Add base files

src/main/java/com/university/chat/Common/ChatMessage.java

@@ -0,0 +1,25 @@
+package com.university.chat.Common;
+
+import java.io.Serializable;
+
+public class ChatMessage implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private MessageType type;
+    private String sender;
+    private String receiver;
+    private String content;
+
+    public ChatMessage(MessageType type, String sender, String receiver, String content) {
+        this.type = type;
+        this.sender = sender;
+        this.receiver = receiver;
+        this.content = content;
+    }
+
+    public MessageType getType() { return type; }
+    public String getSender() { return sender; }
+    public String getReceiver() { return receiver; }
+    public String getContent() { return content; }
+}

src/main/java/com/university/chat/Common/FileMessage.java

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+package com.university.chat.Common;
+
+import java.io.Serializable;
+
+public class FileMessage implements Serializable {
+
+    private static final long SerialVersionUID = 1L;
+
+    private String sender;
+    private String receiver;
+    private String filename;
+    private byte[] data;
+
+    public FileMessage(String sender, String receiver, String filename, byte[] data) {
+        this.sender = sender;
+        this.receiver = receiver;
+        this.filename = filename;
+        this.data = data;
+    }
+
+    public String getSender() {
+        return sender;
+    }
+
+    public String getReceiver() {
+        return receiver;
+    }
+
+    public String getFilename() {
+        return filename;
+    }
+
+    public byte[] getData() {
+        return data;
+    }
+}

src/main/java/com/university/chat/Common/MessageType.java

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+package com.university.chat.Common;
+
+import java.io.Serializable;
+
+public enum MessageType implements Serializable {
+    LOGIN,
+    LOGIN_SUCCESS,
+    LOGIN_FAILED,
+    PUBLIC_MESSAGE,
+    PRIVATE_MESSAGE,
+    USER_LIST,
+    FILE_TRANSFER
+}