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.OutputStream;
20
21 /**
22 * A decorating output stream that counts the number of bytes that have passed
23 * through the stream so far.
24 * <p>
25 * A typical use case would be during debugging, to ensure that data is being
26 * written as expected.
27 *
28 * @version $Id: CountingOutputStream.java 1415850 2012-11-30 20:51:39Z ggregory $
29 */
30 public class CountingOutputStream extends ProxyOutputStream {
31
32 /** The count of bytes that have passed. */
33 private long count = 0;
34
35 /**
36 * Constructs a new CountingOutputStream.
37 *
38 * @param out the OutputStream to write to
39 */
40 public CountingOutputStream( final OutputStream out ) {
41 super(out);
42 }
43
44 //-----------------------------------------------------------------------
45
46 /**
47 * Updates the count with the number of bytes that are being written.
48 *
49 * @param n number of bytes to be written to the stream
50 * @since 2.0
51 */
52 @Override
53 protected synchronized void beforeWrite(final int n) {
54 count += n;
55 }
56
57 //-----------------------------------------------------------------------
58 /**
59 * The number of bytes that have passed through this stream.
60 * <p>
61 * NOTE: From v1.3 this method throws an ArithmeticException if the
62 * count is greater than can be expressed by an <code>int</code>.
63 * See {@link #getByteCount()} for a method using a <code>long</code>.
64 *
65 * @return the number of bytes accumulated
66 * @throws ArithmeticException if the byte count is too large
67 */
68 public int getCount() {
69 final long result = getByteCount();
70 if (result > Integer.MAX_VALUE) {
71 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
72 }
73 return (int) result;
74 }
75
76 /**
77 * Set the byte count back to 0.
78 * <p>
79 * NOTE: From v1.3 this method throws an ArithmeticException if the
80 * count is greater than can be expressed by an <code>int</code>.
81 * See {@link #resetByteCount()} for a method using a <code>long</code>.
82 *
83 * @return the count previous to resetting
84 * @throws ArithmeticException if the byte count is too large
85 */
86 public int resetCount() {
87 final long result = resetByteCount();
88 if (result > Integer.MAX_VALUE) {
89 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
90 }
91 return (int) result;
92 }
93
94 /**
95 * The number of bytes that have passed through this stream.
96 * <p>
97 * NOTE: This method is an alternative for <code>getCount()</code>.
98 * It was added because that method returns an integer which will
99 * 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 final long tmp = this.count;
120 this.count = 0;
121 return tmp;
122 }
123
124 }