格式化的输入域

格式化的输入域
 //格式化的输入域
import java.awt.*;
import java.awt.event.*;
import java.lang.reflect.*;
import java.net.*;
import java.text.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;

public class FormatTest 
{
	public static void main(String[] args) 
	{
     FormatTestFrame frame=new FormatTestFrame();
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     frame.setVisible(true);
	}
}
//A frame with a collection of formatted text fields and a button that displays the field values.
class FormatTestFrame extends JFrame
{
	public FormatTestFrame()
	{
		setTitle("FormatTest");
		setSize(WIDTH,HEIGHT);
		
		JPanel buttonPanel=new JPanel();
		okButton=new JButton("OK");
		buttonPanel.add(okButton);
		add(buttonPanel,BorderLayout.SOUTH);
		
		mainPanel=new JPanel();
		mainPanel.setLayout(new GridLayout(0,3));
		add(mainPanel,BorderLayout.CENTER);
		
		JFormattedTextField intField=new JFormattedTextField(NumberFormat.getIntegerInstance());
		intField.setValue(new Integer(100));
		addRow("Number:",intField);
		
		JFormattedTextField intField2=new JFormattedTextField(NumberFormat.getIntegerInstance());
		intField.setValue(new Integer(100));
		intField2.setFocusLostBehavior(JFormattedTextField.COMMIT);
		addRow("Number(Commit behavior):",intField2);
		
		//这是安装格式器产生想要的过滤器的程序。
		JFormattedTextField intField3=new JFormattedTextField(new InternationalFormatter(NumberFormat.getIntegerInstance())
		{
			protected DocumentFilter getDocumentFilter()
			{
				return filter;
			}
			private DocumentFilter filter=new IntFilter();
		});
		
		intField3.setValue(new Integer(100));
		addRow("Filtered Number",intField3);
		
		JFormattedTextField intField4=new JFormattedTextField(NumberFormat.getIntegerInstance());
		intField4.setValue(new Integer(100));
		intField4.setInputVerifier(new FormattedTextFieldVerifier());
		addRow("Verified Number:",intField4);
		
		JFormattedTextField currencyField=new JFormattedTextField(NumberFormat.getIntegerInstance());
		currencyField.setValue(new Double(10));
		addRow("Currency:",currencyField);
		
		JFormattedTextField dateField=new JFormattedTextField(DateFormat.getDateInstance());
		dateField.setValue(new Date());
		addRow("Date(default):",dateField);
		DateFormat format=DateFormat.getDateInstance(DateFormat.SHORT);
		format.setLenient(false);
		JFormattedTextField dateField2=new JFormattedTextField(format);
		dateField2.setValue(new Date());
	    addRow("Date(short,not lenient):",dateField2);
	    
	    try
	    {
	    	DefaultFormatter formatter=new DefaultFormatter();
	    	formatter.setOverwriteMode(false);
	    	JFormattedTextField urlField=new JFormattedTextField(formatter);
	    	urlField.setValue(new URL("http://java.sun.com"));
	    	addRow("URL:",urlField);
	    }
		catch(MalformedURLException e)
		{
			e.printStackTrace();
		}
	
	try
	{
		MaskFormatter formatter=new MaskFormatter("###-##-####");
		//注意，字符串是被掩码格式器格式化的，它和掩码具有完全相同的长度。如果用户在编辑过程中删除字符，那么它们将被占位符（holer character)替代。
		//默认的占位字符是空格，可以使用setPlaceholderCharacter方法改变它。
		formatter.setPlaceholderCharacter('0');
		JFormattedTextField ssnField=new JFormattedTextField(formatter);
		ssnField.setValue("078-05-1120");
		addRow("SSN Mask:",ssnField);
	}
	catch(ParseException e)
	{
		e.printStackTrace();
	}
	
	JFormattedTextField ipField=new JFormattedTextField(new IPAddressFormatter());
	ipField.setValue(new byte[]{(byte)130,65,86,66});
	addRow("IP Address:",ipField);
}

//adds a row to the main panel.

