@@ -0,0 +1,1060 @@
+/*%0A * JaamSim Discrete Event Simulation%0A * Copyright (C) 2017 JaamSim Software Inc.%0A *%0A * Licensed under the Apache License, Version 2.0 (the %22License%22);%0A * you may not use this file except in compliance with the License.%0A * You may obtain a copy of the License at%0A *%0A *     http://www.apache.org/licenses/LICENSE-2.0%0A *%0A * Unless required by applicable law or agreed to in writing, software%0A * distributed under the License is distributed on an %22AS IS%22 BASIS,%0A * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.%0A * See the License for the specific language governing permissions and%0A * limitations under the License.%0A */%0Apackage com.jaamsim.Commands;%0A%0Apublic interface Command %7B%0A%0A%09/**%0A%09 * Performs the change to the model.%0A%09 */%0A%09public void execute();%0A%0A%09/**%0A%09 * Reverses the change to the model.%0A%09 */%0A%09public void undo();%0A%0A%09/**%0A%09 * Attempts to merge this command with the specified command.%0A%09 * @param cmd - command to merge%0A%09 * @return merged command or null if commands are incompatible%0A%09 */%0A%09public Command tryMerge(Command cmd);%0A%7D%0A

add the Command interface for performing undo and redo