/*
* 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 static java.lang.System.out;
import java.io.BufferedReader;
import java.io.CharArrayReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.Arrays;
public class GrowBufferedReader {
private static final int srcBufSize = 10 * 1024;
private static char[] src = new char[srcBufSize];
static {
src[srcBufSize - 1] = 'x';
}
private static CharArrayReader car = new CharArrayReader(src);
public static void main(String... args) {
try {
BufferedReader br = new BufferedReader(car);
Class c = br.getClass();
Field f = c.getDeclaredField("cb");
// cb is a private field
f.setAccessible(true);
char[] cbVal = char[].class.cast(f.get(br));
char[] newVal = Arrays.copyOf(cbVal, cbVal.length * 2);
if (args.length > 0 && args[0].equals("grow"))
f.set(br, newVal);
for (int i = 0; i < srcBufSize; i++)
br.read();
// see if the new backing array is being used
if (newVal[srcBufSize - 1] == src[srcBufSize - 1])
out.format("Using new backing array, size=%d%n", newVal.length);
else
out.format("Using original backing array, size=%d%n", cbVal.length);
// production code should handle these exceptions more gracefully
} catch (FileNotFoundException x) {
x.printStackTrace();
} catch (NoSuchFieldException x) {
x.printStackTrace();
} catch (IllegalAccessException x) {
x.printStackTrace();
} catch (IOException x) {
x.printStackTrace();
}
}
}