countreader.java

java tutorial.sun公司官方出品。java入门书籍。最新版

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

import java.io.*;

public class CountReader extends FilterReader {

    private int count = 0;
    private char lookFor = 0;

    public CountReader(Reader in, char lookFor) {
        super(in);
        this.lookFor = lookFor;
    }
    public int read() throws IOException {
        int character = super.read();
        if ((char)character == lookFor) {
            count++;
        }
	return character;
    }
    public int read(char[] cbuf) throws IOException {
        int numChars = super.read(cbuf);
        int length = cbuf.length;
        for (int i = 0; i < length; i++) {
            if (cbuf[i] == lookFor) {
                count++;
            }
        }
	return numChars;
    }
    public int read(char[] cbuf, int off, int len) throws IOException {
        int numChars = super.read(cbuf, off, len);
        int length = cbuf.length;
        for (int i = 0; i < length; i++) {
            if (cbuf[i] == lookFor) {
                count++;
            }
        }
	return numChars;
    }
    public void reset() throws IOException {
        super.reset();
        count = 0;
    }
    public boolean markSupported() {
        return false;
    }
    public void mark(int readAheadLimit) throws IOException {
        throw new IOException("CountReader does not support the mark() operation.");
    }
    public int getCount() {
        return count;
    }
}