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java.lang.Objectucar.unidata.io.RandomAccessFile
@NotThreadSafe public class RandomAccessFile
A buffered drop-in replacement for java.io.RandomAccessFile. Instances of this class realise substantial speed increases over java.io.RandomAccessFile through the use of buffering. This is a subclass of Object, as it was not possible to subclass java.io.RandomAccessFile because many of the methods are final. However, if it is necessary to use RandomAccessFile and java.io.RandomAccessFile interchangeably, both classes implement the DataInput and DataOutput interfaces.
By Russ Rew, based on BufferedRandomAccessFile by Alex McManus, based on Sun's source code for java.io.RandomAccessFile. For Alex McManus version from which this derives, see his Freeware Java Classes.
DataInput
,
DataOutput
,
RandomAccessFile
Field Summary | |
---|---|
static int |
BIG_ENDIAN
|
static int |
LITTLE_ENDIAN
|
Constructor Summary | |
---|---|
RandomAccessFile(java.lang.String location,
java.lang.String mode)
Constructor, default buffer size. |
|
RandomAccessFile(java.lang.String location,
java.lang.String mode,
int bufferSize)
Constructor. |
Method Summary | |
---|---|
void |
close()
Close the file, and release any associated system resources. |
void |
flush()
Copy the contents of the buffer to the disk. |
int |
getBufferSize()
Get the buffer size |
static boolean |
getDebugLeaks()
Debugging, do not use. |
java.io.FileDescriptor |
getFD()
Returns the opaque file descriptor object associated with this file. |
long |
getFilePointer()
Returns the current position in the file, where the next read or write will occur. |
java.lang.String |
getLocation()
Get the file location, or name. |
static java.util.List<java.lang.String> |
getOpenFiles()
Debugging, do not use. |
java.io.RandomAccessFile |
getRandomAccessFile()
Allow access to the underlying java.io.RandomAccessFile. |
boolean |
isAtEndOfFile()
Return true if file pointer is at end of file. |
long |
length()
Get the length of the file. |
void |
order(int endian)
Change the current endian mode. |
int |
read()
Read a byte of data from the file, blocking until data is available. |
int |
read(byte[] b)
Read up to b.length( ) bytes into an array. |
int |
read(byte[] b,
int off,
int len)
Read up to len bytes into an array, at a specified
offset. |
boolean |
readBoolean()
Reads a boolean from this file. |
byte |
readByte()
Reads a signed 8-bit value from this file. |
byte[] |
readBytes(int count)
Read fully count number of bytes |
char |
readChar()
Reads a Unicode character from this file. |
double |
readDouble()
Reads a double from this file. |
void |
readDouble(double[] pa,
int start,
int n)
Read an array of doubles |
float |
readFloat()
Reads a float from this file. |
void |
readFloat(float[] pa,
int start,
int n)
Read an array of floats |
void |
readFully(byte[] b)
Reads b.length bytes from this file into the byte
array. |
void |
readFully(byte[] b,
int off,
int len)
Reads exactly len bytes from this file into the byte
array. |
int |
readInt()
Reads a signed 32-bit integer from this file. |
void |
readInt(int[] pa,
int start,
int n)
Read an array of ints |
int |
readIntUnbuffered(long pos)
Read an integer at the given position, bypassing all buffering. |
java.lang.String |
readLine()
Reads the next line of text from this file. |
long |
readLong()
Reads a signed 64-bit integer from this file. |
void |
readLong(long[] pa,
int start,
int n)
Read an array of longs |
short |
readShort()
Reads a signed 16-bit number from this file. |
void |
readShort(short[] pa,
int start,
int n)
Read an array of shorts |
java.lang.String |
readString(int nbytes)
Read a String of knoen length. |
long |
readToByteChannel(java.nio.channels.WritableByteChannel dest,
long offset,
long nbytes)
Read nbytes bytes, at the specified file offset, send to a WritableByteChannel. |
int |
readUnsignedByte()
Reads an unsigned 8-bit number from this file. |
int |
readUnsignedShort()
Reads an unsigned 16-bit number from this file. |
java.lang.String |
readUTF()
Reads in a string from this file. |
boolean |
searchForward(KMPMatch match,
int maxBytes)
Search forward from the current pos, looking for a match. |
void |
seek(long pos)
Set the position in the file for the next read or write. |
void |
setBufferSize(int bufferSize)
Set the buffer size. |
static void |
setDebugAccess(boolean b)
Debugging, do not use. |
static void |
setDebugLeaks(boolean b)
Debugging, do not use. |
void |
setExtendMode()
Set extendMode for truncated, yet valid files - old NetCDF code allowed this when NOFILL on, and user doesnt write all variables. |
void |
setMinLength(long minLength)
Make sure file is at least this long when its closed. |
int |
