grepreader.java

Java与模式 源代码

package com.javapatterns.decorator.grepr;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FilterReader;
import java.io.IOException;

public class GrepReader extends FilterReader
{
    protected String substring;
    protected BufferedReader in;
    private int lineNumber;

    public GrepReader(FileReader in, String substring)
    {
        super(in);
        this.in = new BufferedReader(in);
        this.substring = substring;
        lineNumber = 0;
    }

    public final String readLine() throws IOException
    {
        String line = null;
        do
        {
            line = in.readLine(); lineNumber++;
        }
        while ((line != null) && line.indexOf(substring) == -1);
        return line;
    }

    public int lineNo() { return lineNumber; }
}