Create and implement basic command

src/main/java/org/telegram/telegrambots/api/commands/Command.java

@@ -0,0 +1,75 @@
+package org.telegram.telegrambots.api.commands;
+
+import org.telegram.telegrambots.bots.AbsSender;
+
+/**
+ * Representation of a command, which can be executed
+ *
+ * @author tschulz
+ */
+public abstract class Command extends AbsSender {
+
+    public final static String COMMAND_INIT_CHARACTER = "/";
+    public final static String COMMAND_PARAMETER_SEPERATOR = " ";
+    private final static int COMMAND_MAX_LENGTH = 32;
+
+    private final String commandIdentifier;
+    private final String description;
+    private final String botToken;
+
+    /**
+     * construct a command
+     *
+     * @param commandIdentifier the unique identifier of this command (e.g. the command string to enter into chat)
+     * @param description       the description of this command
+     */
+    public Command(String commandIdentifier, String description, String botToken) {
+
+        if (commandIdentifier == null || commandIdentifier.isEmpty()) {
+            throw new IllegalArgumentException("commandIdentifier for command cannot be null or empty");
+        }
+
+        if (commandIdentifier.startsWith(COMMAND_INIT_CHARACTER)) {
+            commandIdentifier = commandIdentifier.substring(1);
+        }
+
+        if (commandIdentifier.length() + 1 > COMMAND_MAX_LENGTH) {
+            throw new IllegalArgumentException("commandIdentifier cannot be longer than " + COMMAND_MAX_LENGTH + " (including " + COMMAND_INIT_CHARACTER + ")");
+        }
+
+        this.commandIdentifier = commandIdentifier.toLowerCase();
+        this.description = description;
+        this.botToken = botToken;
+    }
+
+    /**
+     * get the identifier of this command
+     *
+     * @return the identifier
+     */
+    public final String getCommandIdentifier() {
+        return commandIdentifier;
+    }
+
+    /**
+     * get the description of this command
+     *
+     * @return the description as String
+     */
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public String getBotToken() {
+        return botToken;
+    }
+
+    /**
+     * execute the command
+     *
+     * @param arguments passed arguments
+     * @param chatId    id of the chat, to be able to send replies
+     */
+    abstract void execute(String[] arguments, long chatId);
+}