OO-3455: allow feedback with only an image, a video or a math formula

src/main/java/org/olat/ims/qti21/model/xml/TestFeedbackBuilder.java

@@ -19,9 +19,18 @@
  */
 package org.olat.ims.qti21.model.xml;
 
+import java.io.StringReader;
 import java.util.List;
 
+import org.cyberneko.html.parsers.SAXParser;
+import org.olat.core.logging.OLog;
+import org.olat.core.logging.Tracing;
+import org.olat.core.util.StringHelper;
+import org.olat.core.util.filter.FilterFactory;
 import org.olat.ims.qti21.QTI21Constants;
+import org.xml.sax.Attributes;
+import org.xml.sax.InputSource;
+import org.xml.sax.helpers.DefaultHandler;
 
 import uk.ac.ed.ph.jqtiplus.node.expression.Expression;
 import uk.ac.ed.ph.jqtiplus.node.expression.general.BaseValue;
@@ -48,6 +57,8 @@ import uk.ac.ed.ph.jqtiplus.value.SingleValue;
  */
 public class TestFeedbackBuilder {
 	
+	private static final OLog log = Tracing.createLoggerFor(TestFeedbackBuilder.class);
+	
 	private final TestFeedback testFeedback;
 	private final AssessmentTest assessmentTest;
 	
@@ -74,8 +85,7 @@ public class TestFeedbackBuilder {
 	}
 	
 	public OutcomeRule getResponseRule() {
-		OutcomeRule feedbackRule = findFeedbackRule(testFeedback.getOutcomeValue());
-		return feedbackRule;
+		return findFeedbackRule(testFeedback.getOutcomeValue());
 	}
 	
 	public boolean isPassedRule() {
@@ -210,4 +220,51 @@ public class TestFeedbackBuilder {
 		}
 		return false;
 	}
+	
+	/**
+	 * 
+	 * @param value The content of the feedback.
+	 * @return
+	 */
+	public static boolean isEmpty(String value) {
+		if(!StringHelper.containsNonWhitespace(value)) {
+			return true;
+		}
+		if(StringHelper.containsNonWhitespace(FilterFactory.getHtmlTagsFilter().filter(value))) {
+			return false;
+		}
+		
+		try {
+			SAXParser parser = new SAXParser();
+			HTMLHandler contentHandler = new HTMLHandler();
+			parser.setContentHandler(contentHandler);
+			parser.parse(new InputSource(new StringReader(value)));
+			return !contentHandler.hasRelevantTags();
+		} catch (Exception e) {
+			log.error("", e);
+		}
+		return true;
+	}
+	
+	private static class HTMLHandler extends DefaultHandler {
+
+		private int count = 0;
+		
+		public boolean hasRelevantTags() {
+			return count > 0;
+		}
+
+		@Override
+		public void startElement(String uri, String localName, String qName, Attributes attributes) {
+			String elem = localName.toLowerCase();
+			if("img".equals(elem)) {
+				count++;
+			} else if("span".equals(elem) ) {
+				String cssClass = attributes.getValue("class");
+				if(cssClass != null && cssClass.contains("olatFlashMovieViewer")) {
+					count++;
+				}
+			}
+		}
+	}
 }

src/main/java/org/olat/ims/qti21/ui/editor/FeedbacksEditorController.java

@@ -43,8 +43,6 @@ import org.olat.core.gui.components.link.Link;
 import org.olat.core.gui.control.Controller;
 import org.olat.core.gui.control.WindowControl;
 import org.olat.core.util.CodeHelper;
-import org.olat.core.util.StringHelper;
-import org.olat.core.util.filter.FilterFactory;
 import org.olat.core.util.vfs.VFSContainer;
 import org.olat.ims.qti21.model.xml.AssessmentItemBuilder;
 import org.olat.ims.qti21.model.xml.ModalFeedbackBuilder;
@@ -52,6 +50,7 @@ import org.olat.ims.qti21.model.xml.ModalFeedbackBuilder.ModalFeedbackType;
 import org.olat.ims.qti21.model.xml.ModalFeedbackCondition;
 import org.olat.ims.qti21.model.xml.ResponseIdentifierForFeedback;
 import org.olat.ims.qti21.model.xml.ResponseIdentifierForFeedback.Answer;
+import org.olat.ims.qti21.model.xml.TestFeedbackBuilder;
 import org.olat.ims.qti21.ui.ResourcesMapper;
 import org.olat.ims.qti21.ui.components.FlowFormItem;
 import org.olat.ims.qti21.ui.editor.events.AssessmentItemEvent;
@@ -287,13 +286,13 @@ public class FeedbacksEditorController extends FormBasicController implements Sy
 	
 	@Override
 	protected boolean validateFormLogic(UserRequest ureq) {
-		boolean allOk = true;
+		boolean allOk = super.validateFormLogic(ureq);
 		
 		for(RuledFeedbackForm additionalForm:additionalForms) {
 			allOk &= additionalForm.validateFormLogic();
 		}
 		
-		return allOk & super.validateFormLogic(ureq);
+		return allOk;
 	}
 
 	@Override
@@ -353,8 +352,7 @@ public class FeedbacksEditorController extends FormBasicController implements Sy
 		}
 
 		public boolean isEmpty() {
-			String val = textEl.getValue();
-			return !StringHelper.containsNonWhitespace(FilterFactory.getHtmlTagsFilter().filter(val));
+			return TestFeedbackBuilder.isEmpty(textEl.getValue());
 		}
 		
 		public boolean isVisible() {
@@ -368,7 +366,7 @@ public class FeedbacksEditorController extends FormBasicController implements Sy
 		public void commit() {
 			String title = titleEl.getValue();
 			String text = textEl.getRawValue();
-			if(StringHelper.containsNonWhitespace(FilterFactory.getHtmlTagsFilter().filter(text))) {
+			if(!TestFeedbackBuilder.isEmpty(text) ) {
 				feedbackBuilder = itemBuilder.getFeedbackBuilder(feedbackType);
 				if(feedbackBuilder == null) {
 					feedbackBuilder = itemBuilder.createFeedbackBuilder(feedbackType);
@@ -496,7 +494,7 @@ public class FeedbacksEditorController extends FormBasicController implements Sy
 				feedbackConditions.add(condition.commit());
 			}
 			
-			if(StringHelper.containsNonWhitespace(FilterFactory.getHtmlTagsFilter().filter(text)) && feedbackConditions.size() > 0) {
+			if(!TestFeedbackBuilder.isEmpty(text) && !feedbackConditions.isEmpty()) {
 				if(feedbackBuilder == null) {
 					feedbackBuilder = itemBuilder.createFeedbackBuilder(feedbackType);
 				}
@@ -735,13 +733,11 @@ public class FeedbacksEditorController extends FormBasicController implements Sy
 				textValueEl.setVisible(!responseVar);
 				dropDownValueEl.setVisible(responseVar);
 				
-				String[] answerKeys = new String[] {};
-				String[] answerValues = new String[] {};
 				if(itemBuilder instanceof ResponseIdentifierForFeedback) {
 					ResponseIdentifierForFeedback responseFeedback = (ResponseIdentifierForFeedback)itemBuilder;
 					List<Answer> answers = responseFeedback.getAnswers();
-					answerKeys = new String[answers.size()];
-					answerValues = new String[answers.size()];
+					String[] answerKeys = new String[answers.size()];
+					String[] answerValues = new String[answers.size()];
 					
 					for(int i=0; i<answers.size(); i++) {
 						Answer answer = answers.get(i);