src/main/java/org/apache/commons/io/output/DeferredFileOutputStream.java - commons-io - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.commons.io.output;

 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Objects;
 import java.util.function.Supplier;

 import org.apache.commons.io.build.AbstractStreamBuilder;
 import org.apache.commons.io.file.PathUtils;

 /**
  * 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
  * threshold is reached, the data will not be written to disk at all.
  * <p>
  * To build an instance, use {@link Builder}.
  * </p>
  * <p>
  * The caller is responsible for deleting the output file ({@link #getFile()}, {@link #getPath()}) created by a DeferredFileOutputStream when the caller only
  * configured a prefix.
  * </p>
  * <p>
  * The caller is responsible for deleting the output file passed to a constructor or builder through {@link Builder#setOutputFile(File)} or
  * {@link Builder#setOutputFile(Path)}.
  * </p>
  * <p>
  * 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
  * 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).
  * </p>
  *
  * @see Builder
  */
 public class DeferredFileOutputStream extends ThresholdingOutputStream {

     // @formatter:off
     /**
      * Builds a new {@link DeferredFileOutputStream}.
      * <p>
      * For example:
      * </p>
      * <pre>{@code
      * DeferredFileOutputStream s = DeferredFileOutputStream.builder()
      *   .setBufferSize(4096)
      *   .setDirectory(dir)
      *   .setOutputFile(outputFile)
      *   .setPrefix(prefix)
      *   .setSuffix(suffix)
      *   .setThreshold(threshold)
      *   .get();}
      * </pre>
      * <p>
      * The only super's aspect used us buffer size.
      * </p>
      *
      * @see #get()
      * @since 2.12.0
      */
     // @formatter:on
     public static class Builder extends AbstractStreamBuilder<DeferredFileOutputStream, Builder> {

         private int threshold;
         private Path outputFile;
         private String prefix;
         private String suffix;
         private Path directory;

         /**
          * Constructs a new builder.
          */
         public Builder() {
             setBufferSizeDefault(AbstractByteArrayOutputStream.DEFAULT_SIZE);
             setBufferSize(AbstractByteArrayOutputStream.DEFAULT_SIZE);
         }

         /**
          * Builds a new {@link DeferredFileOutputStream}.
          * <p>
          * This builder use the following aspects:
          * </p>
          * <ul>
          * <li>{@link #getBufferSize()}</li>
          * <li>threshold</li>
          * <li>outputFile</li>
          * <li>prefix</li>
          * <li>suffix</li>
          * <li>directory</li>
          * </ul>
          *
          * @return a new instance.
          */
         @Override
         public DeferredFileOutputStream get() {
             return new DeferredFileOutputStream(threshold, outputFile, prefix, suffix, directory, getBufferSize());
         }

         /**
          * Sets the temporary file directory.
          *
          * @param directory Temporary file directory.
          * @return this
          */
         public Builder setDirectory(final File directory) {
             this.directory = toPath(directory, null);
             return this;
         }

         /**
          * Sets the temporary file directory.
          *
          * @param directory Temporary file directory.
          * @return this
          * @since 2.14.0
          */
         public Builder setDirectory(final Path directory) {
             this.directory = toPath(directory, null);
             return this;
         }

         /**
          * Sets the file to which data is saved beyond the threshold.
          *
          * @param outputFile The file to which data is saved beyond the threshold.
          * @return this
          */
         public Builder setOutputFile(final File outputFile) {
             this.outputFile = toPath(outputFile, null);
             return this;
         }

         /**
          * Sets the file to which data is saved beyond the threshold.
          *
          * @param outputFile The file to which data is saved beyond the threshold.
          * @return this
          * @since 2.14.0
          */
         public Builder setOutputFile(final Path outputFile) {
             this.outputFile = toPath(outputFile, null);
             return this;
         }

         /**
          * Sets the prefix to use for the temporary file.
          *
          * @param prefix Prefix to use for the temporary file.
          * @return this
          */
         public Builder setPrefix(final String prefix) {
             this.prefix = prefix;
             return this;
         }

