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.File;
20 import java.io.IOException;
21 import java.io.InputStream;
22 import java.io.OutputStream;
23 import java.nio.file.Files;
24 import java.nio.file.Path;
25 import java.util.Objects;
26 import java.util.function.Supplier;
27
28 import org.apache.commons.io.build.AbstractStreamBuilder;
29 import org.apache.commons.io.file.PathUtils;
30
31 /**
32 * An output stream which will retain data in memory until a specified threshold is reached, and only then commit it to disk. If the stream is closed before the
33 * threshold is reached, the data will not be written to disk at all.
34 * <p>
35 * To build an instance, use {@link Builder}.
36 * </p>
37 * <p>
38 * The caller is responsible for deleting the output file ({@link #getFile()}, {@link #getPath()}) created by a DeferredFileOutputStream when the caller only
39 * configured a prefix.
40 * </p>
41 * <p>
42 * The caller is responsible for deleting the output file passed to a constructor or builder through {@link Builder#setOutputFile(File)} or
43 * {@link Builder#setOutputFile(Path)}.
44 * </p>
45 * <p>
46 * This class originated in FileUpload processing. In this use case, you do not know in advance the size of the file being uploaded. If the file is small you
47 * want to store it in memory (for speed), but if the file is large you want to store it to file (to avoid memory issues).
48 * </p>
49 *
50 * @see Builder
51 */
52 public class DeferredFileOutputStream extends ThresholdingOutputStream {
53
54 // @formatter:off
55 /**
56 * Builds a new {@link DeferredFileOutputStream}.
57 * <p>
58 * For example:
59 * </p>
60 * <pre>{@code
61 * DeferredFileOutputStream s = DeferredFileOutputStream.builder()
62 * .setBufferSize(4096)
63 * .setDirectory(dir)
64 * .setOutputFile(outputFile)
65 * .setPrefix(prefix)
66 * .setSuffix(suffix)
67 * .setThreshold(threshold)
68 * .get();}
69 * </pre>
70 * <p>
71 * The only super's aspect used us buffer size.
72 * </p>
73 *
74 * @see #get()
75 * @since 2.12.0
76 */
77 // @formatter:on
78 public static class Builder extends AbstractStreamBuilder<DeferredFileOutputStream, Builder> {
79
80 private int threshold;
81 private Path outputFile;
82 private String prefix;
83 private String suffix;
84 private Path directory;
85
86 /**
87 * Constructs a new builder.
88 */
89 public Builder() {
90 setBufferSizeDefault(AbstractByteArrayOutputStream.DEFAULT_SIZE);
91 setBufferSize(AbstractByteArrayOutputStream.DEFAULT_SIZE);
92 }
93
94 /**
95 * Builds a new {@link DeferredFileOutputStream}.
96 * <p>
97 * This builder use the following aspects:
98 * </p>
99 * <ul>
100 * <li>{@link #getBufferSize()}</li>
101 * <li>threshold</li>
102 * <li>outputFile</li>
103 * <li>prefix</li>
104 * <li>suffix</li>
105 * <li>directory</li>
106 * </ul>
107 *
108 * @return a new instance.
109 */
110 @Override
111 public DeferredFileOutputStream get() {
112 return new DeferredFileOutputStream(threshold, outputFile, prefix, suffix, directory, getBufferSize());
113 }
114
115 /**
116 * Sets the temporary file directory.
117 *
118 * @param directory Temporary file directory.
119 * @return this
120 */
121 public Builder setDirectory(final File directory) {
122 this.directory = toPath(directory, null);
123 return this;
124 }
125
126 /**
127 * Sets the temporary file directory.
128 *
129 * @param directory Temporary file directory.
130 * @return this
131 * @since 2.14.0
132 */
133 public Builder setDirectory(final Path directory) {
134 this.directory = toPath(directory, null);
135 return this;
136 }
137
138 /**
139 * Sets the file to which data is saved beyond the threshold.
140 *
141 * @param outputFile The file to which data is saved beyond the threshold.
