1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io.output;
18
19 import java.io.IOException;
20 import java.io.OutputStream;
21
22 /**
23 * A decorating output stream that counts the number of bytes that have passed
24 * through the stream so far.
25 * <p>
26 * A typical use case would be during debugging, to ensure that data is being
27 * written as expected.
28 *
29 * @version $Id: CountingOutputStream.java 471628 2006-11-06 04:06:45Z bayard $
30 */
31 public class CountingOutputStream extends ProxyOutputStream {
32
33 /** The count of bytes that have passed. */
34 private long count;
35
36 /**
37 * Constructs a new CountingOutputStream.
38 *
39 * @param out the OutputStream to write to
40 */
41 public CountingOutputStream( OutputStream out ) {
42 super(out);
43 }
44
45 //-----------------------------------------------------------------------
46 /**
47 * Writes the contents of the specified byte array to this output stream
48 * keeping count of the number of bytes written.
49 *
50 * @param b the bytes to write, not null
51 * @throws IOException if an I/O error occurs
52 * @see java.io.OutputStream#write(byte[])
53 */
54 public void write(byte[] b) throws IOException {
55 count += b.length;
56 super.write(b);
57 }
58
59 /**
60 * Writes a portion of the specified byte array to this output stream
61 * keeping count of the number of bytes written.
62 *
63 * @param b the bytes to write, not null
64 * @param off the start offset in the buffer
65 * @param len the maximum number of bytes to write
66 * @throws IOException if an I/O error occurs
67 * @see java.io.OutputStream#write(byte[], int, int)
68 */
69 public void write(byte[] b, int off, int len) throws IOException {
70 count += len;
71 super.write(b, off, len);
72 }
73
74 /**
75 * Writes a single byte to the output stream adding to the count of the
76 * number of bytes written.
77 *
78 * @param b the byte to write
79 * @throws IOException if an I/O error occurs
80 * @see java.io.OutputStream#write(int)
81 */
82 public void write(int b) throws IOException {
83 count++;
84 super.write(b);
85 }
86
87 //-----------------------------------------------------------------------
88 /**
89 * The number of bytes that have passed through this stream.
90 * <p>
91 * NOTE: From v1.3 this method throws an ArithmeticException if the
92 * count is greater than can be expressed by an <code>int</code>.
93 * See {@link #getByteCount()} for a method using a <code>long</code>.
94 *
95 * @return the number of bytes accumulated
96 * @throws ArithmeticException if the byte count is too large
97 */
98 public synchronized int getCount() {
99 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 }