Package com.itextpdf.text.io
Class MappedChannelRandomAccessSource
- java.lang.Object
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- com.itextpdf.text.io.MappedChannelRandomAccessSource
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- All Implemented Interfaces:
RandomAccessSource
class MappedChannelRandomAccessSource extends java.lang.Object implements RandomAccessSource
A RandomAccessSource that represents a memory mapped section of an underlying FileChannel. This source can be closed and will automatically re-open as needed. This class is an internal implementation detail of theFileChannelRandomAccessSource
class and shouldn't be used by general iText users.- Since:
- 5.3.5
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Field Summary
Fields Modifier and Type Field Description private java.nio.channels.FileChannel
channel
The underlying channelprivate long
length
The number of bytes this source maps toprivate long
offset
The offset into the channel that this source maps toprivate ByteBufferRandomAccessSource
source
If the map is active, the actual map.
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Constructor Summary
Constructors Constructor Description MappedChannelRandomAccessSource(java.nio.channels.FileChannel channel, long offset, long length)
Create a new source based on the channel.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Closes this source.private static boolean
exceptionIsMapFailureException(java.io.IOException e)
Utility method that determines whether a given IOException is the result of a failure to map a memory mapped file.int
get(long position)
Gets a byte at the specified positionint
get(long position, byte[] bytes, int off, int len)
Gets an array at the specified position.long
length()
(package private) void
open()
Map the region of the channeljava.lang.String
toString()
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Field Detail
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channel
private final java.nio.channels.FileChannel channel
The underlying channel
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offset
private final long offset
The offset into the channel that this source maps to
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length
private final long length
The number of bytes this source maps to
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source
private ByteBufferRandomAccessSource source
If the map is active, the actual map. null other wise.
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Constructor Detail
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MappedChannelRandomAccessSource
public MappedChannelRandomAccessSource(java.nio.channels.FileChannel channel, long offset, long length)
Create a new source based on the channel. Mapping will not occur until data is actually read.- Parameters:
channel
- the underlying channeloffset
- the offset of the maplength
- the length of the map
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Method Detail
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open
void open() throws java.io.IOException
Map the region of the channel- Throws:
java.io.IOException
- if there is a problem with creating the map
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exceptionIsMapFailureException
private static boolean exceptionIsMapFailureException(java.io.IOException e)
Utility method that determines whether a given IOException is the result of a failure to map a memory mapped file. It would be better if the runtime provided a special exception for this case, but it doesn't, so we have to rely on parsing the exception message.- Parameters:
e
- the exception to check- Returns:
- true if the exception was the result of a failure to map a memory mapped file
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get
public int get(long position) throws java.io.IOException
Gets a byte at the specified position- Specified by:
get
in interfaceRandomAccessSource
- Returns:
- the byte, or -1 if EOF is reached
- Throws:
java.io.IOException
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get
public int get(long position, byte[] bytes, int off, int len) throws java.io.IOException
Gets an array at the specified position. If the number of bytes requested cannot be read, the bytes that can be read will be placed in bytes and the number actually read will be returned.- Specified by:
get
in interfaceRandomAccessSource
- Parameters:
position
- the position in the RandomAccessSource to read frombytes
- output bufferoff
- offset into the output buffer where results will be placedlen
- the number of bytes to read- Returns:
- the number of bytes actually read, or -1 if the file is at EOF
- Throws:
java.io.IOException
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length
public long length()
- Specified by:
length
in interfaceRandomAccessSource
- Returns:
- the length of this source
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close
public void close() throws java.io.IOException
Closes this source. The underlying data structure or source (if any) will also be closed- Specified by:
close
in interfaceRandomAccessSource
- Throws:
java.io.IOException
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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