skipBytes(int n)
Skips exactly n bytes of input. |
java.lang.String |
toString()
Create a string representation of this object. |
void |
unread()
Unread the last byte read. |
void |
write(byte[] b)
Writes b.length bytes from the specified byte array
starting at offset off to this file. |
void |
write(byte[] b,
int off,
int len)
Writes len bytes from the specified byte array
starting at offset off to this file. |
void |
write(int b)
Write a byte to the file. |
void |
writeBoolean(boolean v)
Writes a boolean to the file as a 1-byte value. |
void |
writeBoolean(boolean[] pa,
int start,
int n)
Write an array of booleans |
void |
writeByte(int v)
Writes a byte to the file as a 1-byte value. |
void |
writeBytes(byte[] b,
int off,
int len)
Write len bytes from an array to the file. |
void |
writeBytes(char[] b,
int off,
int len)
Writes the character array to the file as a sequence of bytes. |
void |
writeBytes(java.lang.String s)
Writes the string to the file as a sequence of bytes. |
void |
writeChar(char[] pa,
int start,
int n)
Write an array of chars |
void |
writeChar(int v)
Writes a char to the file as a 2-byte value, high
byte first. |
void |
writeChars(java.lang.String s)
Writes a string to the file as a sequence of characters. |
void |
writeDouble(double v)
Converts the double argument to a long using the
doubleToLongBits method in class Double ,
and then writes that long value to the file as an
8-byte quantity, high byte first. |
void |
writeDouble(double[] pa,
int start,
int n)
Write an array of doubles |
void |
writeFloat(float v)
Converts the float argument to an int using the
floatToIntBits method in class Float ,
and then writes that int value to the file as a
4-byte quantity, high byte first. |
void |
writeFloat(float[] pa,
int start,
int n)
Write an array of floats |
void |
writeInt(int v)
Writes an int to the file as four bytes, high byte first. |
void |
writeInt(int[] pa,
int start,
int n)
Write an array of ints |
void |
writeLong(long v)
Writes a long to the file as eight bytes, high byte first. |
void |
writeLong(long[] pa,
int start,
int n)
Write an array of longs |
void |
writeShort(int v)
Writes a short to the file as two bytes, high byte first. |
void |
writeShort(short[] pa,
int start,
int n)
Write an array of shorts |
void |
writeUTF(java.lang.String str)
Writes a string to the file using UTF-8 encoding in a machine-independent manner. |
Methods inherited from class java.lang.Object |
---|
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
---|
public static final int BIG_ENDIAN
public static final int LITTLE_ENDIAN
Constructor Detail |
---|
public RandomAccessFile(java.lang.String location, java.lang.String mode) throws java.io.IOException
location
- location of the filemode
- same as for java.io.RandomAccessFile
java.io.IOException
- on open errorpublic RandomAccessFile(java.lang.String location, java.lang.String mode, int bufferSize) throws java.io.IOException
location
- location of the filemode
- same as for java.io.RandomAccessFilebufferSize
- size of buffer to use.
java.io.IOException
- on open errorMethod Detail |
---|
public static boolean getDebugLeaks()
public static void setDebugLeaks(boolean b)
b
- set true to track java.io.RandomAccessFilepublic static void setDebugAccess(boolean b)
b
- to debug file readingpublic static java.util.List<java.lang.String> getOpenFiles()
public java.io.RandomAccessFile getRandomAccessFile()
public void setBufferSize(int bufferSize)
bufferSize
- length in bytespublic int getBufferSize()
public void close() throws java.io.IOException
java.io.IOException
- if an I/O error occurrs.public boolean isAtEndOfFile()
public void seek(long pos) throws java.io.IOException
pos
- the offset (in bytes) from the start of the file.
java.io.IOException
- if an I/O error occurrs.public long getFilePointer() throws java.io.IOException
java.io.IOException
- if an I/O error occurrs.public java.lang.String getLocation()
public long length() throws java.io.IOException
java.io.IOException
- if an I/O error occurrs.public void order(int endian)
endian
- RandomAccessFile.BIG_ENDIAN or RandomAccessFile.LITTLE_ENDIANpublic java.io.FileDescriptor getFD() throws java.io.IOException
java.io.IOException
- if an I/O error occurs.public void flush() throws java.io.IOException
java.io.IOException
- if an I/O error occurrs.public void setMinLength(long minLength)
minLength
- minimum length of the file.public void setExtendMode()
public int read() throws java.io.IOException
java.io.IOException
- if an I/O error occurrs.public long readToByteChannel(java.nio.channels.WritableByteChannel dest, long offset, long nbytes) throws java.io.IOException
nbytes
bytes, at the specified file offset, send to a WritableByteChannel.
