Class FileBuffer
java.lang.Object
org.simpleframework.common.buffer.FileBuffer
- All Implemented Interfaces:
Buffer
The
FileBuffer
object is used to create a buffer
which will write the appended data to an underlying file. This
is typically used for buffers that are too large for to allocate
in memory. Data appended to the buffer can be retrieved at a
later stage by acquiring the InputStream
for the
underlying file. To ensure that excessive file system space is
not occupied the buffer files are cleaned every five minutes.- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate class
TheRange
object is used to provide a stream that can read a range of bytes from a provided input stream.private class
TheSegment
object is used to create a segment of the parent buffer. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate OutputStream
This is the file output stream used for this buffer object.private boolean
This is used to determine if this buffer has been closed.private long
This is the number of bytes currently appended to the buffer.private File
This is the path for the file that this buffer appends to.private FileBuffer.Segment
This represents the last file segment that has been created. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionallocate()
This is used to allocate a segment within this buffer.append
(byte[] array) This is used to append the specified data to the underlying file.append
(byte[] array, int off, int size) This is used to append the specified data to the underlying file.void
clear()
This will clear all data from the buffer.void
close()
This method is used to ensure the buffer can be closed.private String
convert
(InputStream source, String charset, int count) This method is used to acquire the buffered bytes as a string.encode()
This method is used to acquire the buffered bytes as a string.This method is used to acquire the buffered bytes as a string.long
length()
This is used to provide the number of bytes that have been written to the buffer.open()
This method is used so that a buffer can be represented as a stream of bytes.private InputStream
This method is used so that a buffer can be represented as a stream of bytes.
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Field Details
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buffer
This is the file output stream used for this buffer object. -
segment
This represents the last file segment that has been created. -
file
This is the path for the file that this buffer appends to. -
count
private long countThis is the number of bytes currently appended to the buffer. -
closed
private boolean closedThis is used to determine if this buffer has been closed.
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Constructor Details
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FileBuffer
Constructor for theFileBuffer
object. This will create a buffer using the provided file. All data appended to this buffer will effectively written to the underlying file. If the appended data needs to be retrieved at a later stage then it can be acquired using the buffers input stream.- Parameters:
file
- this is the file used for the file buffer- Throws:
IOException
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Method Details
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allocate
This is used to allocate a segment within this buffer. If the buffer is closed this will throw an exception, if however the buffer is still open then a segment is created which will write all appended data to this buffer. However it can be treated as an independent source of data.- Specified by:
allocate
in interfaceBuffer
- Returns:
- this returns a buffer which is a segment of this
- Throws:
IOException
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append
This is used to append the specified data to the underlying file. All bytes appended to the file can be consumed at a later stage by acquiring theInputStream
from this buffer. Also if require the data can be encoded as a string object in a required character set.- Specified by:
append
in interfaceBuffer
- Parameters:
array
- this is the array to write the the file- Returns:
- this returns this buffer for further operations
- Throws:
IOException
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append
This is used to append the specified data to the underlying file. All bytes appended to the file can be consumed at a later stage by acquiring theInputStream
from this buffer. Also if require the data can be encoded as a string object in a required character set.- Specified by:
append
in interfaceBuffer
- Parameters:
array
- this is the array to write the the fileoff
- this is the offset within the array to writesize
- this is the number of bytes to be appended- Returns:
- this returns this buffer for further operations
- Throws:
IOException
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encode
This method is used to acquire the buffered bytes as a string. This is useful if the contents need to be manipulated as a string or transferred into another encoding. If the UTF-8 content encoding is not supported the platform default is used, however this is unlikely as UTF-8 should be supported.- Specified by:
encode
in interfaceBuffer
- Returns:
- this returns a UTF-8 encoding of the buffer contents
- Throws:
IOException
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encode
This method is used to acquire the buffered bytes as a string. This is useful if the contents need to be manipulated as a string or transferred into another encoding. This will convert the bytes using the specified character encoding format.- Specified by:
encode
in interfaceBuffer
- Parameters:
charset
- this is the charset to encode the data with- Returns:
- this returns the encoding of the buffer contents
- Throws:
IOException
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convert
This method is used to acquire the buffered bytes as a string. This is useful if the contents need to be manipulated as a string or transferred into another encoding. This will convert the bytes using the specified character encoding format.- Parameters:
source
- this is the source stream that is to be encodedcharset
- this is the charset to encode the data withcount
- this is the number of bytes to be encoded- Returns:
- this returns the encoding of the buffer contents
- Throws:
IOException
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open
This method is used so that a buffer can be represented as a stream of bytes. This provides a quick means to access the data that has been written to the buffer. It wraps the buffer within an input stream so that it can be read directly.- Specified by:
open
in interfaceBuffer
- Returns:
- a stream that can be used to read the buffered bytes
- Throws:
IOException
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open
This method is used so that a buffer can be represented as a stream of bytes. This provides a quick means to access the data that has been written to the buffer. It wraps the buffer within an input stream so that it can be read directly.- Parameters:
file
- this is the file used to create the input stream- Returns:
- a stream that can be used to read the buffered bytes
- Throws:
IOException
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clear
This will clear all data from the buffer. This simply sets the count to be zero, it will not clear the memory occupied by the instance as the internal buffer will remain. This allows the memory occupied to be reused as many times as is required.- Specified by:
clear
in interfaceBuffer
- Throws:
IOException
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close
This method is used to ensure the buffer can be closed. Once the buffer is closed it is an immutable collection of bytes and can not longer be modified. This ensures that it can be passed by value without the risk of modification of the bytes.- Specified by:
close
in interfaceBuffer
- Throws:
IOException
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length
public long length()This is used to provide the number of bytes that have been written to the buffer. This increases as bytes are appended to the buffer. if the buffer is cleared this resets to zero.
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