142 * @return this
143 */
144 public Builder setOutputFile(final File outputFile) {
145 this.outputFile = toPath(outputFile, null);
146 return this;
147 }
148
149 /**
150 * Sets the file to which data is saved beyond the threshold.
151 *
152 * @param outputFile The file to which data is saved beyond the threshold.
153 * @return this
154 * @since 2.14.0
155 */
156 public Builder setOutputFile(final Path outputFile) {
157 this.outputFile = toPath(outputFile, null);
158 return this;
159 }
160
161 /**
162 * Sets the prefix to use for the temporary file.
163 *
164 * @param prefix Prefix to use for the temporary file.
165 * @return this
166 */
167 public Builder setPrefix(final String prefix) {
168 this.prefix = prefix;
169 return this;
170 }
171
172 /**
173 * Sets the suffix to use for the temporary file.
174 *
175 * @param suffix Suffix to use for the temporary file.
176 * @return this
177 */
178 public Builder setSuffix(final String suffix) {
179 this.suffix = suffix;
180 return this;
181 }
182
183 /**
184 * Sets the number of bytes at which to trigger an event.
185 *
186 * @param threshold The number of bytes at which to trigger an event.
187 * @return this
188 */
189 public Builder setThreshold(final int threshold) {
190 this.threshold = threshold;
191 return this;
192 }
193
194 }
195
196 /**
197 * Constructs a new {@link Builder}.
198 *
199 * @return a new {@link Builder}.
200 * @since 2.12.0
201 */
202 public static Builder builder() {
203 return new Builder();
204 }
205
206 private static int checkBufferSize(final int initialBufferSize) {
207 if (initialBufferSize < 0) {
208 throw new IllegalArgumentException("Initial buffer size must be at least 0.");
209 }
210 return initialBufferSize;
211 }
212
213 private static Path toPath(final File file, final Supplier<Path> defaultPathSupplier) {
214 return file != null ? file.toPath() : defaultPathSupplier == null ? null : defaultPathSupplier.get();
215 }
216
217 private static Path toPath(final Path file, final Supplier<Path> defaultPathSupplier) {
218 return file != null ? file : defaultPathSupplier == null ? null : defaultPathSupplier.get();
219 }
220
221 /**
222 * The output stream to which data will be written prior to the threshold being reached.
223 */
224 private ByteArrayOutputStream memoryOutputStream;
225
226 /**
227 * The output stream to which data will be written at any given time. This will always be one of {@code memoryOutputStream} or {@code diskOutputStream}.
228 */
229 private OutputStream currentOutputStream;
230
231 /**
232 * The file to which output will be directed if the threshold is exceeded.
233 */
234 private Path outputPath;
235
236 /**
237 * The temporary file prefix.
238 */
239 private final String prefix;
240
241 /**
242 * The temporary file suffix.
243 */
244 private final String suffix;
245
246 /**
247 * The directory to use for temporary files.
248 */
249 private final Path directory;
250
251 /**
252 * True when close() has been called successfully.
253 */
254 private boolean closed;
255
256 /**
257 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point. The initial
258 * buffer size will default to {@value AbstractByteArrayOutputStream#DEFAULT_SIZE} bytes which is ByteArrayOutputStream's default buffer size.
259 *
260 * @param threshold The number of bytes at which to trigger an event.
261 * @param outputFile The file to which data is saved beyond the threshold.
262 * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
263 */
264 @Deprecated
265 public DeferredFileOutputStream(final int threshold, final File outputFile) {
266 this(threshold, outputFile, null, null, null, AbstractByteArrayOutputStream.DEFAULT_SIZE);
267 }
268
269 /**
270 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data either to a file beyond that point.
271 *
272 * @param threshold The number of bytes at which to trigger an event.
273 * @param outputFile The file to which data is saved beyond the threshold.
274 * @param prefix Prefix to use for the temporary file.
275 * @param suffix Suffix to use for the temporary file.
276 * @param directory Temporary file directory.
277 * @param initialBufferSize The initial size of the in memory buffer.
