@Beta @GwtIncompatible public final class FileBackedOutputStream extends OutputStream
OutputStream
that starts buffering to a byte array, but switches to file buffering
once the data reaches a configurable size.
This class is thread-safe.
Constructor and Description |
---|
FileBackedOutputStream(int fileThreshold)
Creates a new instance that uses the given file threshold, and does not reset the data when the
ByteSource returned by asByteSource() is finalized. |
FileBackedOutputStream(int fileThreshold,
boolean resetOnFinalize)
Creates a new instance that uses the given file threshold, and optionally resets the data when
the
ByteSource returned by asByteSource() is finalized. |
Modifier and Type | Method and Description |
---|---|
ByteSource |
asByteSource()
Returns a readable
ByteSource view of the data that has been written to this stream. |
void |
close()
Closes this output stream and releases any system resources
associated with this stream.
|
void |
flush()
Flushes this output stream and forces any buffered output bytes
to be written out.
|
void |
reset()
Calls
close() if not already closed, and then resets this object back to its initial
state, for reuse. |
void |
write(byte[] b)
Writes
b.length bytes from the specified byte array
to this output stream. |
void |
write(byte[] b,
int off,
int len)
Writes
len bytes from the specified byte array
starting at offset off to this output stream. |
void |
write(int b)
Writes the specified byte to this output stream.
|
public FileBackedOutputStream(int fileThreshold)
ByteSource
returned by asByteSource()
is finalized.fileThreshold
- the number of bytes before the stream should switch to buffering to a filepublic FileBackedOutputStream(int fileThreshold, boolean resetOnFinalize)
ByteSource
returned by asByteSource()
is finalized.fileThreshold
- the number of bytes before the stream should switch to buffering to a fileresetOnFinalize
- if true, the reset()
method will be called when the ByteSource
returned by asByteSource()
is finalizedpublic ByteSource asByteSource()
ByteSource
view of the data that has been written to this stream.public void reset() throws IOException
close()
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.IOException
- if an I/O error occurred while deleting the file bufferpublic void write(int b) throws IOException
java.io.OutputStream
write
is that one byte is written
to the output stream. The byte to be written is the eight
low-order bits of the argument b
. The 24
high-order bits of b
are ignored.
Subclasses of OutputStream
must provide an
implementation for this method.
write
in class OutputStream
b
- the byte
.IOException
- if an I/O error occurs. In particular,
an IOException
may be thrown if the
output stream has been closed.public void write(byte[] b) throws IOException
java.io.OutputStream
b.length
bytes from the specified byte array
to this output stream. The general contract for write(b)
is that it should have exactly the same effect as the call
write(b, 0, b.length)
.write
in class OutputStream
b
- the data.IOException
- if an I/O error occurs.OutputStream.write(byte[], int, int)
public void write(byte[] b, int off, int len) throws IOException
java.io.OutputStream
len
bytes from the specified byte array
starting at offset off
to this output stream.
The general contract for write(b, off, len)
is that
some of the bytes in the array b
are written to the
output stream in order; element b[off]
is the first
byte written and b[off+len-1]
is the last byte written
by this operation.
The write
method of OutputStream
calls
the write method of one argument on each of the bytes to be
written out. Subclasses are encouraged to override this method and
provide a more efficient implementation.
If b
is null
, a
NullPointerException
is thrown.
If off
is negative, or len
is negative, or
off+len
is greater than the length of the array
b
, then an IndexOutOfBoundsException is thrown.
write
in class OutputStream
b
- the data.off
- the start offset in the data.len
- the number of bytes to write.IOException
- if an I/O error occurs. In particular,
an IOException
is thrown if the output
stream is closed.public void close() throws IOException
java.io.OutputStream
close
is that it closes the output stream. A closed stream cannot perform
output operations and cannot be reopened.
The close
method of OutputStream
does nothing.
close
in interface Closeable
close
in interface AutoCloseable
close
in class OutputStream
IOException
- if an I/O error occurs.public void flush() throws IOException
java.io.OutputStream
flush
is
that calling it is an indication that, if any bytes previously
written have been buffered by the implementation of the output
stream, such bytes should immediately be written to their
intended destination.
If the intended destination of this stream is an abstraction provided by the underlying operating system, for example a file, then flushing the stream guarantees only that bytes previously written to the stream are passed to the operating system for writing; it does not guarantee that they are actually written to a physical device such as a disk drive.
The flush
method of OutputStream
does nothing.
flush
in interface Flushable
flush
in class OutputStream
IOException
- if an I/O error occurs.Copyright © 2010–2019. All rights reserved.