RandomAccessFile

RandomAccessFile

RandomAccessFile(
    file: File!, 
    mode: String!)

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.

The mode argument specifies the access mode in which the file is to be opened. The permitted values and their meanings are:

The "rwd" mode can be used to reduce the number of I/O operations performed. Using "rwd" only requires updates to the file's content to be written to storage; using "rws" requires updates to both the file's content and its metadata to be written, which generally requires at least one more low-level I/O operation.

If there is a security manager, its checkRead method is called with the pathname of the file argument as its argument to see if read access to the file is allowed. If the mode allows writing, the security manager's checkWrite method is also called with the path argument to see if write access to the file is allowed.

RandomAccessFile

RandomAccessFile(
    name: String!, 
    mode: String!)

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.

The mode argument specifies the access mode with which the file is to be opened. The permitted values and their meanings are as specified for the RandomAccessFile(File,String) constructor.

If there is a security manager, its checkRead method is called with the name argument as its argument to see if read access to the file is allowed. If the mode allows writing, the security manager's checkWrite method is also called with the name argument as its argument to see if write access to the file is allowed.

close

open fun close(): Unit

Closes this random access file stream and releases any system resources associated with the stream. A closed random access file cannot perform input or output operations and cannot be reopened.

If this file has an associated channel then the channel is closed as well.

getChannel

fun getChannel(): FileChannel!

Returns the unique FileChannel object associated with this file.

The position of the returned channel will always be equal to this object's file-pointer offset as returned by the getFilePointer method. Changing this object's file-pointer offset, whether explicitly or by reading or writing bytes, will change the position of the channel, and vice versa. Changing the file's length via this object will change the length seen via the file channel, and vice versa.

getFD

fun getFD(): FileDescriptor!

Returns the opaque file descriptor object associated with this stream.

getFilePointer

open fun getFilePointer(): Long

Returns the current offset in this file.

length

open fun length(): Long

Returns the length of this file.

read

open fun read(): Int

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.

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read() method of InputStream.

read

open fun read(b: ByteArray!): Int

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

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[]) method of InputStream.

read

open fun read(
    b: ByteArray!, 
    off: Int, 
    len: Int
): Int

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.

Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[], int, int) method of InputStream.

readBoolean

fun readBoolean(): Boolean

Reads a boolean from this file. This method reads a single byte from the file, starting at the current file pointer. 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.

readByte

fun readByte(): Byte

Reads a signed eight-bit value from this file. This method reads a byte from the file, starting from the current file pointer. If the byte read is b, where 0 <= b <= 255, then the result is:

(byte)(b)
  

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

readChar

fun readChar(): Char

Reads a character from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

(char)((b1 << 8) | b2)
  

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

readDouble

fun readDouble(): Double

Reads a double from this file. This method reads a long value, starting at the current file pointer, 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.

readFloat

fun readFloat(): Float

Reads a float from this file. This method reads an int value, starting at the current file pointer, 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.

readFully

fun readFully(b: ByteArray!): Unit

Reads b.length bytes from this file into the byte array, starting at the current file pointer. This method reads repeatedly from the file until the requested number of bytes are read. This method blocks until the requested number of bytes are read, the end of the stream is detected, or an exception is thrown.

readFully

fun readFully(
    b: ByteArray!, 
    off: Int, 
    len: Int
): Unit

Reads exactly len bytes from this file into the byte array, starting at the current file pointer. This method reads repeatedly from the file until the requested number of bytes are read. This method blocks until the requested number of bytes are read, the end of the stream is detected, or an exception is thrown.

readInt

fun readInt(): Int

Reads a signed 32-bit integer from this file. This method reads 4 bytes from the file, starting at the current file pointer. If the bytes read, in order, are 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
  

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

readLine

fun readLine(): String!

Reads the next line of text from this file. This method successively reads bytes from the file, starting at the current file pointer, until it reaches a line terminator or the end of the file. Each byte is converted into a character by taking the byte's value for the lower eight bits of the character and setting the high eight bits of the character to zero. This method does not, therefore, support the full Unicode character set.

