【转】 State模式在客户端软件中的应用

public interface ClientStateChangeable {	
	/**
	 * To get all changeable components in the GUI object. 
	 * @return Collection contains Component objects. 
	 */
	Collection getChageableComponents();
	
	/**
	 * To save data to server.
	 */
	void saveChangeToServer();
}

public class AClientGUI extends JPanel implements ClientStateChangeable{
	//… 	
	private ClientState state = null;
public DesignStep1View(ClientState state){
//…			
this.state = state;
this.state.setComponents(this);
	}
	
	private void okButton_actionPerformed(ActionEvent e){
		state.action(this);	//save data
	}
	public Collection getChageableComponents() {
		Collection dataComponents = new ArrayList();		
		dataComponents.add(jComboBoxESEPattern);
		//…			
		return dataComponents;
	}
	public void saveChangeToServer() {
		//…	
	}
}

public class ClientNormalState implements ClientState {
	/**
	 * 正常状态下, 各个控件默认为可编辑的, 所以不用做任何更改
	 */
	public void setComponents(ClientStateChangeable gui) {}
	/** 
	 * 正常状态下, 需要将用户所作修改保存到服务端 
	 */
	public void action(ClientStateChangeable gui) {
		gui.saveChangeToServer();
	}
}

public class ClientReadOnlyState implements ClientState {
	/**
	 * 设置GUI的数据控件为Read-Only
	 */
public void setComponents(ClientStateChangeable gui) {
		Collection components = gui.getChageableComponents();
		Iterator iter = components.iterator();
		while(iter.hasNext()){
			JComponent jc = (JComponent)iter.next();
			jc.setEnabled(false);			
			String toolTip = jc.getToolTipText();
			String addedTip = "只读状态";
			if(toolTip == null)toolTip = addedTip;
			else toolTip += ". " + addedTip;
			jc.setToolTipText(toolTip); 
		}
	}
	/**
	 * GUI处于Read-Only状态, 无需将数据保存到server端	
	 */
	public void action(ClientStateChangeable gui) {}
}