278 * @throws IllegalArgumentException if initialBufferSize < 0.
279 */
280 private DeferredFileOutputStream(final int threshold, final File outputFile, final String prefix, final String suffix, final File directory,
281 final int initialBufferSize) {
282 super(threshold);
283 this.outputPath = toPath(outputFile, null);
284 this.prefix = prefix;
285 this.suffix = suffix;
286 this.directory = toPath(directory, PathUtils::getTempDirectory);
287 this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
288 this.currentOutputStream = memoryOutputStream;
289 }
290
291 /**
292 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point.
293 *
294 * @param threshold The number of bytes at which to trigger an event.
295 * @param initialBufferSize The initial size of the in memory buffer.
296 * @param outputFile The file to which data is saved beyond the threshold.
297 * @since 2.5
298 * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
299 */
300 @Deprecated
301 public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final File outputFile) {
302 this(threshold, outputFile, null, null, null, initialBufferSize);
303 }
304
305 /**
306 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a temporary file beyond that point.
307 *
308 * @param threshold The number of bytes at which to trigger an event.
309 * @param initialBufferSize The initial size of the in memory buffer.
310 * @param prefix Prefix to use for the temporary file.
311 * @param suffix Suffix to use for the temporary file.
312 * @param directory Temporary file directory.
313 * @since 2.5
314 * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
315 */
316 @Deprecated
317 public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final String prefix, final String suffix, final File directory) {
318 this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, initialBufferSize);
319 }
320
321 /**
322 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data either to a file beyond that point.
323 *
324 * @param threshold The number of bytes at which to trigger an event.
325 * @param outputFile The file to which data is saved beyond the threshold.
326 * @param prefix Prefix to use for the temporary file.
327 * @param suffix Suffix to use for the temporary file.
328 * @param directory Temporary file directory.
329 * @param initialBufferSize The initial size of the in memory buffer.
330 * @throws IllegalArgumentException if initialBufferSize < 0.
331 */
332 private DeferredFileOutputStream(final int threshold, final Path outputFile, final String prefix, final String suffix, final Path directory,
333 final int initialBufferSize) {
334 super(threshold);
335 this.outputPath = toPath(outputFile, null);
336 this.prefix = prefix;
337 this.suffix = suffix;
338 this.directory = toPath(directory, PathUtils::getTempDirectory);
339 this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
340 this.currentOutputStream = memoryOutputStream;
341 }
342
343 /**
344 * Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a temporary file beyond that point. The
345 * initial buffer size will default to 32 bytes which is ByteArrayOutputStream's default buffer size.
346 *
347 * @param threshold The number of bytes at which to trigger an event.
348 * @param prefix Prefix to use for the temporary file.
349 * @param suffix Suffix to use for the temporary file.
350 * @param directory Temporary file directory.
351 * @since 1.4
352 * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
353 */
354 @Deprecated
355 public DeferredFileOutputStream(final int threshold, final String prefix, final String suffix, final File directory) {
356 this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, AbstractByteArrayOutputStream.DEFAULT_SIZE);
357 }
358
359 /**
360 * Closes underlying output stream, and mark this as closed
361 *
362 * @throws IOException if an error occurs.
363 */
364 @Override
365 public void close() throws IOException {
366 super.close();
367 closed = true;
368 }
369
370 /**
371 * Gets the data for this output stream as an array of bytes, assuming that the data has been retained in memory. If the data was written to disk, this
372 * method returns {@code null}.
373 *
374 * @return The data for this output stream, or {@code null} if no such data is available.
375 */
376 public byte[] getData() {
377 return memoryOutputStream != null ? memoryOutputStream.toByteArray() : null;
378 }
379
380 /**
381 * Gets either the output File specified in the constructor or the temporary File created or null.
382 * <p>
383 * If the constructor specifying the File is used then it returns that same output File, even when threshold has not been reached.
384 * </p>
385 * <p>
386 * If constructor specifying a temporary File prefix/suffix is used then the temporary File created once the threshold is reached is returned if the
387 * threshold was not reached then {@code null} is returned.
