Add class to evict caches based on events

src/main/java/de/thm/arsnova/dao/CacheBustListener.java

+/*
+ * This file is part of ARSnova Backend.
+ * Copyright (C) 2012-2015 The ARSnova Team
+ *
+ * ARSnova Backend is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ARSnova Backend 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.thm.arsnova.dao;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationListener;
+import org.springframework.stereotype.Component;
+
+import de.thm.arsnova.events.NovaEvent;
+import de.thm.arsnova.events.NovaEventVisitor;
+
+@Component
+public class CacheBustListener implements ApplicationListener<NovaEvent> {
+
+	@Autowired
+	private ICacheBuster cacheBuster;
+
+	@Override
+	public void onApplicationEvent(NovaEvent event) {
+		event.accept((NovaEventVisitor) cacheBuster);
+	}
+
+}

src/main/java/de/thm/arsnova/dao/CacheBuster.java

+/*
+ * This file is part of ARSnova Backend.
+ * Copyright (C) 2012-2015 The ARSnova Team
+ *
+ * ARSnova Backend is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ARSnova Backend 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.thm.arsnova.dao;
+
+import org.springframework.cache.annotation.CacheEvict;
+import org.springframework.stereotype.Component;
+
+import de.thm.arsnova.events.DeleteAllLectureAnswersEvent;
+import de.thm.arsnova.events.DeleteAllPreparationAnswersEvent;
+import de.thm.arsnova.events.DeleteAllQuestionsAnswersEvent;
+import de.thm.arsnova.events.DeleteAnswerEvent;
+import de.thm.arsnova.events.DeleteFeedbackForSessionsEvent;
+import de.thm.arsnova.events.DeleteInterposedQuestionEvent;
+import de.thm.arsnova.events.DeleteQuestionEvent;
+import de.thm.arsnova.events.NewAnswerEvent;
+import de.thm.arsnova.events.NewFeedbackEvent;
+import de.thm.arsnova.events.NewInterposedQuestionEvent;
+import de.thm.arsnova.events.NewQuestionEvent;
+import de.thm.arsnova.events.NovaEventVisitor;
+import de.thm.arsnova.events.StatusSessionEvent;
+
+/**
+ * This class is used to evict caches based on events. The events carry all necessary information to clear the
+ * caches, e.g, for a specific session.
+ */
+@Component
+public class CacheBuster implements ICacheBuster, NovaEventVisitor {
+
+	@Override
+	public void visit(NewInterposedQuestionEvent event) {}
+
+	@Override
+	public void visit(DeleteInterposedQuestionEvent event) {}
+
+	@Override
+	public void visit(NewQuestionEvent event) {}
+
+	@CacheEvict(value = "answers", key = "#event.Session")
+	@Override
+	public void visit(NewAnswerEvent event) {}
+
+	@Override
+	public void visit(DeleteAnswerEvent event) {}
+
+	@Override
+	public void visit(DeleteQuestionEvent event) {}
+
+	@Override
+	public void visit(DeleteAllQuestionsAnswersEvent event) {}
+
+	@Override
+	public void visit(DeleteAllPreparationAnswersEvent event) {}
+
+	@Override
+	public void visit(DeleteAllLectureAnswersEvent event) {}
+
+	@Override
+	public void visit(NewFeedbackEvent event) {}
+
+	@Override
+	public void visit(DeleteFeedbackForSessionsEvent event) {}
+
+	@Override
+	public void visit(StatusSessionEvent event) {}
+}

src/main/java/de/thm/arsnova/dao/ICacheBuster.java

+/*
+ * This file is part of ARSnova Backend.
+ * Copyright (C) 2012-2015 The ARSnova Team
+ *
+ * ARSnova Backend is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ARSnova Backend 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.thm.arsnova.dao;
+
+/**
+ * This interface is used as a tag to make Spring dependency injection happy...
+ */
+public interface ICacheBuster {}