装饰者模式实际应用

Java IO类采用了装饰者模式：
利用装饰者模式会产生很多的小类。
InputStream
子类:FileInputStream StringBufferInputStream ByteArrayInputStream FilterInputStream

FilterInputStream子类:PushbackInputStream BufferedInputStream DataInputStream LineNumberInputStream

下面利用装饰者模式，写一个IO类自己的装饰者:
将输入流的大写字符全部转换小写字符。
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

public class LowerCaseInputStream extends FilterInputStream{

protected LowerCaseInputStream(InputStream in) {    super(in);}public int read() throws IOException{    int c = super.read();    return (c==-1 ?c :Character.toLowerCase((char)c));}public int read(byte[] b,int offset,int len) throws IOException{    int result = super.read(b, offset, len);    for(int i = offset; i < offset +result;i++){        b[i] = (byte)Character.toLowerCase((char)b[i]);    }    return result;}

}

测试运行类:
package com.gac.zsz;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

public class InputTest {
public static void main(String[] args){
int c;
try {
InputStream in = new LowerCaseInputStream(new BufferedInputStream(
new FileInputStream(“test.txt”)));
while((c = in.read())>=0){
System.out.println((char)c);
}
in.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}