledLinkCSS(inactiveCSS);
							tagLink.setEnabled(true);
						} else {
							tagLink.setEnabled(false);
						}
						break;
				}
			}
		}
		
		return filteredArtefacts;
	}
	
	private List<String> getSelectedTags() {
		List<String> tags = new ArrayList<String>();
		for(Link tagLink:tagLinks) {
			TagWrapper tagWrapper = (TagWrapper)tagLink.getUserObject();
			if(TagState.selected.equals(tagWrapper.getState())) {
				tags.add(tagWrapper.getTag());
			}
		}
		return tags;
	}
	
	private class TagWrapper {
		private final String tag;
		private TagState state;
		
		public TagWrapper(String tag) {
			this.tag = tag;
			state = TagState.possible;
		}

		public TagState getState() {
			return state;
		}

		public void setState(TagState state) {
			this.state = state;
		}

		public String getTag() {
			return tag;
		}
	}
	
	private enum TagState {
		selected,
		possible,
		unpossible
	}
}