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;

	}

}