         /**
          * Sets the suffix to use for the temporary file.
          *
          * @param suffix Suffix to use for the temporary file.
          * @return this
          */
         public Builder setSuffix(final String suffix) {
             this.suffix = suffix;
             return this;
         }

         /**
          * Sets the number of bytes at which to trigger an event.
          *
          * @param threshold The number of bytes at which to trigger an event.
          * @return this
          */
         public Builder setThreshold(final int threshold) {
             this.threshold = threshold;
             return this;
         }

     }

     /**
      * Constructs a new {@link Builder}.
      *
      * @return a new {@link Builder}.
      * @since 2.12.0
      */
     public static Builder builder() {
         return new Builder();
     }

     private static int checkBufferSize(final int initialBufferSize) {
         if (initialBufferSize < 0) {
             throw new IllegalArgumentException("Initial buffer size must be at least 0.");
         }
         return initialBufferSize;
     }

     private static Path toPath(final File file, final Supplier<Path> defaultPathSupplier) {
         return file != null ? file.toPath() : defaultPathSupplier == null ? null : defaultPathSupplier.get();
     }

     private static Path toPath(final Path file, final Supplier<Path> defaultPathSupplier) {
         return file != null ? file : defaultPathSupplier == null ? null : defaultPathSupplier.get();
     }

     /**
      * The output stream to which data will be written prior to the threshold being reached.
      */
     private ByteArrayOutputStream memoryOutputStream;

     /**
      * The output stream to which data will be written at any given time. This will always be one of {@code memoryOutputStream} or {@code diskOutputStream}.
      */
     private OutputStream currentOutputStream;

     /**
      * The file to which output will be directed if the threshold is exceeded.
      */
     private Path outputPath;

     /**
      * The temporary file prefix.
      */
     private final String prefix;

     /**
      * The temporary file suffix.
      */
     private final String suffix;

     /**
      * The directory to use for temporary files.
      */
     private final Path directory;

     /**
      * True when close() has been called successfully.
      */
     private boolean closed;

     /**
      * 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
      * buffer size will default to {@value AbstractByteArrayOutputStream#DEFAULT_SIZE} bytes which is ByteArrayOutputStream's default buffer size.
      *
      * @param threshold  The number of bytes at which to trigger an event.
      * @param outputFile The file to which data is saved beyond the threshold.
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public DeferredFileOutputStream(final int threshold, final File outputFile) {
         this(threshold, outputFile, null, null, null, AbstractByteArrayOutputStream.DEFAULT_SIZE);
     }

     /**
      * 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.
      *
      * @param threshold         The number of bytes at which to trigger an event.
      * @param outputFile        The file to which data is saved beyond the threshold.
      * @param prefix            Prefix to use for the temporary file.
      * @param suffix            Suffix to use for the temporary file.
      * @param directory         Temporary file directory.
      * @param initialBufferSize The initial size of the in memory buffer.
      * @throws IllegalArgumentException if initialBufferSize &lt; 0.
      */
     private DeferredFileOutputStream(final int threshold, final File outputFile, final String prefix, final String suffix, final File directory,
             final int initialBufferSize) {
         super(threshold);
         this.outputPath = toPath(outputFile, null);
         this.prefix = prefix;
         this.suffix = suffix;
         this.directory = toPath(directory, PathUtils::getTempDirectory);
         this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
         this.currentOutputStream = memoryOutputStream;
     }

     /**
      * Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point.
      *
      * @param threshold         The number of bytes at which to trigger an event.
      * @param initialBufferSize The initial size of the in memory buffer.
      * @param outputFile        The file to which data is saved beyond the threshold.
      * @since 2.5
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final File outputFile) {
         this(threshold, outputFile, null, null, null, initialBufferSize);
     }

