fixedsizefield.java

用于传感器网络的节点操作系统 TinyOS 结构设计非常有意思

package net.tinyos.tinydb;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;

/** FixedSizeField is a JTextField that is constrained to be a fixed
    number of characters wide 
*/
public class FixedSizeField extends JTextField {
    int len;
    
    public FixedSizeField(int cols) {
	super(cols);
	len = cols;

    }
    protected Document createDefaultModel() {
	return new FixedSizeDocument();
    }
    class FixedSizeDocument extends PlainDocument
    {
	public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
	    if (getLength() + str.length() <= len) super.insertString(offs,str,a);
	}
    }	
}