/*
* This file is part of muCommander, http://www.mucommander.com
* Copyright (C) 2002-2016 Maxence Bernard
*
* muCommander is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* muCommander is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.mucommander.commons.io;
/**
* Contains a number of bytes which have been read/written from/to a {@link CounterInputStream}/{@link CounterOutputStream}.
*
* <p>Provided methods allow to read the the byte count, add a number bytes to it or reset it (make it zero).
*
* <p>This class is thread safe, ensuring that the counter is always in a consistent state.</p>
*
* @see com.mucommander.commons.io.CounterInputStream
* @see com.mucommander.commons.io.CounterOutputStream
* @author Maxence Bernard
*/
public class ByteCounter {
/** Byte count */
private long count;
/** Byte counter to add to the value returned by {@link #getByteCount()} */
private ByteCounter addedCounter;
/**
* Creates a new ByteCounter with an initial byte count equal to zero.
*/
public ByteCounter() {
}
/**
* Creates a new ByteCounter with an initial byte count equal to zero and using the given ByteCounter.
*
* <p>The value returned by {@link #getByteCount()} will be the sum of the internal byte count and the one from
* the specified ByteCounter, as returned by its {@link #getByteCount()} method. Resetting this ByteCounter's value
* will only affect the internal byte count and not the one from the specified ByteCounter.
*/
public ByteCounter(ByteCounter counter) {
this.addedCounter = counter;
}
/**
* Return the number of bytes which have been accounted for.
*/
public synchronized long getByteCount() {
if(addedCounter!=null)
return count + addedCounter.getByteCount();
return this.count;
}
/**
* Increases the byte counter by the provided number of bytes. If the specified number is negative,
* the byte counter will be left unchanged (won't be decreased).
*
* @param nbBytes number of bytes to add to the byte counter, will be ignored if negative
*/
public synchronized void add(long nbBytes) {
if(nbBytes>0)
this.count += nbBytes;
}
/**
* Increases the byte counter by the number of bytes contained in the specified counter (as returned by its
* {@link #getByteCount()} method) and resets its byte counter after (if specified).
*
* @param counter the Bytecounter to add to this one, and reset after (if specified).
* @param resetAfter if true, the specified counter will be reset after its byte count has been added to this ByteCounter
*/
public synchronized void add(ByteCounter counter, boolean resetAfter) {
// Hold a lock on the provided counter to make sure that it is not modified or accessed
// while this operation is carried out
synchronized(counter) {
add(counter.getByteCount());
if(resetAfter)
counter.reset();
}
}
/**
* Resets the byte counter (make it zero).
*/
public synchronized void reset() {
this.count = 0;
}
}