javax.microedition.io
Interface RandomAccessConnection

All Superinterfaces:

Connection, DataInput, DataOutput, InputConnection, OutputConnection

All Known Subinterfaces:

DirectoryConnection

public interface RandomAccessConnection

extends InputConnection, OutputConnection, DataInput, DataOutput

A connection to a random access memory

Method Summary

long	getLength() Get the length of the data
long	getPosition() Returns the current offset into the data.
boolean	isSelected() Test to see if a record in the collection is selected.
int	read() Reads a byte of data.
int	read(byte[] b, int off, int len) Reads up to len bytes of data into an array of bytes.
void	seek(long pos) Sets the position pointer offset, measured from the beginning of the data, at which the next read or write occurs.
void	setLength(long len) Set the length of the data (for truncation).
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to the data
void	write(int b) Writes the specified byte to this file.

Methods inherited from interface javax.microedition.io.InputConnection

openDataInputStream, openInputStream

Methods inherited from interface javax.microedition.io.Connection

close

Methods inherited from interface javax.microedition.io.OutputConnection

openDataOutputStream, openOutputStream

Methods inherited from interface java.io.DataInput

readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, skipBytes

Methods inherited from interface java.io.DataOutput

write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Method Detail

isSelected

public boolean isSelected()
                   throws IOException

Test to see if a record in the collection is selected. Until this is done none of the data access methods below will work. Some random access connection are always selected, but other ones, such as a MetadataConncetion may require a specific record to be selected before I/O can commence.

Returns:

true if the connection is selected, otherwise false.

seek

public void seek(long pos)
          throws IOException

Sets the position pointer offset, measured from the beginning of the data, at which the next read or write occurs. The offset may be set beyond the end of the data. Setting the offset beyond the end of the data does not change the data length. The data length will change only by writing after the offset has been set beyond the end of the data.

Parameters:

pos - the offset position, measured in bytes from the beginning of the data, at which to set the position pointer.

Throws:

IOException - if pos is less than 0, if an I/O error occurs, or there is an input or output stream open on the data.

getPosition

public long getPosition()
                 throws IOException

Returns the current offset into the data.

Returns:

the offset from the beginning of the data, in bytes, at which the next read or write occurs.

Throws:

IOException - if an I/O error occurs.

getLength

public long getLength()
               throws IOException

Get the length of the data

Returns:

the length of the data

setLength

public void setLength(long len)
               throws IOException

Set the length of the data (for truncation).

Parameters:

len - the new length of the data

read

public int read()
         throws IOException

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

Returns:

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

Throws:

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

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

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

Parameters:

b - the buffer into which the data is read.

off - the start offset of the data.

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 data has been reached.

Throws:

IOException - if an I/O error occurs.

write

public void write(int b)
           throws IOException

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

Specified by:

write in interface DataOutput

Parameters:

b - the byte to be written.

Throws:

IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws IOException

Writes len bytes from the specified byte array starting at offset off to the data

Specified by:

write in interface DataOutput

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

IOException - if an I/O error occurs.