001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.io.output;
018
019 import java.io.OutputStream;
020
021 /**
022 * A decorating output stream that counts the number of bytes that have passed
023 * through the stream so far.
024 * <p>
025 * A typical use case would be during debugging, to ensure that data is being
026 * written as expected.
027 *
028 * @version $Id: CountingOutputStream.java 1304052 2012-03-22 20:55:29Z ggregory $
029 */
030 public class CountingOutputStream extends ProxyOutputStream {
031
032 /** The count of bytes that have passed. */
033 private long count = 0;
034
035 /**
036 * Constructs a new CountingOutputStream.
037 *
038 * @param out the OutputStream to write to
039 */
040 public CountingOutputStream( OutputStream out ) {
041 super(out);
042 }
043
044 //-----------------------------------------------------------------------
045
046 /**
047 * Updates the count with the number of bytes that are being written.
048 *
049 * @param n number of bytes to be written to the stream
050 * @since 2.0
051 */
052 @Override
053 protected synchronized void beforeWrite(int n) {
054 count += n;
055 }
056
057 //-----------------------------------------------------------------------
058 /**
059 * The number of bytes that have passed through this stream.
060 * <p>
061 * NOTE: From v1.3 this method throws an ArithmeticException if the
062 * count is greater than can be expressed by an <code>int</code>.
063 * See {@link #getByteCount()} for a method using a <code>long</code>.
064 *
065 * @return the number of bytes accumulated
066 * @throws ArithmeticException if the byte count is too large
067 */
068 public int getCount() {
069 long result = getByteCount();
070 if (result > Integer.MAX_VALUE) {
071 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
072 }
073 return (int) result;
074 }
075
076 /**
077 * Set the byte count back to 0.
078 * <p>
079 * NOTE: From v1.3 this method throws an ArithmeticException if the
080 * count is greater than can be expressed by an <code>int</code>.
081 * See {@link #resetByteCount()} for a method using a <code>long</code>.
082 *
083 * @return the count previous to resetting
084 * @throws ArithmeticException if the byte count is too large
085 */
086 public int resetCount() {
087 long result = resetByteCount();
088 if (result > Integer.MAX_VALUE) {
089 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
090 }
091 return (int) result;
092 }
093
094 /**
095 * The number of bytes that have passed through this stream.
096 * <p>
097 * NOTE: This method is an alternative for <code>getCount()</code>.
098 * It was added because that method returns an integer which will
099 * result in incorrect count for files over 2GB.
100 *
101 * @return the number of bytes accumulated
102 * @since 1.3
103 */
104 public synchronized long getByteCount() {
105 return this.count;
106 }
107
108 /**
109 * Set the byte count back to 0.
110 * <p>
111 * NOTE: This method is an alternative for <code>resetCount()</code>.
112 * It was added because that method returns an integer which will
113 * result in incorrect count for files over 2GB.
114 *
115 * @return the count previous to resetting
116 * @since 1.3
117 */
118 public synchronized long resetByteCount() {
119 long tmp = this.count;
120 this.count = 0;
121 return tmp;
122 }
123
124 }