clientmanager.java

Java 议程管理系统。使用GoF设计模式进行系统设计

/**
 * 
 */
package agenda.model;

import java.util.*;

/**
 * client manager implementation for manager design pattern
 * 
 * @author Cyberpet
 * 
 */
public class ClientManager {

	private ArrayList<Client> clientList = new ArrayList<Client>();

	/*
	 * add a user
	 */
	public boolean addUser(Client client) {
		if (this.getClientByName(client.getName()) == null)
			return this.clientList.add(client);
		else
			return false;
	}

	/*
	 * judge a user has been contained in list yet
	 */
	public boolean isContained(String name) {
		return this.getClientByName(name) != null;
	}

	public boolean addUser(String name, String psw) {
		if (this.getClientByName(name) == null) {
			this.clientList.add(new Client(name, psw));
			return true;
		} else
			return false;
	}

	/*
	 * remove user
	 */
	public boolean removeUser(String name) {
		return this.clientList.remove(this.getClientByName(name));
	}

	/*
	 * retrieve client instance by user name
	 */
	public Client getClientByName(String name) {
		for (Client clt : this.clientList)
			if (clt.getName().compareTo(name) == 0)
				return clt;
		return null;
	}

	// if object is not contained in list, return -1
	public int getIndexByName(String name) {
		return this.clientList.indexOf(this.getClientByName(name));
	}

	/*
	 * register a user
	 */
	public boolean regUser(String name, String psw) {
		Client clt = this.getClientByName(name);
		return clt != null && clt.getPsw().compareTo(psw) == 0;
	}

	/**
	 * static class for Singleton design pattern, instance of ClientManager will
	 * be created when the first time you make a call to
	 * ClientManager.getInstance
	 * 
	 * @author Cyberpet
	 * @see MeetingManager#getInstance()
	 */
	static class ClientManagerSingletonHolder {
		static ClientManager instance = new ClientManager();
	}

	/**
	 * get the only instance of ClientManager
	 * 
	 * @return ClientManager
	 * @see ClientManager
	 */
	public static ClientManager getInstance() {
		return ClientManagerSingletonHolder.instance;
	}

	public String toString() {
		String res = new String();
		for (Client clt : this.clientList)
			res += clt.toString() + "\n";
		return new String(res);
	}

	/**
	 * @param args
	 * @return void
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Client clt1 = new Client("", "");
		Client clt2 = new Client("abc", "0");
		Client clt3 = new Client("123", "wert");
		ClientManager.getInstance().addUser(clt1);
		ClientManager.getInstance().addUser(clt2);
		ClientManager.getInstance().addUser(clt3);
		System.out.println(ClientManager.getInstance().toString());
		ClientManager.getInstance().removeUser("123");
		System.out.println(ClientManager.getInstance().toString());

		if (ClientManager.getInstance().regUser("abc", "0"))
			// ClientManager.getInstance().regUser("abc", "")
			System.out.println("registed!");
		else
			System.out.println("not registed!");

	}

}