A line of text is terminated by a carriage-return character ('\u005Cr'), a newline character ('\u005Cn'), a carriage-return character immediately followed by a newline character, or the end of the file. Line-terminating characters are discarded and are not 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 file is reached, or an exception is thrown.

readLong

fun readLong(): Long

Reads a signed 64-bit integer from this file. This method reads eight bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1, b2, b3, b4, b5, b6, b7, and b8, where:

0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,
  

then the result is equal to:

((long)b1 << 56) + ((long)b2 << 48)
      + ((long)b3 << 40) + ((long)b4 << 32)
      + ((long)b5 << 24) + ((long)b6 << 16)
      + ((long)b7 << 8) + b8
  

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

readShort

fun readShort(): Short

Reads a signed 16-bit number from this file. The method reads two bytes from this file, starting at the current file pointer. If the two bytes read, in order, are 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)
  

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

readUTF

fun readUTF(): String!

Reads in a string from this file. The string has been encoded using a modified UTF-8 format.

The first two bytes are read, starting from the current file pointer, as if by 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 modified 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.

readUnsignedByte

fun readUnsignedByte(): Int

Reads an unsigned eight-bit number from this file. This method reads a byte from this file, starting at the current file pointer, and returns that byte.

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

readUnsignedShort

fun readUnsignedShort(): Int

Reads an unsigned 16-bit number from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:

(b1 << 8) | b2
  

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

seek

open fun seek(pos: Long): Unit

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

setLength

open fun setLength(newLength: Long): Unit

Sets the length of this file.

If the present length of the file as returned by the length method is greater than the newLength argument then the file will be truncated. In this case, if the file offset as returned by the getFilePointer method is greater than newLength then after this method returns the offset will be equal to newLength.

If the present length of the file as returned by the length method is smaller than the newLength argument then the file will be extended. In this case, the contents of the extended portion of the file are not defined.

skipBytes

open fun skipBytes(n: Int): Int

Attempts to skip over n bytes of input discarding the skipped bytes.

This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.

write

open fun write(b: ByteArray!): Unit

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

write

open fun write(
    b: ByteArray!, 
    off: Int, 
    len: Int
): Unit

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

write

open fun write(b: Int): Unit

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

writeBoolean

fun writeBoolean(v: Boolean): Unit

Writes a boolean to the file as a one-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0. The write starts at the current position of the file pointer.

writeByte

fun writeByte(v: Int): Unit

Writes a byte to the file as a one-byte value. The write starts at the current position of the file pointer.

writeBytes

fun writeBytes(s: String!): Unit

Writes the string to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits. The write starts at the current position of the file pointer.

writeChar

fun writeChar(v: Int): Unit

Writes a char to the file as a two-byte value, high byte first. The write starts at the current position of the file pointer.

writeChars

fun writeChars(s: String!): Unit

Writes a string to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method. The write starts at the current position of the file pointer.

writeDouble

fun writeDouble(v: Double): Unit

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 eight-byte quantity, high byte first. The write starts at the current position of the file pointer.

writeFloat

fun writeFloat(v: Float): Unit

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 four-byte quantity, high byte first. The write starts at the current position of the file pointer.

writeInt

fun writeInt(v: Int): Unit

Writes an int to the file as four bytes, high byte first. The write starts at the current position of the file pointer.

writeLong

fun writeLong(v: Long): Unit

Writes a long to the file as eight bytes, high byte first. The write starts at the current position of the file pointer.

writeShort

fun writeShort(v: Int): Unit

Writes a short to the file as two bytes, high byte first. The write starts at the current position of the file pointer.

writeUTF

fun writeUTF(str: String!): Unit

Writes a string to the file using modified UTF-8 encoding in a machine-independent manner.

First, two bytes are written to the file, starting at the current file pointer, as if by the 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 modified UTF-8 encoding for each character.

finalize

protected open fun finalize(): Unit