public void  addRow(String labelText,final JFormattedTextField field)
{
	mainPanel.add(new JLabel(labelText));
	mainPanel.add(field);
	final JLabel valueLabel=new JLabel();
	mainPanel.add(valueLabel);
	okButton.addActionListener(new ActionListener()
	{
		public void actionPerformed(ActionEvent event)
		{
			Object value=field.getValue();
			if(value.getClass().isArray())
			{
				StringBuilder builder=new StringBuilder();
				builder.append('{');
				for(int i=0;i<Array.getLength(value);i++)
				{
					if(i>0)builder.append(',');
					builder.append(Array.get(value,i).toString());
				}
				builder.append('}');
				valueLabel.setText(builder.toString());
			}
			else
				valueLabel.setText(value.toString());
		}
	});
}
public static final int WIDTH=500;
public static final int HEIGHT=250;

private JButton okButton;
private JPanel mainPanel;
}

//A filter that restricts input to digits and a '-' sign.
//过滤器的方法：可以阻止用户输入非数字。
//此段程序中的文本域只能插入数字或者是负号”-“。
class IntFilter extends DocumentFilter
{
	public void insertString(FilterBypass fb,int offset,String string,AttributeSet attr)throws BadLocationException
	{
		StringBuilder builder=new StringBuilder(string);
		for(int i=builder.length()-1;i>=0;i--)
		{
			int cp=builder.codePointAt(i);
			if(!Character.isDigit(cp)&&cp!='-')
			{
				builder.deleteCharAt(i);
				if(Character.isSupplementaryCodePoint(cp))
				{
					i--;
					builder.deleteCharAt(i);
				}
			}
		}
		super.insertString(fb,offset,builder.toString(),attr);
	}
	public void replace(FilterBypass fb,int offset,int length,String string,AttributeSet attr)throws BadLocationException
	{
		if(string!=null)
		{
			StringBuilder builder=new StringBuilder(string);
			for(int i=builder.length()-1;i>=0;i--)
			{
				int cp=builder.codePointAt(i);
				if(!Character.isDigit(cp)&&cp!='-')
				{
					builder.deleteCharAt(i);
					if(Character.isSupplementaryCodePoint(cp))
					{
						i--;
						builder.deleteCharAt(i);
					}
				}
			}
			string=builder.toString();
		}
		super.replace(fb,offset,length,string,attr);
	}
}

//A verifier that checks whether the content of a formatted text field is valid.
//检验器 ：它用来警告用户以避免无效的输入。可以给任何JComponent附加检验器（verifier)。如果组件失去焦点，就询问检验器。
//如果检验器报告组件中的内容是无效的，组件马上就会重获焦点。因此，用户在提供其他输入之前，必须先修正无效的内容。 
//检验器必须扩展抽象类InputVerifier,并且定义verify方法。
class FormattedTextFieldVerifier extends InputVerifier
{
	public boolean verify(JComponent component)
	{
		JFormattedTextField field=(JFormattedTextField)component;
		return field.isEditValid();
	}
}

//A formatter for 4-byte IP address of the form a,b,c,d
class IPAddressFormatter extends DefaultFormatter
{
	public String valueToString(Object value)throws ParseException
	{
		if(!(value instanceof byte[]))
			throw new ParseException("Not a byte[]",0);
		byte[] a=(byte[]) value;
		if(a.length!=4)
			throw new ParseException("Length!=4",0);
		StringBuilder builder=new StringBuilder();
		for(int i=0;i<4;i++)
		{
			int b=a[i];
			if(b<0)b+=256;
			builder.append(String.valueOf(b));
			if(i<3)builder.append('.');
		}
		return builder.toString();
	}
	public Object stringToValue(String text)throws ParseException
	{
		StringTokenizer tokenizer=new StringTokenizer(text,".");
		byte[] a=new byte[4];
		for(int i=0;i<4;i++)
		{
			int b=0;
			if(!tokenizer.hasMoreTokens())
				throw new ParseException("Too few bytes",0);
			try
			{
				b=Integer.parseInt(tokenizer.nextToken());
			}
			catch(NumberFormatException e){
				throw new ParseException("Not an integer",0);
			}
			if(b<0 || b>=256)
				throw new ParseException("Byte out of range",0);
			a[i]=(byte)b;
		}
		if(tokenizer.hasMoreTokens())
			throw new ParseException("Too many bytes",0);
		return a;
	}
}