org.apache.commons.io.output.CountingOutputStream Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.io.output;
import java.io.OutputStream;
/**
* A decorating output stream that counts the number of bytes that have passed
* through the stream so far.
*
* A typical use case would be during debugging, to ensure that data is being
* written as expected.
*
*/
public class CountingOutputStream extends ProxyOutputStream {
/** The count of bytes that have passed. */
private long count = 0;
/**
* Constructs a new CountingOutputStream.
*
* @param out the OutputStream to write to
*/
public CountingOutputStream( final OutputStream out ) {
super(out);
}
//-----------------------------------------------------------------------
/**
* Updates the count with the number of bytes that are being written.
*
* @param n number of bytes to be written to the stream
* @since 2.0
*/
@Override
protected synchronized void beforeWrite(final int n) {
count += n;
}
//-----------------------------------------------------------------------
/**
* The number of bytes that have passed through this stream.
*
* NOTE: From v1.3 this method throws an ArithmeticException if the
* count is greater than can be expressed by an int.
* See {@link #getByteCount()} for a method using a long.
*
* @return the number of bytes accumulated
* @throws ArithmeticException if the byte count is too large
*/
public int getCount() {
final long result = getByteCount();
if (result > Integer.MAX_VALUE) {
throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
}
return (int) result;
}
/**
* Set the byte count back to 0.
*
* NOTE: From v1.3 this method throws an ArithmeticException if the
* count is greater than can be expressed by an int.
* See {@link #resetByteCount()} for a method using a long.
*
* @return the count previous to resetting
* @throws ArithmeticException if the byte count is too large
*/
public int resetCount() {
final long result = resetByteCount();
if (result > Integer.MAX_VALUE) {
throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
}
return (int) result;
}
/**
* The number of bytes that have passed through this stream.
*
* NOTE: This method is an alternative for getCount().
* It was added because that method returns an integer which will
* result in incorrect count for files over 2GB.
*
* @return the number of bytes accumulated
* @since 1.3
*/
public synchronized long getByteCount() {
return this.count;
}
/**
* Set the byte count back to 0.
*
* NOTE: This method is an alternative for resetCount().
* It was added because that method returns an integer which will
* result in incorrect count for files over 2GB.
*
* @return the count previous to resetting
* @since 1.3
*/
public synchronized long resetByteCount() {
final long tmp = this.count;
this.count = 0;
return tmp;
}
}