[Add][Change] Framework-API, Core 添加 Message 类型作为消息元素的基类, BotCode 继承 Message, AbstractBotCode 实现 BotCode 的相关方法细节;

[Add] Message, MessageChain 添加 Message 接口作为消息元素的基类, 添加 MessageChain 用于链接消息元素;
[Change] BotCode, AbstractBotCode BotCode 继承 Message 接口以作为消息的一部分, AbstractBotCode 实现部分方法细节;
[Add] BasicBotCode 适配调整, 添加新的构造方法;

ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/AbstractBotCode.java

@@ -116,4 +116,19 @@ public abstract class AbstractBotCode implements BotCode {
         return Collections.unmodifiableSet(functionProperties.keySet());
     }
 
+    @Override
+    public int length() {
+        return contentToString().length();
+    }
+
+    @Override
+    public char charAt(int index) {
+        return contentToString().charAt(index);
+    }
+
+    @Override
+    public CharSequence subSequence(int start, int end) {
+        return contentToString().subSequence(start, end);
+    }
+
 }

ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/BotCode.java

@@ -25,7 +25,8 @@ import java.util.Set;
  * 功能码接口.
  * @author LamGC
  */
-public interface BotCode {
+@SuppressWarnings("AlibabaAbstractMethodOrInterfaceMethodMustUseJavadoc")
+public interface BotCode extends Message {
 
     /**
      * 获取 BotCode 实现所属平台.

ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/Message.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.cgj.bot.framework.message;
+
+/**
+ * 消息接口.
+ * @author LamGC
+ */
+public interface Message extends CharSequence {
+
+    /**
+     * 消息内容到文本.
+     * @return 返回内容字符串.
+     */
+    String contentToString();
+
+}

ContentGrabbingJi-framework-api/src/main/java/net/lamgc/cgj/bot/framework/message/MessageChain.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.cgj.bot.framework.message;
+
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+/**
+ * 消息链.
+ * <p> 消息链代表了由一组元素组成的消息, 是一个消息内容的整体.
+ * @author LamGC
+ */
+public final class MessageChain implements Message {
+
+    private final List<Message> contents = new CopyOnWriteArrayList<>();
+
+    public MessageChain() {}
+
+    public MessageChain(CharSequence... contents) {
+        plus(contents);
+    }
+
+    public void plus(CharSequence... content) {
+        addMultiContents(content);
+    }
+
+    public void plus(Message... message) {
+        addMultiContents(message);
+    }
+
+    public void plus(BotCode... botCode) {
+        addMultiContents(botCode);
+    }
+
+    /**
+     * 添加多个内容.
+     * @param contents 内容数组.
+     * @see #addContent(Message) 底层实现.
+     */
+    private void addMultiContents(CharSequence[] contents) {
+        for (CharSequence content : contents) {
+            if (content instanceof Message) {
+                addContent((Message) content);
+            } else {
+                addContent(new CharSequenceMessage(content));
+            }
+        }
+    }
+
+    /**
+     * 添加消息内容.
+     * <p> plus 方法必须且只能通过该方法将内容段添加到 {@link #contents},
+     * 因为需要防止 MessageChain 自己添加自己.
+     * @param content 消息内容.
+     * @throws IllegalArgumentException 不允许 MessageChain 添加本身.
+     */
+    private void addContent(Message content) {
+        if (this.equals(content)) {
+            throw new IllegalArgumentException("Adding the MessageChain itself is not allowed");
+        }
+        contents.add(content);
+    }
+
+    @Override
+    public String contentToString() {
+        StringBuilder builder = new StringBuilder();
+        for (Message messageElement : contents) {
+            builder.append(messageElement.contentToString());
+        }
+        return builder.toString();
+    }
+
+    @Override
+    public int length() {
+        return contentToString().length();
+    }
+
+    @Override
+    public char charAt(int index) {
+        return contentToString().charAt(index);
+    }
+
+    @Override
+    public CharSequence subSequence(int start, int end) {
+        return contentToString().subSequence(start, end);
+    }
+
+}