     /**
      * 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.
      *
      * @param threshold         The number of bytes at which to trigger an event.
      * @param initialBufferSize The initial size of the in memory buffer.
      * @param prefix            Prefix to use for the temporary file.
      * @param suffix            Suffix to use for the temporary file.
      * @param directory         Temporary file directory.
      * @since 2.5
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final String prefix, final String suffix, final File directory) {
         this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, initialBufferSize);
     }

     /**
      * 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.
      *
      * @param threshold         The number of bytes at which to trigger an event.
      * @param outputFile        The file to which data is saved beyond the threshold.
      * @param prefix            Prefix to use for the temporary file.
      * @param suffix            Suffix to use for the temporary file.
      * @param directory         Temporary file directory.
      * @param initialBufferSize The initial size of the in memory buffer.
      * @throws IllegalArgumentException if initialBufferSize &lt; 0.
      */
     private DeferredFileOutputStream(final int threshold, final Path outputFile, final String prefix, final String suffix, final Path directory,
             final int initialBufferSize) {
         super(threshold);
         this.outputPath = toPath(outputFile, null);
         this.prefix = prefix;
         this.suffix = suffix;
         this.directory = toPath(directory, PathUtils::getTempDirectory);
         this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
         this.currentOutputStream = memoryOutputStream;
     }

     /**
      * 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
      * initial buffer size will default to 32 bytes which is ByteArrayOutputStream's default buffer size.
      *
      * @param threshold The number of bytes at which to trigger an event.
      * @param prefix    Prefix to use for the temporary file.
      * @param suffix    Suffix to use for the temporary file.
      * @param directory Temporary file directory.
      * @since 1.4
      * @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
      */
     @Deprecated
     public DeferredFileOutputStream(final int threshold, final String prefix, final String suffix, final File directory) {
         this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, AbstractByteArrayOutputStream.DEFAULT_SIZE);
     }

     /**
      * Closes underlying output stream, and mark this as closed
      *
      * @throws IOException if an error occurs.
      */
     @Override
     public void close() throws IOException {
         super.close();
         closed = true;
     }

     /**
      * 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
      * method returns {@code null}.
      *
      * @return The data for this output stream, or {@code null} if no such data is available.
      */
     public byte[] getData() {
         return memoryOutputStream != null ? memoryOutputStream.toByteArray() : null;
     }

     /**
      * Gets either the output File specified in the constructor or the temporary File created or null.
      * <p>
      * If the constructor specifying the File is used then it returns that same output File, even when threshold has not been reached.
      * </p>
      * <p>
      * If constructor specifying a temporary File prefix/suffix is used then the temporary File created once the threshold is reached is returned if the
      * threshold was not reached then {@code null} is returned.
      * </p>
      *
      * @return The File for this output stream, or {@code null} if no such File exists.
      */
     public File getFile() {
         return outputPath != null ? outputPath.toFile() : null;
     }

     /**
      * Gets either the output Path specified in the constructor or the temporary Path created or null.
      * <p>
      * If the constructor specifying the file is used then it returns that same output Path, even when threshold has not been reached.
      * </p>
      * <p>
      * If constructor specifying a temporary Path prefix/suffix is used then the temporary Path created once the threshold is reached is returned if the
      * threshold was not reached then {@code null} is returned.
      * </p>
      *
      * @return The Path for this output stream, or {@code null} if no such Path exists.
      * @since 2.14.0
      */
     public Path getPath() {
         return outputPath;
     }

     /**
      * Gets the current output stream. This may be memory based or disk based, depending on the current state with respect to the threshold.
      *
      * @return The underlying output stream.
      * @throws IOException if an error occurs.
      */
     @Override
     protected OutputStream getStream() throws IOException {
         return currentOutputStream;
     }

     /**
      * Tests whether or not the data for this output stream has been retained in memory.
      *
      * @return {@code true} if the data is available in memory; {@code false} otherwise.
      */
     public boolean isInMemory() {
         return !isThresholdExceeded();
     }