388 * </p>
389 *
390 * @return The File for this output stream, or {@code null} if no such File exists.
391 */
392 public File getFile() {
393 return outputPath != null ? outputPath.toFile() : null;
394 }
395
396 /**
397 * Gets either the output Path specified in the constructor or the temporary Path created or null.
398 * <p>
399 * If the constructor specifying the file is used then it returns that same output Path, even when threshold has not been reached.
400 * </p>
401 * <p>
402 * If constructor specifying a temporary Path prefix/suffix is used then the temporary Path created once the threshold is reached is returned if the
403 * threshold was not reached then {@code null} is returned.
404 * </p>
405 *
406 * @return The Path for this output stream, or {@code null} if no such Path exists.
407 * @since 2.14.0
408 */
409 public Path getPath() {
410 return outputPath;
411 }
412
413 /**
414 * Gets the current output stream. This may be memory based or disk based, depending on the current state with respect to the threshold.
415 *
416 * @return The underlying output stream.
417 * @throws IOException if an error occurs.
418 */
419 @Override
420 protected OutputStream getStream() throws IOException {
421 return currentOutputStream;
422 }
423
424 /**
425 * Tests whether or not the data for this output stream has been retained in memory.
426 *
427 * @return {@code true} if the data is available in memory; {@code false} otherwise.
428 */
429 public boolean isInMemory() {
430 return !isThresholdExceeded();
431 }
432
433 /**
434 * Switches the underlying output stream from a memory based stream to one that is backed by disk. This is the point at which we realize that too much data
435 * is being written to keep in memory, so we elect to switch to disk-based storage.
436 *
437 * @throws IOException if an error occurs.
438 */
439 @Override
440 protected void thresholdReached() throws IOException {
441 if (prefix != null) {
442 outputPath = Files.createTempFile(directory, prefix, suffix);
443 }
444 PathUtils.createParentDirectories(outputPath, null, PathUtils.EMPTY_FILE_ATTRIBUTE_ARRAY);
445 final OutputStream fos = Files.newOutputStream(outputPath);
446 try {
447 memoryOutputStream.writeTo(fos);
448 } catch (final IOException e) {
449 fos.close();
450 throw e;
451 }
452 currentOutputStream = fos;
453 memoryOutputStream = null;
454 }
455
456 /**
457 * Converts the current contents of this byte stream to an {@link InputStream}. If the data for this output stream has been retained in memory, the returned
458 * stream is backed by buffers of {@code this} stream, avoiding memory allocation and copy, thus saving space and time.<br>
459 * Otherwise, the returned stream will be one that is created from the data that has been committed to disk.
460 *
461 * @return the current contents of this output stream.
462 * @throws IOException if this stream is not yet closed or an error occurs.
463 * @see org.apache.commons.io.output.ByteArrayOutputStream#toInputStream()
464 *
465 * @since 2.9.0
466 */
467 public InputStream toInputStream() throws IOException {
468 // we may only need to check if this is closed if we are working with a file
469 // but we should force the habit of closing whether we are working with
470 // a file or memory.
471 if (!closed) {
472 throw new IOException("Stream not closed");
473 }
474 if (isInMemory()) {
475 return memoryOutputStream.toInputStream();
476 }
477 return Files.newInputStream(outputPath);
478 }
479
480 /**
481 * Writes the data from this output stream to the specified output stream, after it has been closed.
482 *
483 * @param outputStream output stream to write to.
484 * @throws NullPointerException if the OutputStream is {@code null}.
485 * @throws IOException if this stream is not yet closed or an error occurs.
486 */
487 public void writeTo(final OutputStream outputStream) throws IOException {
488 // we may only need to check if this is closed if we are working with a file
489 // but we should force the habit of closing whether we are working with
490 // a file or memory.
491 if (!closed) {
492 throw new IOException("Stream not closed");
493 }
494 if (isInMemory()) {
495 memoryOutputStream.writeTo(outputStream);
496 } else {
497 Files.copy(outputPath, outputStream);
498 }
499 }
500 }