This will block until all bytes are read.
This uses the underlying file channel directly, bypassing all user buffers.
dest
- write to this WritableByteChannel.offset
- the offset in the file where copying will start.nbytes
- the number of bytes to read.
java.io.IOException
- if an I/O error occurs.public int read(byte[] b, int off, int len) throws java.io.IOException
len
bytes into an array, at a specified
offset. This will block until at least one byte has been read.
b
- the byte array to receive the bytes.off
- the offset in the array where copying will start.len
- the number of bytes to copy.
java.io.IOException
- if an I/O error occurrs.public int read(byte[] b) throws java.io.IOException
b.length( )
bytes into an array. This
will block until at least one byte has been read.
b
- the byte array to receive the bytes.
java.io.IOException
- if an I/O error occurrs.public byte[] readBytes(int count) throws java.io.IOException
count
- how many bytes tp read
java.io.IOException
- if an I/O error occurrs.public final void readFully(byte[] b) throws java.io.IOException
b.length
bytes from this file into the byte
array. This method reads repeatedly from the file until all the
bytes are read. This method blocks until all the bytes are read,
the end of the stream is detected, or an exception is thrown.
readFully
in interface java.io.DataInput
b
- the buffer into which the data is read.
java.io.EOFException
- if this file reaches the end before reading
all the bytes.
java.io.IOException
- if an I/O error occurs.public final void readFully(byte[] b, int off, int len) throws java.io.IOException
len
bytes from this file into the byte
array. This method reads repeatedly from the file until all the
bytes are read. This method blocks until all the bytes are read,
the end of the stream is detected, or an exception is thrown.
readFully
in interface java.io.DataInput
b
- the buffer into which the data is read.off
- the start offset of the data.len
- the number of bytes to read.
java.io.EOFException
- if this file reaches the end before reading
all the bytes.
java.io.IOException
- if an I/O error occurs.public int skipBytes(int n) throws java.io.IOException
n
bytes of input.
This method blocks until all the bytes are skipped, the end of
the stream is detected, or an exception is thrown.
skipBytes
in interface java.io.DataInput
n
- the number of bytes to be skipped.
n
.
java.io.EOFException
- if this file reaches the end before skipping
all the bytes.
java.io.IOException
- if an I/O error occurs.public void unread()
public void write(int b) throws java.io.IOException
write
in interface java.io.DataOutput
b
- write this byte
java.io.IOException
- if an I/O error occurrs.public void writeBytes(byte[] b, int off, int len) throws java.io.IOException
len
bytes from an array to the file.
b
- the array containing the data.off
- the offset in the array to the data.len
- the length of the data.
java.io.IOException
- if an I/O error occurrs.public void write(byte[] b) throws java.io.IOException
b.length
bytes from the specified byte array
starting at offset off
to this file.
write
in interface java.io.DataOutput
b
- the data.
java.io.IOException
- if an I/O error occurs.public void write(byte[] b, int off, int len) throws java.io.IOException
len
bytes from the specified byte array
starting at offset off
to this file.
write
in interface java.io.DataOutput
b
- the data.off
- the start offset in the data.len
- the number of bytes to write.
java.io.IOException
- if an I/O error occurs.public final boolean readBoolean() throws java.io.IOException
boolean
from this file. This method reads a
single byte from the file. A value of 0
represents
false
. Any other value represents true
.
This method blocks until the byte is read, the end of the stream
is detected, or an exception is thrown.
readBoolean
in interface java.io.DataInput
boolean
value read.
java.io.EOFException
- if this file has reached the end.
java.io.IOException
- if an I/O error occurs.public final byte readByte() throws java.io.IOException
b
, where
0 <= b <= 255
,
then the result is:
(byte)(b)
readByte
in interface java.io.DataInput
byte
.
java.io.EOFException
- if this file has reached the end.
java.io.IOException
- if an I/O error occurs.public final int readUnsignedByte() throws java.io.IOException
readUnsignedByte
in interface java.io.DataInput
java.io.EOFException
- if this file has reached the end.
java.io.IOException
- if an I/O error occurs.public final short readShort() throws java.io.IOException
b1
and b2
, where each of the two values is
between 0
and 255
, inclusive, then the
result is equal to:
(short)((b1 << 8) | b2)
readShort
in interface java.io.DataInput
java.io.EOFException
- if this file reaches the end before reading
two bytes.
