Added a no operation session manager

Author: Marcel Overdijk

rivescript-core/src/main/java/com/rivescript/session/ConcurrentHashMapSessionManager.java

@@ -32,7 +32,7 @@
 import static com.rivescript.session.ThawAction.THAW;
 
 /**
- * Implements the default in-memory session store for RiveScript, based on a {@link ConcurrentHashMap}.
+ * Implements the default in-memory {@link SessionManager} for RiveScript, based on a {@link ConcurrentHashMap}.
  *
  * @author Noah Petherbridge
  * @author Marcel Overdijk
@@ -184,7 +184,7 @@ private UserData cloneUser(UserData data) {
 	 * <p>
 	 * This mostly just means the topic is set to "random".
 	 *
-	 * @return
+	 * @return the user data
 	 */
 	private UserData defaultSession() {
 		UserData userData = new UserData();

rivescript-core/src/main/java/com/rivescript/session/NoOpSessionManager.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2016 the original author or authors.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.rivescript.session;
+
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * A no operation {@link SessionManager} suitable for disabling session storage.
+ *
+ * @author Noah Petherbridge
+ * @author Marcel Overdijk
+ */
+public class NoOpSessionManager implements SessionManager {
+
+	@Override
+	public UserData init(String username) {
+		return noOpSession();
+	}
+
+	@Override
+	public void set(String username, String name, String value) {
+	}
+
+	@Override
+	public void set(String username, Map<String, String> vars) {
+	}
+
+	@Override
+	public void addHistory(String username, String input, String reply) {
+	}
+
+	@Override
+	public void setLastMatch(String username, String trigger) {
+	}
+
+	@Override
+	public String get(String username, String name) {
+		return null;
+	}
+
+	@Override
+	public UserData get(String username) {
+		return null;
+	}
+
+	@Override
+	public Map<String, UserData> getAll() {
+		return Collections.emptyMap();
+	}
+
+	@Override
+	public String getLastMatch(String username) {
+		return null;
+	}
+
+	@Override
+	public History getHistory(String username) {
+		return new History();
+	}
+
+	@Override
+	public void clear(String username) {
+	}
+
+	@Override
+	public void clearAll() {
+	}
+
+	@Override
+	public void freeze(String username) {
+	}
+
+	@Override
+	public void thaw(String username, ThawAction action) {
+	}
+
+	private UserData noOpSession() {
+		UserData userData = new UserData();
+		userData.setLastMatch("");
+		return userData;
+	}
+}