de.uni_hildesheim.sse.monitoring.runtime.wrap

Class DelegatingRandomAccessFile

java.lang.Object

java.io.RandomAccessFile

de.uni_hildesheim.sse.monitoring.runtime.wrap.DelegatingRandomAccessFile

All Implemented Interfaces:

java.io.Closeable, java.io.DataInput, java.io.DataOutput, java.lang.AutoCloseable

public class DelegatingRandomAccessFile
extends java.io.RandomAccessFile

Instances of this class support both reading and writing to a random access file. A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the file pointer; input operations read bytes starting at the file pointer and advance the file pointer past the bytes read. If the random access file is created in read/write mode, then output operations are also available; output operations write bytes starting at the file pointer and advance the file pointer past the bytes written. Output operations that write past the current end of the implied array cause the array to be extended. The file pointer can be read by the getFilePointer method and set by the seek method.

We need this delegating class, because due to public native methods instrumentation does not work.

Since:

1.0

Author:

Holger Eichelberger

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	recId Stores the (optional) recording id.

Constructor Summary

Constructors

Constructor and Description
DelegatingRandomAccessFile(java.io.File file, java.lang.String mode) Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.
DelegatingRandomAccessFile(java.io.File file, java.lang.String mode, java.lang.String recId) Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.
DelegatingRandomAccessFile(java.lang.String name, java.lang.String mode) Creates a random access file stream to read from, and optionally to write to, a file with the specified name.
DelegatingRandomAccessFile(java.lang.String name, java.lang.String mode, java.lang.String recId) Creates a random access file stream to read from, and optionally to write to, a file with the specified name.

Method Summary

Modifier and Type	Method and Description
int	read() Reads a byte of data from this file.
int	read(byte[] buffer) Reads up to buffer.length bytes of data from this file into an array of bytes.
int	read(byte[] buffer, int off, int len) Reads up to len bytes of data from this file into an array of bytes.
void	write(byte[] buffer) Writes buffer.length bytes from the specified byte array to this file, starting at the current file pointer.
void	write(byte[] buffer, int off, int len) Writes len bytes from the specified byte array starting at offset off to this file.
void	write(int value) Writes the specified byte to this file.

Methods inherited from class java.io.RandomAccessFile

close, getChannel, getFD, getFilePointer, length, readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, seek, setLength, skipBytes, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

recId

private java.lang.String recId

Stores the (optional) recording id.

Constructor Detail

DelegatingRandomAccessFile

public DelegatingRandomAccessFile(java.lang.String name,
                                  java.lang.String mode)
                           throws java.io.FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, a file with the specified name. A new FileDescriptor object is created to represent the connection to the file.

Parameters:

name - the system-dependent filename

mode - the access mode

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd"

java.io.FileNotFoundException - if the mode is "r" but the given string does not denote an existing regular file, or if the mode begins with "rw" but the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

DelegatingRandomAccessFile

public DelegatingRandomAccessFile(java.io.File file,
                                  java.lang.String mode)
                           throws java.io.FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument. A new FileDescriptor object is created to represent this file connection.

Parameters:

file - the file object

mode - the access mode

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd"

java.io.FileNotFoundException - if the mode is "r" but the given file object does not denote an existing regular file, or if the mode begins with "rw" but the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

DelegatingRandomAccessFile

public DelegatingRandomAccessFile(java.lang.String name,
                                  java.lang.String mode,
                                  java.lang.String recId)
                           throws java.io.FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, a file with the specified name. A new FileDescriptor object is created to represent the connection to the file.

Parameters:

name - the system-dependent filename

mode - the access mode

recId - an optional recorder id

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd"

java.io.FileNotFoundException - if the mode is "r" but the given string does not denote an existing regular file, or if the mode begins with "rw" but the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

DelegatingRandomAccessFile

public DelegatingRandomAccessFile(java.io.File file,
                                  java.lang.String mode,
                                  java.lang.String recId)
                           throws java.io.FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument. A new FileDescriptor object is created to represent this file connection.

Parameters:

file - the file object

mode - the access mode

recId - an optional recorder id

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd"

java.io.FileNotFoundException - if the mode is "r" but the given file object does not denote an existing regular file, or if the mode begins with "rw" but the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

Method Detail

read

public int read()
         throws java.io.IOException

Reads a byte of data from this file. The byte is returned as an integer in the range 0 to 255 (0x00-0x0ff). This method blocks if no input is yet available.

Overrides:

read in class java.io.RandomAccessFile

Returns:

the next byte of data, or -1 if the end of the file has been reached.

Throws:

java.io.IOException - if an I/O error occurs. Not thrown if end-of-file has been reached.

read

public int read(byte[] buffer,
                int off,
                int len)
         throws java.io.IOException

Reads up to len bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Overrides:

read in class java.io.RandomAccessFile

Parameters:

buffer - the buffer into which the data is read.

off - the start offset in array buffer at which the data is written.

len - 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:

java.io.IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs.

java.lang.NullPointerException - If buffer is null.

java.lang.IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than buffer.length - off

read

public int read(byte[] buffer)
         throws java.io.IOException

Reads up to buffer.length bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Overrides:

read in class java.io.RandomAccessFile

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 file has been reached.

Throws:

java.io.IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs.

java.lang.NullPointerException - If buffer is null.

write

public void write(int value)
           throws java.io.IOException

Writes the specified byte to this file. The write starts at the current file pointer.

Specified by:

write in interface java.io.DataOutput

Overrides:

write in class java.io.RandomAccessFile

Parameters:

value - the byte to be written.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] buffer)
           throws java.io.IOException

Writes buffer.length bytes from the specified byte array to this file, starting at the current file pointer.

Specified by:

write in interface java.io.DataOutput

Overrides:

write in class java.io.RandomAccessFile

Parameters:

buffer - the data.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] buffer,
                  int off,
                  int len)
           throws java.io.IOException

Writes len bytes from the specified byte array starting at offset off to this file.

Specified by:

write in interface java.io.DataOutput

Overrides:

write in class java.io.RandomAccessFile

Parameters:

buffer - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

java.io.IOException - if an I/O error occurs.