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history/016b_twoinput_unfinish/src/main/java/com/gitee/drinkjava2/frog/objects/EnvObject.java

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+/* Copyright 2018-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
+ * OF ANY KIND, either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ */
+package com.gitee.drinkjava2.frog.objects;
+
+import java.awt.Graphics;
+
+/**
+ * EnvObject means some virtual object in Env
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+public interface EnvObject {//EnvObject接口代表虚拟环境中的一种物体，每定义一个物体，要在Env的things变量中添加它
+
+    public void build(Graphics g);// 在Env中创建本身物体，只在每屏测试前调用一次
+
+    public void destory(Graphics g);// 从Env中清除本身物体，只在每屏测试完成后调用一次
+
+    public void active(int screen, int step, Graphics g);// 每个步长（即时间最小单位)都会调用一次这个方法, 前两个参数分别是当前屏数和当前步长数
+
+    public static class DefaultEnvObject implements EnvObject {//EnvObject接口的缺省实现
+
+        public void build(Graphics g) {
+        }
+
+        public void destory(Graphics g) {
+        }
+
+        public void active(int screen, int step, Graphics g) {
+        }
+    }
+}