     /**
      * 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
      * is being written to keep in memory, so we elect to switch to disk-based storage.
      *
      * @throws IOException if an error occurs.
      */
     @Override
     protected void thresholdReached() throws IOException {
         if (prefix != null) {
             outputPath = Files.createTempFile(directory, prefix, suffix);
         }
         PathUtils.createParentDirectories(outputPath, null, PathUtils.EMPTY_FILE_ATTRIBUTE_ARRAY);
         final OutputStream fos = Files.newOutputStream(outputPath);
         try {
             memoryOutputStream.writeTo(fos);
         } catch (final IOException e) {
             fos.close();
             throw e;
         }
         currentOutputStream = fos;
         memoryOutputStream = null;
     }

     /**
      * 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
      * stream is backed by buffers of {@code this} stream, avoiding memory allocation and copy, thus saving space and time.<br>
      * Otherwise, the returned stream will be one that is created from the data that has been committed to disk.
      *
      * @return the current contents of this output stream.
      * @throws IOException if this stream is not yet closed or an error occurs.
      * @see org.apache.commons.io.output.ByteArrayOutputStream#toInputStream()
      *
      * @since 2.9.0
      */
     public InputStream toInputStream() throws IOException {
         // we may only need to check if this is closed if we are working with a file
         // but we should force the habit of closing whether we are working with
         // a file or memory.
         if (!closed) {
             throw new IOException("Stream not closed");
         }
         if (isInMemory()) {
             return memoryOutputStream.toInputStream();
         }
         return Files.newInputStream(outputPath);
     }

     /**
      * Writes the data from this output stream to the specified output stream, after it has been closed.
      *
      * @param outputStream output stream to write to.
      * @throws NullPointerException if the OutputStream is {@code null}.
      * @throws IOException          if this stream is not yet closed or an error occurs.
      */
     public void writeTo(final OutputStream outputStream) throws IOException {
         // we may only need to check if this is closed if we are working with a file
         // but we should force the habit of closing whether we are working with
         // a file or memory.
         if (!closed) {
             throw new IOException("Stream not closed");
         }
         if (isInMemory()) {
             memoryOutputStream.writeTo(outputStream);
         } else {
             Files.copy(outputPath, outputStream);
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.commons.io.output;

	import java.io.File;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.nio.file.Files;
	import java.nio.file.Path;
	import java.util.Objects;
	import java.util.function.Supplier;

	import org.apache.commons.io.build.AbstractStreamBuilder;
	import org.apache.commons.io.file.PathUtils;

	/**
	* 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
	* threshold is reached, the data will not be written to disk at all.
	* <p>
	* To build an instance, use {@link Builder}.
	* </p>
	* <p>
	* The caller is responsible for deleting the output file ({@link #getFile()}, {@link #getPath()}) created by a DeferredFileOutputStream when the caller only
	* configured a prefix.
	* </p>
	* <p>
	* The caller is responsible for deleting the output file passed to a constructor or builder through {@link Builder#setOutputFile(File)} or
	* {@link Builder#setOutputFile(Path)}.
	* </p>
	* <p>
	* 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
	* 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).
	* </p>
	*
	* @see Builder
	*/
	public class DeferredFileOutputStream extends ThresholdingOutputStream {

	// @formatter:off
	/**
	* Builds a new {@link DeferredFileOutputStream}.
	* <p>
	* For example:
	* </p>
	* <pre>{@code
	* DeferredFileOutputStream s = DeferredFileOutputStream.builder()
	* .setBufferSize(4096)
	* .setDirectory(dir)
	* .setOutputFile(outputFile)
	* .setPrefix(prefix)
	* .setSuffix(suffix)
	* .setThreshold(threshold)
	* .get();}
	* </pre>
	* <p>
	* The only super's aspect used us buffer size.
	* </p>
	*
	* @see #get()
	* @since 2.12.0
	*/
	// @formatter:on
	public static class Builder extends AbstractStreamBuilder<DeferredFileOutputStream, Builder> {

	private int threshold;
	private Path outputFile;
	private String prefix;
	private String suffix;
	private Path directory;

