public class DeferredFileOutputStream extends ThresholdingOutputStream
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).
Constructor and Description |
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DeferredFileOutputStream(int threshold,
File outputFile)
Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a
file beyond that point.
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DeferredFileOutputStream(int threshold,
int initialBufferSize,
File outputFile)
Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a
file beyond that point.
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DeferredFileOutputStream(int threshold,
int initialBufferSize,
String prefix,
String suffix,
File directory)
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.
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DeferredFileOutputStream(int threshold,
String prefix,
String suffix,
File directory)
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.
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Modifier and Type | Method and Description |
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void |
close()
Closes underlying output stream, and mark this as closed
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byte[] |
getData()
Returns the data for this output stream as an array of bytes, assuming that the data has been retained in memory.
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File |
getFile()
Returns either the output file specified in the constructor or the temporary file created or null.
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protected OutputStream |
getStream()
Returns the current output stream.
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boolean |
isInMemory()
Determines whether or not the data for this output stream has been retained in memory.
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protected void |
thresholdReached()
Switches the underlying output stream from a memory based stream to one that is backed by disk.
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InputStream |
toInputStream()
Gets the current contents of this byte stream as an
InputStream . |
void |
writeTo(OutputStream outputStream)
Writes the data from this output stream to the specified output stream, after it has been closed.
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checkThreshold, flush, getByteCount, getThreshold, isThresholdExceeded, resetByteCount, setByteCount, write, write, write
public DeferredFileOutputStream(int threshold, File outputFile)
threshold
- The number of bytes at which to trigger an event.outputFile
- The file to which data is saved beyond the threshold.public DeferredFileOutputStream(int threshold, int initialBufferSize, File outputFile)
threshold
- The number of bytes at which to trigger an event.initialBufferSize
- The initial size of the in memory buffer.outputFile
- The file to which data is saved beyond the threshold.public DeferredFileOutputStream(int threshold, int initialBufferSize, String prefix, String suffix, File directory)
threshold
- The number of bytes at which to trigger an event.initialBufferSize
- The initial size of the in memory buffer.prefix
- Prefix to use for the temporary file.suffix
- Suffix to use for the temporary file.directory
- Temporary file directory.public DeferredFileOutputStream(int threshold, String prefix, String suffix, File directory)
threshold
- The number of bytes at which to trigger an event.prefix
- Prefix to use for the temporary file.suffix
- Suffix to use for the temporary file.directory
- Temporary file directory.public void close() throws IOException
close
in interface Closeable
close
in interface AutoCloseable
close
in class ThresholdingOutputStream
IOException
- if an error occurs.public byte[] getData()
null
.null
if no such data is available.public File getFile()
If the constructor specifying the file is used then it returns that same output file, even when threshold has not been reached.
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 null
is returned.
null
if no such file exists.protected OutputStream getStream() throws IOException
getStream
in class ThresholdingOutputStream
IOException
- if an error occurs.public boolean isInMemory()
true
if the data is available in memory; false
otherwise.protected void thresholdReached() throws IOException
thresholdReached
in class ThresholdingOutputStream
IOException
- if an error occurs.public InputStream toInputStream() throws IOException
InputStream
.
If the data for this output stream has been retained in memory, the
returned stream is backed by buffers of this
stream,
avoiding memory allocation and copy, thus saving space and time.IOException
- if this stream is not yet closed or an error occurs.ByteArrayOutputStream.toInputStream()
public void writeTo(OutputStream outputStream) throws IOException
outputStream
- output stream to write to.NullPointerException
- if the OutputStream is null
.IOException
- if this stream is not yet closed or an error occurs.Copyright © 2002–2021 The Apache Software Foundation. All rights reserved.