Package com.google.common.io
Class FileBackedOutputStream
- java.lang.Object
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- java.io.OutputStream
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- com.google.common.io.FileBackedOutputStream
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- All Implemented Interfaces:
java.io.Closeable
,java.io.Flushable
,java.lang.AutoCloseable
@Beta @GwtIncompatible @J2ObjCIncompatible public final class FileBackedOutputStream extends java.io.OutputStream
AnOutputStream
that starts buffering to a byte array, but switches to file buffering once the data reaches a configurable size.When this stream creates a temporary file, it restricts the file's permissions to the current user or, in the case of Android, the current app. If that is not possible (as is the case under the very old Android Ice Cream Sandwich release), then this stream throws an exception instead of creating a file that would be more accessible. (This behavior is new in Guava 32.0.0. Previous versions would create a file that is more accessible, as discussed in Guava issue 2575. TODO: b/283778848 - Fill in CVE number once it's available.)
Temporary files created by this stream may live in the local filesystem until either:
reset()
is called (removing the data in this stream and deleting the file), or...- this stream (or, more precisely, its
asByteSource()
view) is finalized during garbage collection, AND this stream was not constructed with the 1-arg constructor or the 2-arg constructor passingfalse
in the second parameter.
This class is thread-safe.
- Since:
- 1.0
- Author:
- Chris Nokleberg
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Constructor Summary
Constructors Constructor Description FileBackedOutputStream(int fileThreshold)
Creates a new instance that uses the given file threshold, and does not reset the data when theByteSource
returned byasByteSource()
is finalized.FileBackedOutputStream(int fileThreshold, boolean resetOnFinalize)
Creates a new instance that uses the given file threshold, and optionally resets the data when theByteSource
returned byasByteSource()
is finalized.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ByteSource
asByteSource()
Returns a readableByteSource
view of the data that has been written to this stream.void
close()
void
flush()
void
reset()
Callsclose()
if not already closed, and then resets this object back to its initial state, for reuse.void
write(byte[] b)
void
write(byte[] b, int off, int len)
void
write(int b)
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Constructor Detail
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FileBackedOutputStream
public FileBackedOutputStream(int fileThreshold)
Creates a new instance that uses the given file threshold, and does not reset the data when theByteSource
returned byasByteSource()
is finalized.- Parameters:
fileThreshold
- the number of bytes before the stream should switch to buffering to a file- Throws:
java.lang.IllegalArgumentException
- iffileThreshold
is negative
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FileBackedOutputStream
public FileBackedOutputStream(int fileThreshold, boolean resetOnFinalize)
Creates a new instance that uses the given file threshold, and optionally resets the data when theByteSource
returned byasByteSource()
is finalized.- Parameters:
fileThreshold
- the number of bytes before the stream should switch to buffering to a fileresetOnFinalize
- if true, thereset()
method will be called when theByteSource
returned byasByteSource()
is finalized.- Throws:
java.lang.IllegalArgumentException
- iffileThreshold
is negative
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Method Detail
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asByteSource
public ByteSource asByteSource()
Returns a readableByteSource
view of the data that has been written to this stream.- Since:
- 15.0
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reset
public void reset() throws java.io.IOException
Callsclose()
if not already closed, and then resets this object back to its initial state, for reuse. If data was buffered to a file, it will be deleted.- Throws:
java.io.IOException
- if an I/O error occurred while deleting the file buffer
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write
public void write(int b) throws java.io.IOException
- Specified by:
write
in classjava.io.OutputStream
- Throws:
java.io.IOException
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write
public void write(byte[] b) throws java.io.IOException
- Overrides:
write
in classjava.io.OutputStream
- Throws:
java.io.IOException
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write
public void write(byte[] b, int off, int len) throws java.io.IOException
- Overrides:
write
in classjava.io.OutputStream
- Throws:
java.io.IOException
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close
public void close() throws java.io.IOException
- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Overrides:
close
in classjava.io.OutputStream
- Throws:
java.io.IOException
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flush
public void flush() throws java.io.IOException
- Specified by:
flush
in interfacejava.io.Flushable
- Overrides:
flush
in classjava.io.OutputStream
- Throws:
java.io.IOException
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