Package de.intarsys.tools.randomaccess
Interface IRandomAccess
- All Known Implementing Classes:
AbstractRandomAccess
,BufferedRandomAccess
,RandomAccessByteArray
,RandomAccessFile
,RandomAccessFilter
,RandomAccessViewport
public interface IRandomAccess
An interface for an object that can randomly access bytes in a data stream.
This is an abstraction of RandomAccessFile
to support other data
storage objects (like byte arrays and so on).
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Method Summary
Modifier and TypeMethodDescriptionAInputStream
view on the data structure.AOutputStream
view on the data structure.void
close()
Closes this random access data container and releases any system resources associated with the stream.void
flush()
Force changes to be made persistent.long
Returns the length of this data container.long
Returns the current offset in this data container.boolean
true
if this is a read only data container.void
mark()
Mark the current offset into the data in a stack like manner.int
read()
Reads a byte of data from this data container.int
read
(byte[] buffer) Reads up tobuffer.length
bytes of data from this data container into an array of bytes.int
read
(byte[] buffer, int start, int numBytes) Reads up tolen
bytes of data from this data container into an array of bytes.void
reset()
Reset to the last position on the mark-stack.void
seek
(long offset) Sets the offset, measured from the beginning of the data container at which the next read or write occurs.void
seekBy
(long delta) Sets the offset, measured from the current offset at which the next read or write occurs.void
setLength
(long newLength) Assign the length.void
write
(byte[] buffer) Writesb.length
bytes from the specified byte array, starting at the current offset.void
write
(byte[] buffer, int start, int numBytes) Writeslen
bytes from the specified byte array starting atstart
.void
write
(int b) Writes the specified byte .
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Method Details
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asInputStream
InputStream asInputStream()AInputStream
view on the data structure.- Returns:
- A
InputStream
view on the data structure.
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asOutputStream
OutputStream asOutputStream()AOutputStream
view on the data structure.- Returns:
- A
OutputStream
view on the data structure.
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close
Closes this random access data container and releases any system resources associated with the stream. A closed random access data container cannot perform input or output operations and cannot be reopened.- Throws:
IOException
- if an I/O error occurs.
-
flush
Force changes to be made persistent.- Throws:
IOException
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getLength
Returns the length of this data container.- Returns:
- the length of this data container, measured in bytes.
- Throws:
IOException
- if an I/O error occurs.
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getOffset
Returns the current offset in this data container.- Returns:
- the offset from the beginning of the data container, in bytes, at which the next read or write occurs.
- Throws:
IOException
- if an I/O error occurs.
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isReadOnly
boolean isReadOnly()true
if this is a read only data container.- Returns:
true
if this is a read only data container.
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mark
Mark the current offset into the data in a stack like manner.- Throws:
IOException
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read
Reads a byte of data from this data container. The byte is returned as an integer in the range 0 to 255 (0x00-0x0ff
). This method blocks if no input is yet available.This method behaves in exactly the same way as the
InputStream.read()
method ofInputStream
.- Returns:
- the next byte of data, or
-1
if the end of the data container has been reached. - Throws:
IOException
- if an I/O error occurs. Not thrown if the end of the data container has been reached.
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read
Reads up tobuffer.length
bytes of data from this data container into an array of bytes. This method blocks until at least one byte of input is available.This method behaves in the exactly the same way as the
InputStream.read(byte[])
method ofInputStream
.- Parameters:
buffer
- the buffer into which the data is read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of this data container has been reached. - Throws:
IOException
- if an I/O error occurs.
-
read
Reads up tolen
bytes of data from this data container into an array of bytes. This method blocks until at least one byte of input is available.- Parameters:
buffer
- the buffer into which the data is read.start
- the start offset of the data.numBytes
- the maximum number of bytes read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the file has been reached. - Throws:
IOException
- if an I/O error occurs.
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reset
Reset to the last position on the mark-stack.- Throws:
IOException
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seek
Sets the offset, measured from the beginning of the data container at which the next read or write occurs. The offset may be set beyond the end of the data container. Setting the offset beyond the end of the data container does not change the data container length. The length will change only by writing after the offset has been set beyond the end of the data container.- Parameters:
offset
- the offset position, measured in bytes from the beginning of the data container- Throws:
IOException
- ifoffset
is less than0
or if an I/O error occurs.
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seekBy
Sets the offset, measured from the current offset at which the next read or write occurs. The offset may be set beyond the end of the data container. Setting the offset beyond the end of the data container does not change the data container length. The length will change only by writing after the offset has been set beyond the end of the data container.- Parameters:
delta
- the amount of bytes by which to change the current offset position- Throws:
IOException
- if the resultingoffset
is less than0
or if an I/O error occurs.
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setLength
Assign the length. All bytes after length are truncated. If the real length is currently less than newLength, the data structure will be enlarged.- Parameters:
newLength
-- Throws:
IOException
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write
Writesb.length
bytes from the specified byte array, starting at the current offset.- Parameters:
buffer
- the data.- Throws:
IOException
- if an I/O error occurs.
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write
Writeslen
bytes from the specified byte array starting atstart
.- Parameters:
buffer
- the data.start
- the start offset in the data.numBytes
- the number of bytes to write.- Throws:
IOException
- if an I/O error occurs.
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write
Writes the specified byte . The write starts at the current offset.- Parameters:
b
- thebyte
to be written.- Throws:
IOException
- if an I/O error occurs.
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