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.IOException;
020 import java.io.OutputStream;
021
022 /**
023 * A decorating output stream that counts the number of bytes that have passed
024 * through the stream so far.
025 * <p>
026 * A typical use case would be during debugging, to ensure that data is being
027 * written as expected.
028 *
029 * @version $Id: CountingOutputStream.java 471628 2006-11-06 04:06:45Z bayard $
030 */
031 public class CountingOutputStream extends ProxyOutputStream {
032
033 /** The count of bytes that have passed. */
034 private long count;
035
036 /**
037 * Constructs a new CountingOutputStream.
038 *
039 * @param out the OutputStream to write to
040 */
041 public CountingOutputStream( OutputStream out ) {
042 super(out);
043 }
044
045 //-----------------------------------------------------------------------
046 /**
047 * Writes the contents of the specified byte array to this output stream
048 * keeping count of the number of bytes written.
049 *
050 * @param b the bytes to write, not null
051 * @throws IOException if an I/O error occurs
052 * @see java.io.OutputStream#write(byte[])
053 */
054 public void write(byte[] b) throws IOException {
055 count += b.length;
056 super.write(b);
057 }
058
059 /**
060 * Writes a portion of the specified byte array to this output stream
061 * keeping count of the number of bytes written.
062 *
063 * @param b the bytes to write, not null
064 * @param off the start offset in the buffer
065 * @param len the maximum number of bytes to write
066 * @throws IOException if an I/O error occurs
067 * @see java.io.OutputStream#write(byte[], int, int)
068 */
069 public void write(byte[] b, int off, int len) throws IOException {
070 count += len;
071 super.write(b, off, len);
072 }
073
074 /**
075 * Writes a single byte to the output stream adding to the count of the
076 * number of bytes written.
077 *
078 * @param b the byte to write
079 * @throws IOException if an I/O error occurs
080 * @see java.io.OutputStream#write(int)
081 */
082 public void write(int b) throws IOException {
083 count++;
084 super.write(b);
085 }
086
087 //-----------------------------------------------------------------------
088 /**
089 * The number of bytes that have passed through this stream.
090 * <p>
091 * NOTE: From v1.3 this method throws an ArithmeticException if the
092 * count is greater than can be expressed by an <code>int</code>.
093 * See {@link #getByteCount()} for a method using a <code>long</code>.
094 *
095 * @return the number of bytes accumulated
096 * @throws ArithmeticException if the byte count is too large
097 */
098 public synchronized int getCount() {
099 long result = getByteCount();
100 if (result > Integer.MAX_VALUE) {
101 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
102 }
103 return (int) result;
104 }
105
106 /**
107 * Set the byte count back to 0.
108 * <p>
109 * NOTE: From v1.3 this method throws an ArithmeticException if the
110 * count is greater than can be expressed by an <code>int</code>.
111 * See {@link #resetByteCount()} for a method using a <code>long</code>.
112 *
113 * @return the count previous to resetting
114 * @throws ArithmeticException if the byte count is too large
115 */
116 public synchronized int resetCount() {
117 long result = resetByteCount();
118 if (result > Integer.MAX_VALUE) {
119 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
120 }
121 return (int) result;
122 }
123
124 /**
125 * The number of bytes that have passed through this stream.
126 * <p>
127 * NOTE: This method is an alternative for <code>getCount()</code>.
128 * It was added because that method returns an integer which will
129 * result in incorrect count for files over 2GB.
130 *
131 * @return the number of bytes accumulated
132 * @since Commons IO 1.3
133 */
134 public synchronized long getByteCount() {
135 return this.count;
136 }
137
138 /**
139 * Set the byte count back to 0.
140 * <p>
141 * NOTE: This method is an alternative for <code>resetCount()</code>.
142 * It was added because that method returns an integer which will
143 * result in incorrect count for files over 2GB.
144 *
145 * @return the count previous to resetting
146 * @since Commons IO 1.3
147 */
148 public synchronized long resetByteCount() {
149 long tmp = this.count;
150 this.count = 0;
151 return tmp;
152 }
153
154 }