n2afilter.java

海天图书馆管理系统 使用Java开发

/*
 * @(#)N2AFilter.java	1.6 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/**
 * This FilterWriter class takes an existing Writer and uses
 * the 'back-tick U' escape notation to escape characters which are
 * encountered within the input character based stream which
 * are outside the 7-bit ASCII range. The native platforms linefeed 
 * character is emitted for each line of processed input 
 */

package net.sfte.htlibrary.util;

import java.io.*;

class N2AFilter extends FilterWriter {

	public N2AFilter(Writer out) {
		super(out);
	}

	public void write(char b) throws IOException {
		char[] buf = new char[1];
		buf[0] = (char) b;
		write(buf, 0, 1);
	}

	public void write(char[] buf, int off, int len) throws IOException {

		// System.err.println ("xx Out buffer length is " + buf.length );
		for (int i = 0; i < len; i++) {
			if ((buf[i] > '\u007f')) {
				// write \udddd
				out.write('\\');
				out.write('u');
				String hex = Integer.toHexString(buf[i]);
				StringBuffer hex4 = new StringBuffer(hex);
				hex4.reverse();
				int length = 4 - hex4.length();
				for (int j = 0; j < length; j++) {
					hex4.append('0');
				}
				for (int j = 0; j < 4; j++) {
					out.write(hex4.charAt(3 - j));
				}
			} else {
				out.write(buf[i]);
			}
		}
	}
}