java.io.IOException
- if an I/O error occurs.public final void readShort(short[] pa, int start, int n) throws java.io.IOException
pa
- read into this arraystart
- starting at pa[start]n
- read this many elements
java.io.IOException
- on read errorpublic final int readUnsignedShort() throws java.io.IOException
b1
and b2
, where
0 <= b1, b2 <= 255
,
then the result is equal to:
(b1 << 8) | b2
readUnsignedShort
in interface java.io.DataInput
java.io.EOFException
- if this file reaches the end before reading
two bytes.
java.io.IOException
- if an I/O error occurs.public final char readChar() throws java.io.IOException
b1
and b2
, where
0 <= b1, b2 <= 255
,
then the result is equal to:
(char)((b1 << 8) | b2)
readChar
in interface java.io.DataInput
java.io.EOFException
- if this file reaches the end before reading
two bytes.
java.io.IOException
- if an I/O error occurs.public final int readInt() throws java.io.IOException
b1
,
b2
, b3
, and b4
, where
0 <= b1, b2, b3, b4 <= 255
,
then the result is equal to:
(b1 << 24) | (b2 << 16) + (b3 << 8) + b4
readInt
in interface java.io.DataInput
int
.
java.io.EOFException
- if this file reaches the end before reading
four bytes.
java.io.IOException
- if an I/O error occurs.public final int readIntUnbuffered(long pos) throws java.io.IOException
pos
- read a byte at this position
java.io.IOException
- if an I/O error occurs.public final void readInt(int[] pa, int start, int n) throws java.io.IOException
pa
- read into this arraystart
- starting at pa[start]n
- read this many elements
java.io.IOException
- on read errorpublic final long readLong() throws java.io.IOException
b1
, b2
, b3
,
b4
, b5
, b6
,
b7
, and b8,
where:
0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,
This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.((long)b1 << 56) + ((long)b2 << 48) + ((long)b3 << 40) + ((long)b4 << 32) + ((long)b5 << 24) + ((long)b6 << 16) + ((long)b7 << 8) + b8
readLong
in interface java.io.DataInput
long
.
java.io.EOFException
- if this file reaches the end before reading
eight bytes.
java.io.IOException
- if an I/O error occurs.public final void readLong(long[] pa, int start, int n) throws java.io.IOException
pa
- read into this arraystart
- starting at pa[start]n
- read this many elements
java.io.IOException
- on read errorpublic final float readFloat() throws java.io.IOException
float
from this file. This method reads an
int
value as if by the readInt
method
and then converts that int
to a float
using the intBitsToFloat
method in class
Float
.
This method blocks until the four bytes are read, the end of the
stream is detected, or an exception is thrown.
readFloat
in interface java.io.DataInput
float
.
java.io.EOFException
- if this file reaches the end before reading
four bytes.
java.io.IOException
- if an I/O error occurs.RandomAccessFile.readInt()
,
Float.intBitsToFloat(int)
public final void readFloat(float[] pa, int start, int n) throws java.io.IOException
pa
- read into this arraystart
- starting at pa[start]n
- read this many elements
java.io.IOException
- on read errorpublic final double readDouble() throws java.io.IOException
double
from this file. This method reads a
long
value as if by the readLong
method
and then converts that long
to a double
using the longBitsToDouble
method in
class Double
.
This method blocks until the eight bytes are read, the end of the
stream is detected, or an exception is thrown.
readDouble
in interface java.io.DataInput
double
.
java.io.EOFException
- if this file reaches the end before reading
eight bytes.
java.io.IOException
- if an I/O error occurs.RandomAccessFile.readLong()
,
Double.longBitsToDouble(long)
public final void readDouble(double[] pa, int start, int n) throws java.io.IOException
pa
- read into this arraystart
- starting at pa[start]n
- read this many elements
java.io.IOException
- on read errorpublic final java.lang.String readLine() throws java.io.IOException
'\r'
), a newline character ('\n'
), a
carriage-return character immediately followed by a newline
character, or the end of the input stream. The line-terminating
character(s), if any, are included as part of the string returned.
This method blocks until a newline character is read, a carriage
return and the byte following it are read (to see if it is a
newline), the end of the stream is detected, or an exception is thrown.
readLine
in interface java.io.DataInput
java.io.IOException
- if an I/O error occurs.public final java.lang.String readUTF() throws java.io.IOException
readUnsignedShort
. This value gives the number of
following bytes that are in the encoded string, not
the length of the resulting string. The following bytes are then
interpreted as bytes encoding characters in the UTF-8 format
and are converted into characters.
