1 /*
2 * Copyright (C) 2007 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package com.google.common.io;
18
19 import com.google.common.annotations.Beta;
20
21 import java.io.FilterOutputStream;
22 import java.io.IOException;
23 import java.io.OutputStream;
24
25 import javax.annotation.Nullable;
26
27 /**
28 * An OutputStream that counts the number of bytes written.
29 *
30 * @author Chris Nokleberg
31 * @since 1.0
32 */
33 @Beta
34 public final class CountingOutputStream extends FilterOutputStream {
35
36 private long count;
37
38 /**
39 * Wraps another output stream, counting the number of bytes written.
40 *
41 * @param out the output stream to be wrapped
42 */
43 public CountingOutputStream(@Nullable OutputStream out) {
44 super(out);
45 }
46
47 /** Returns the number of bytes written. */
48 public long getCount() {
49 return count;
50 }
51
52 @Override public void write(byte[] b, int off, int len) throws IOException {
53 out.write(b, off, len);
54 count += len;
55 }
56
57 @Override public void write(int b) throws IOException {
58 out.write(b);
59 count++;
60 }
61
62 // Overriding close() because FilterOutputStream's close() method pre-JDK8 has bad behavior:
63 // it silently ignores any exception thrown by flush(). Instead, just close the delegate stream.
64 // It should flush itself if necessary.
65 @Override public void close() throws IOException {
66 out.close();
67 }
68 }