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 * https://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.FilterWriter;
20 import java.io.IOException;
21 import java.io.Writer;
22
23 import org.apache.commons.io.IOUtils;
24
25 /**
26 * Writer which breaks larger output blocks into chunks.
27 * Native code may need to copy the input array; if the write buffer
28 * is very large this can cause OOME.
29 *
30 * @since 2.5
31 */
32 public class ChunkedWriter extends FilterWriter {
33
34 /**
35 * The default chunk size to use: {@value} bytes.
36 */
37 private static final int DEFAULT_CHUNK_SIZE = IOUtils.DEFAULT_BUFFER_SIZE;
38
39 /**
40 * The maximum chunk size to us when writing data arrays
41 */
42 private final int chunkSize;
43
44 /**
45 * Constructs a new writer that uses a chunk size of {@link #DEFAULT_CHUNK_SIZE}
46 * @param writer the writer to wrap
47 */
48 public ChunkedWriter(final Writer writer) {
49 this(writer, DEFAULT_CHUNK_SIZE);
50 }
51
52 /**
53 * Constructs a new writer that uses the specified chunk size.
54 *
55 * @param writer the writer to wrap
56 * @param chunkSize the chunk size to use; must be a positive number.
57 * @throws IllegalArgumentException if the chunk size is <= 0
58 */
59 public ChunkedWriter(final Writer writer, final int chunkSize) {
60 super(writer);
61 if (chunkSize <= 0) {
62 throw new IllegalArgumentException();
63 }
64 this.chunkSize = chunkSize;
65 }
66
67 /**
68 * Writes the data buffer in chunks to the underlying writer.
69 *
70 * @param data The data
71 * @param srcOffset the offset
72 * @param length the number of bytes to write
73 * @throws IOException upon error
74 */
75 @Override
76 public void write(final char[] data, final int srcOffset, final int length) throws IOException {
77 int bytes = length;
78 int dstOffset = srcOffset;
79 while (bytes > 0) {
80 final int chunk = Math.min(bytes, chunkSize);
81 out.write(data, dstOffset, chunk);
82 bytes -= chunk;
83 dstOffset += chunk;
84 }
85 }
86
87 }