	/**
	* Constructs a new builder.
	*/
	public Builder() {
	setBufferSizeDefault(AbstractByteArrayOutputStream.DEFAULT_SIZE);
	setBufferSize(AbstractByteArrayOutputStream.DEFAULT_SIZE);
	}

	/**
	* Builds a new {@link DeferredFileOutputStream}.
	* <p>
	* This builder use the following aspects:
	* </p>
	* <ul>
	* <li>{@link #getBufferSize()}</li>
	* <li>threshold</li>
	* <li>outputFile</li>
	* <li>prefix</li>
	* <li>suffix</li>
	* <li>directory</li>
	* </ul>
	*
	* @return a new instance.
	*/
	@Override
	public DeferredFileOutputStream get() {
	return new DeferredFileOutputStream(threshold, outputFile, prefix, suffix, directory, getBufferSize());
	}

	/**
	* Sets the temporary file directory.
	*
	* @param directory Temporary file directory.
	* @return this
	*/
	public Builder setDirectory(final File directory) {
	this.directory = toPath(directory, null);
	return this;
	}

	/**
	* Sets the temporary file directory.
	*
	* @param directory Temporary file directory.
	* @return this
	* @since 2.14.0
	*/
	public Builder setDirectory(final Path directory) {
	this.directory = toPath(directory, null);
	return this;
	}

	/**
	* Sets the file to which data is saved beyond the threshold.
	*
	* @param outputFile The file to which data is saved beyond the threshold.
	* @return this
	*/
	public Builder setOutputFile(final File outputFile) {
	this.outputFile = toPath(outputFile, null);
	return this;
	}

	/**
	* Sets the file to which data is saved beyond the threshold.
	*
	* @param outputFile The file to which data is saved beyond the threshold.
	* @return this
	* @since 2.14.0
	*/
	public Builder setOutputFile(final Path outputFile) {
	this.outputFile = toPath(outputFile, null);
	return this;
	}

	/**
	* Sets the prefix to use for the temporary file.
	*
	* @param prefix Prefix to use for the temporary file.
	* @return this
	*/
	public Builder setPrefix(final String prefix) {
	this.prefix = prefix;
	return this;
	}

	/**
	* Sets the suffix to use for the temporary file.
	*
	* @param suffix Suffix to use for the temporary file.
	* @return this
	*/
	public Builder setSuffix(final String suffix) {
	this.suffix = suffix;
	return this;
	}

	/**
	* Sets the number of bytes at which to trigger an event.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @return this
	*/
	public Builder setThreshold(final int threshold) {
	this.threshold = threshold;
	return this;
	}

	}

	/**
	* Constructs a new {@link Builder}.
	*
	* @return a new {@link Builder}.
	* @since 2.12.0
	*/
	public static Builder builder() {
	return new Builder();
	}

	private static int checkBufferSize(final int initialBufferSize) {
	if (initialBufferSize < 0) {
	throw new IllegalArgumentException("Initial buffer size must be at least 0.");
	}
	return initialBufferSize;
	}

	private static Path toPath(final File file, final Supplier<Path> defaultPathSupplier) {
	return file != null ? file.toPath() : defaultPathSupplier == null ? null : defaultPathSupplier.get();
	}

	private static Path toPath(final Path file, final Supplier<Path> defaultPathSupplier) {
	return file != null ? file : defaultPathSupplier == null ? null : defaultPathSupplier.get();
	}

	/**
	* The output stream to which data will be written prior to the threshold being reached.
	*/
	private ByteArrayOutputStream memoryOutputStream;

	/**
	* The output stream to which data will be written at any given time. This will always be one of {@code memoryOutputStream} or {@code diskOutputStream}.
	*/
	private OutputStream currentOutputStream;

	/**
	* The file to which output will be directed if the threshold is exceeded.
	*/
	private Path outputPath;

	/**
	* The temporary file prefix.
	*/
	private final String prefix;

	/**
	* The temporary file suffix.
	*/
	private final String suffix;

	/**
	* The directory to use for temporary files.
	*/
	private final Path directory;

