de.uni_hildesheim.sse.monitoring.runtime.wrap.DelegatingRandomAccessFile Maven / Gradle / Ivy
package de.uni_hildesheim.sse.monitoring.runtime.wrap;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import de.uni_hildesheim.sse.monitoring.runtime.boot.RecorderFrontend;
import de.uni_hildesheim.sse.monitoring.runtime.boot.StreamType;
/**
* 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. Read still works with Java 9, write does not
* work and needs additional instrumentation.
*
* @author Holger Eichelberger
* @since 1.0
*/
public class DelegatingRandomAccessFile extends RandomAccessFile {
/**
* Stores the (optional) recording id.
*/
private String recId = null;
/**
* Creates a random access file stream to read from, and optionally
* to write to, a file with the specified name. A new
* {@link java.io.FileDescriptor} object is created to represent the
* connection to the file.
*
* @param name the system-dependent filename
* @param mode the access mode
* @exception IllegalArgumentException if the mode argument is not equal
* to one of "r", "rw", "rws", or
* "rwd"
* @exception 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
*/
public DelegatingRandomAccessFile(String name, String mode)
throws FileNotFoundException {
super(name, mode);
}
/**
* Creates a random access file stream to read from, and optionally to
* write to, the file specified by the {@link java.io.File} argument. A new
* {@link java.io.FileDescriptor} object is created to represent this file
* connection.
*
* @param file the file object
* @param mode the access mode
* @exception IllegalArgumentException if the mode argument is not equal
* to one of "r", "rw", "rws", or
* "rwd"
* @exception 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
*/
public DelegatingRandomAccessFile(File file, String mode)
throws FileNotFoundException {
super(file, mode);
}
/**
* Creates a random access file stream to read from, and optionally
* to write to, a file with the specified name. A new
* {@link java.io.FileDescriptor} object is created to represent the
* connection to the file.
*
* @param name the system-dependent filename
* @param mode the access mode
* @param recId an optional recorder id
* @exception IllegalArgumentException if the mode argument is not equal
* to one of "r", "rw", "rws", or
* "rwd"
* @exception 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
*/
public DelegatingRandomAccessFile(String name, String mode, String recId)
throws FileNotFoundException {
super(name, mode);
this.recId = recId;
}
/**
* Creates a random access file stream to read from, and optionally to
* write to, the file specified by the {@link File} argument. A new {@link
* java.io.FileDescriptor} object is created to represent this file
* connection.
*
* @param file the file object
* @param mode the access mode
* @param recId an optional recorder id
* @exception IllegalArgumentException if the mode argument is not equal
* to one of "r", "rw", "rws", or
* "rwd"
* @exception 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
*/
public DelegatingRandomAccessFile(File file, String mode, String recId)
throws FileNotFoundException {
super(file, mode);
this.recId = recId;
}
/**
* 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.
*
* @return the next byte of data, or -1 if the end of the
* file has been reached.
* @exception IOException if an I/O error occurs. Not thrown if
* end-of-file has been reached.
*/
public int read() throws IOException {
int result = super.read();
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.readIo(recId, null, 1, StreamType.FILE);
}
return result;
}
/**
* 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.
*
* @param buffer the buffer into which the data is read.
* @param off the start offset in array buffer
* at which the data is written.
* @param len the maximum number of bytes read.
* @return 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.
* @exception 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.
* @exception NullPointerException If buffer is
* null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* buffer.length - off
*/
public int read(byte[] buffer, int off, int len) throws IOException {
int result = super.read(buffer, off, len);
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.readIo(
recId, null, buffer.length, StreamType.FILE);
}
return result;
}
/**
* 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.
*
* @param buffer the buffer into which the data is read.
* @return 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.
* @exception 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.
* @exception NullPointerException If buffer is
* null.
*/
public int read(byte[] buffer) throws IOException {
int result = super.read(buffer);
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.readIo(
recId, null, buffer.length, StreamType.FILE);
}
return result;
}
/**
* Writes the specified byte to this file. The write starts at
* the current file pointer.
*
* @param value the byte to be written.
* @exception IOException if an I/O error occurs.
*/
public void write(int value) throws IOException {
super.write(value);
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.writeIo(recId, null, 1, StreamType.FILE);
}
}
/**
* Writes buffer.length bytes from the specified byte array
* to this file, starting at the current file pointer.
*
* @param buffer the data.
* @exception IOException if an I/O error occurs.
*/
public void write(byte[] buffer) throws IOException {
super.write(buffer);
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.writeIo(
recId, null, buffer.length, StreamType.FILE);
}
}
/**
* Writes len bytes from the specified byte array
* starting at offset off to this file.
*
* @param buffer the data.
* @param off the start offset in the data.
* @param len the number of bytes to write.
* @exception IOException if an I/O error occurs.
*/
public void write(byte[] buffer, int off, int len) throws IOException {
super.write(buffer, off, len);
if (null != RecorderFrontend.instance) {
RecorderFrontend.instance.writeIo(
recId, null, buffer.length, StreamType.FILE);
}
}
}