This method blocks until all the bytes are read, the end of the
stream is detected, or an exception is thrown.
readUTF
in interface java.io.DataInput
java.io.EOFException
- if this file reaches the end before
reading all the bytes.
java.io.IOException
- if an I/O error occurs.
java.io.UTFDataFormatException
- if the bytes do not represent
valid UTF-8 encoding of a Unicode string.RandomAccessFile.readUnsignedShort()
public java.lang.String readString(int nbytes) throws java.io.IOException
nbytes
- number of bytes to read
java.io.IOException
- if an I/O error occurs.public final void writeBoolean(boolean v) throws java.io.IOException
boolean
to the file as a 1-byte value. The
value true
is written out as the value
(byte)1
; the value false
is written out
as the value (byte)0
.
writeBoolean
in interface java.io.DataOutput
v
- a boolean
value to be written.
java.io.IOException
- if an I/O error occurs.public final void writeBoolean(boolean[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- write this number of elements
java.io.IOException
- on read errorpublic final void writeByte(int v) throws java.io.IOException
byte
to the file as a 1-byte value.
writeByte
in interface java.io.DataOutput
v
- a byte
value to be written.
java.io.IOException
- if an I/O error occurs.public final void writeShort(int v) throws java.io.IOException
short
to the file as two bytes, high byte first.
writeShort
in interface java.io.DataOutput
v
- a short
to be written.
java.io.IOException
- if an I/O error occurs.public final void writeShort(short[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- this number of elements
java.io.IOException
- on read errorpublic final void writeChar(int v) throws java.io.IOException
char
to the file as a 2-byte value, high
byte first.
writeChar
in interface java.io.DataOutput
v
- a char
value to be written.
java.io.IOException
- if an I/O error occurs.public final void writeChar(char[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- this number of elements
java.io.IOException
- on read errorpublic final void writeInt(int v) throws java.io.IOException
int
to the file as four bytes, high byte first.
writeInt
in interface java.io.DataOutput
v
- an int
to be written.
java.io.IOException
- if an I/O error occurs.public final void writeInt(int[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- write this number of elements
java.io.IOException
- on read errorpublic final void writeLong(long v) throws java.io.IOException
long
to the file as eight bytes, high byte first.
writeLong
in interface java.io.DataOutput
v
- a long
to be written.
java.io.IOException
- if an I/O error occurs.public final void writeLong(long[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- write this number of elements
java.io.IOException
- on read errorpublic final void writeFloat(float v) throws java.io.IOException
int
using the
floatToIntBits
method in class Float
,
and then writes that int
value to the file as a
4-byte quantity, high byte first.
writeFloat
in interface java.io.DataOutput
v
- a float
value to be written.
java.io.IOException
- if an I/O error occurs.Float.floatToIntBits(float)
public final void writeFloat(float[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- write this number of elements
java.io.IOException
- on read errorpublic final void writeDouble(double v) throws java.io.IOException
long
using the
doubleToLongBits
method in class Double
,
and then writes that long
value to the file as an
8-byte quantity, high byte first.
writeDouble
in interface java.io.DataOutput
v
- a double
value to be written.
java.io.IOException
- if an I/O error occurs.Double.doubleToLongBits(double)
public final void writeDouble(double[] pa, int start, int n) throws java.io.IOException
pa
- write from this arraystart
- starting with this element in the arrayn
- write this number of elements
java.io.IOException
- on read errorpublic final void writeBytes(java.lang.String s) throws java.io.IOException
writeBytes
in interface java.io.DataOutput
s
- a string of bytes to be written.
java.io.IOException
- if an I/O error occurs.public final void writeBytes(char[] b, int off, int len) throws java.io.IOException
b
- a character array of bytes to be written.off
- the index of the first character to write.len
- the number of characters to write.
java.io.IOException
- if an I/O error occurs.public final void writeChars(java.lang.String s) throws java.io.IOException
writeChar
method.
writeChars
in interface java.io.DataOutput
s
- a String
value to be written.
java.io.IOException
- if an I/O error occurs.RandomAccessFile.writeChar(int)
public final void writeUTF(java.lang.String str) throws java.io.IOException
writeShort
method giving the number of bytes to
follow. This value is the number of bytes actually written out,
not the length of the string. Following the length, each character
of the string is output, in sequence, using the UTF-8 encoding
for each character.
writeUTF
in interface java.io.DataOutput
str
- a string to be written.
java.io.IOException
- if an I/O error occurs.public java.lang.String toString()
toString
in class java.lang.Object
public boolean searchForward(KMPMatch match, int maxBytes) throws java.io.IOException
match
- the match youre looking for.maxBytes
- maximum number of bytes to search. use -1 for all
java.io.IOException
- on read error
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