	/**
	* True when close() has been called successfully.
	*/
	private boolean closed;

	/**
	* 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
	* buffer size will default to {@value AbstractByteArrayOutputStream#DEFAULT_SIZE} bytes which is ByteArrayOutputStream's default buffer size.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param outputFile The file to which data is saved beyond the threshold.
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public DeferredFileOutputStream(final int threshold, final File outputFile) {
	this(threshold, outputFile, null, null, null, AbstractByteArrayOutputStream.DEFAULT_SIZE);
	}

	/**
	* 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.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param outputFile The file to which data is saved beyond the threshold.
	* @param prefix Prefix to use for the temporary file.
	* @param suffix Suffix to use for the temporary file.
	* @param directory Temporary file directory.
	* @param initialBufferSize The initial size of the in memory buffer.
	* @throws IllegalArgumentException if initialBufferSize < 0.
	*/
	private DeferredFileOutputStream(final int threshold, final File outputFile, final String prefix, final String suffix, final File directory,
	final int initialBufferSize) {
	super(threshold);
	this.outputPath = toPath(outputFile, null);
	this.prefix = prefix;
	this.suffix = suffix;
	this.directory = toPath(directory, PathUtils::getTempDirectory);
	this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
	this.currentOutputStream = memoryOutputStream;
	}

	/**
	* Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param initialBufferSize The initial size of the in memory buffer.
	* @param outputFile The file to which data is saved beyond the threshold.
	* @since 2.5
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final File outputFile) {
	this(threshold, outputFile, null, null, null, initialBufferSize);
	}

	/**
	* 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.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param initialBufferSize The initial size of the in memory buffer.
	* @param prefix Prefix to use for the temporary file.
	* @param suffix Suffix to use for the temporary file.
	* @param directory Temporary file directory.
	* @since 2.5
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public DeferredFileOutputStream(final int threshold, final int initialBufferSize, final String prefix, final String suffix, final File directory) {
	this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, initialBufferSize);
	}

	/**
	* 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.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param outputFile The file to which data is saved beyond the threshold.
	* @param prefix Prefix to use for the temporary file.
	* @param suffix Suffix to use for the temporary file.
	* @param directory Temporary file directory.
	* @param initialBufferSize The initial size of the in memory buffer.
	* @throws IllegalArgumentException if initialBufferSize < 0.
	*/
	private DeferredFileOutputStream(final int threshold, final Path outputFile, final String prefix, final String suffix, final Path directory,
	final int initialBufferSize) {
	super(threshold);
	this.outputPath = toPath(outputFile, null);
	this.prefix = prefix;
	this.suffix = suffix;
	this.directory = toPath(directory, PathUtils::getTempDirectory);
	this.memoryOutputStream = new ByteArrayOutputStream(checkBufferSize(initialBufferSize));
	this.currentOutputStream = memoryOutputStream;
	}

	/**
	* 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
	* initial buffer size will default to 32 bytes which is ByteArrayOutputStream's default buffer size.
	*
	* @param threshold The number of bytes at which to trigger an event.
	* @param prefix Prefix to use for the temporary file.
	* @param suffix Suffix to use for the temporary file.
	* @param directory Temporary file directory.
	* @since 1.4
	* @deprecated Use {@link #builder()}, {@link Builder}, and {@link Builder#get()}
	*/
	@Deprecated
	public DeferredFileOutputStream(final int threshold, final String prefix, final String suffix, final File directory) {
	this(threshold, null, Objects.requireNonNull(prefix, "prefix"), suffix, directory, AbstractByteArrayOutputStream.DEFAULT_SIZE);
	}

	/**
	* Closes underlying output stream, and mark this as closed
	*
	* @throws IOException if an error occurs.
	*/
	@Override
	public void close() throws IOException {
	super.close();
	closed = true;
	}

	/**
	* 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
	* method returns {@code null}.
	*
	* @return The data for this output stream, or {@code null} if no such data is available.
	*/
	public byte[] getData() {
	return memoryOutputStream != null ? memoryOutputStream.toByteArray() : null;
	}

	/**
	* Gets either the output File specified in the constructor or the temporary File created or null.
	* <p>
	* If the constructor specifying the File is used then it returns that same output File, even when threshold has not been reached.
	* </p>
	* <p>
	* If constructor specifying a temporary File prefix/suffix is used then the temporary File created once the threshold is reached is returned if the
	* threshold was not reached then {@code null} is returned.
	* </p>
	*
	* @return The File for this output stream, or {@code null} if no such File exists.
	*/
	public File getFile() {
	return outputPath != null ? outputPath.toFile() : null;
	}

	/**
	* Gets either the output Path specified in the constructor or the temporary Path created or null.
	* <p>
	* If the constructor specifying the file is used then it returns that same output Path, even when threshold has not been reached.
	* </p>
	* <p>
	* If constructor specifying a temporary Path prefix/suffix is used then the temporary Path created once the threshold is reached is returned if the
	* threshold was not reached then {@code null} is returned.
	* </p>
	*
	* @return The Path for this output stream, or {@code null} if no such Path exists.
	* @since 2.14.0
	*/
	public Path getPath() {
	return outputPath;
	}

	/**
	* Gets the current output stream. This may be memory based or disk based, depending on the current state with respect to the threshold.
	*
	* @return The underlying output stream.
	* @throws IOException if an error occurs.
	*/
	@Override
	protected OutputStream getStream() throws IOException {
	return currentOutputStream;
	}

	/**
	* Tests whether or not the data for this output stream has been retained in memory.
	*
	* @return {@code true} if the data is available in memory; {@code false} otherwise.
	*/
	public boolean isInMemory() {
	return !isThresholdExceeded();
	}

	/**
	* 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
	* is being written to keep in memory, so we elect to switch to disk-based storage.
	*
	* @throws IOException if an error occurs.
	*/
	@Override
	protected void thresholdReached() throws IOException {
	if (prefix != null) {
	outputPath = Files.createTempFile(directory, prefix, suffix);
	}
	PathUtils.createParentDirectories(outputPath, null, PathUtils.EMPTY_FILE_ATTRIBUTE_ARRAY);
	final OutputStream fos = Files.newOutputStream(outputPath);
	try {
	memoryOutputStream.writeTo(fos);
	} catch (final IOException e) {
	fos.close();
	throw e;
	}
	currentOutputStream = fos;
	memoryOutputStream = null;
	}

	/**
	* 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
	* stream is backed by buffers of {@code this} stream, avoiding memory allocation and copy, thus saving space and time.<br>
	* Otherwise, the returned stream will be one that is created from the data that has been committed to disk.
	*
	* @return the current contents of this output stream.
	* @throws IOException if this stream is not yet closed or an error occurs.
	* @see org.apache.commons.io.output.ByteArrayOutputStream#toInputStream()
	*
	* @since 2.9.0
	*/
	public InputStream toInputStream() throws IOException {
	// we may only need to check if this is closed if we are working with a file
	// but we should force the habit of closing whether we are working with
	// a file or memory.
	if (!closed) {
	throw new IOException("Stream not closed");
	}
	if (isInMemory()) {
	return memoryOutputStream.toInputStream();
	}
	return Files.newInputStream(outputPath);
	}

	/**
	* Writes the data from this output stream to the specified output stream, after it has been closed.
	*
	* @param outputStream output stream to write to.
	* @throws NullPointerException if the OutputStream is {@code null}.
	* @throws IOException if this stream is not yet closed or an error occurs.
	*/
	public void writeTo(final OutputStream outputStream) throws IOException {
	// we may only need to check if this is closed if we are working with a file
	// but we should force the habit of closing whether we are working with
	// a file or memory.
	if (!closed) {
	throw new IOException("Stream not closed");
	}
	if (isInMemory()) {
	memoryOutputStream.writeTo(outputStream);
	} else {
	Files.copy(outputPath, outputStream);
	}
	}
	}