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jRandomAccessFile

List of types:

AsyncStreams
B4XSerializator
CompressedStreams
CountingInputStream
CountingOutputStream
RandomAccessFile

AsyncStreams

The AsyncStreams object allows you to read from an InputStream and write to an OutputStream in the background without blocking the main thread.
See the AsyncStreams Tutorial.
NewData event is raised when new data is available.
Error event is raised when an error was encountered. You should check LastException to find the error.
Terminated event is raised when the other side has terminated the connection.
NewStream event is only raised in prefix mode when the other side sends a stream with WriteStream. This event is raised after the complete stream was received successfully.
The event includes the saved stream folder and name. Note that the file name is an arbitrary string.

Events:

NewData (Buffer() As Byte)
Error
Terminated
NewStream (Dir As String, FileName As String)

Members:

Close

Initialize (In As java.io.InputStream, Out As java.io.OutputStream, EventName As String)

InitializePrefix (In As java.io.InputStream, BigEndian As Boolean, Out As java.io.OutputStream, EventName As String)

IsInitialized As Boolean

OutputQueueSize As Int [read only]

SendAllAndClose As Boolean

StreamFolder As String

StreamReceived As Long [read only]

StreamTotal As Long [read only]

Write (Buffer() As Byte) As Boolean

Write2 (Buffer() As Byte, Start As Int, Length As Int) As Boolean

WriteStream (In As java.io.InputStream, Size As Long) As Boolean

Members description:

Close

Closes the associated streams.

Initialize (In As java.io.InputStream, Out As java.io.OutputStream, EventName As String)

Initializes the object. Unlike in prefix mode, the NewData event will be raised with new data as soon as it is available.
In - The InputStream that will be read. Pass Null if you only want to write with this object.
Out - The OutputStream that is used for writing the data. Pass Null if you only want to read with this object.
EventName - Determines the Subs that handle the NewData and Error events.

InitializePrefix (In As java.io.InputStream, BigEndian As Boolean, Out As java.io.OutputStream, EventName As String)

Initializes the object and sets it in "prefix" mode. In this mode incoming data should adhere to the following protocol:
Every message begins with the message length as an Int value (4 bytes). This length should not include the additional 4 bytes.
The NewData event will be raised only with full messages (not including the 4 bytes length value).
The prefix Int value will be added to the output messages automatically.
This makes it easier as you do not need to deal with broken messages.
In - The InputStream that will be read. Pass Null if you only want to write with this object.
BigEndian - Whether the length value is encoded in BigEndian or LittleEndian.
Out - The OutputStream that is used for writing the data. Pass Null if you only want to read with this object.
EventName - Determines the Subs that handle the NewData and Error events.

Write2 (Buffer() As Byte, Start As Int, Length As Int) As Boolean

WriteStream (In As java.io.InputStream, Size As Long) As Boolean

Writes the given stream. This method is only supported in prefix mode.
The checksum will be calculated and sent to the other size. The NewStream event will be raised, in the receiving side, after the stream was received successfully.
This method is more efficient than sending the same data in chunks. It can handle streams of any size.
In - InputStream that will be read. Note that the InputStream will be closed after the stream is sent.
Size - Number of bytes to read from the stream.

B4XSerializator

Events:

ObjectToBytes (Success As Boolean, Bytes() As Byte)
BytesToObject (Success As Boolean, NewObject As Object)

Members:

ConvertBytesToObject (Bytes() As Byte) As Object

ConvertBytesToObjectAsync (Bytes() As Byte, EventName As String)

ConvertObjectToBytes (Object As Object) As Byte()

ConvertObjectToBytesAsync (Object As Object, EventName As String)

Tag As Object

Members description:

ConvertBytesToObject (Bytes() As Byte) As Object

In-memory version of RandomAccessFile.ReadB4XObject.

ConvertBytesToObjectAsync (Bytes() As Byte, EventName As String)

Asynchronously converts the bytes to object. The BytesToObject event will be raised when the object is ready.
Do not reuse the same B4XSerializator instance when calling asynchronous methods.

ConvertObjectToBytes (Object As Object) As Byte()

In-memory version of RandomAccessFile.WriteB4XObject.
The following types are supported: Lists, Arrays of bytes and Arrays of objects, Maps, Strings, primitive types and user defined types.
Note that user defined types should be declared in the Main module.

ConvertObjectToBytesAsync (Object As Object, EventName As String)

Asynchronously converts the object to bytes. The ObjectToBytes event will be raised with the serialized bytes.
Do not reuse the same B4XSerializator instance when calling asynchronous methods.

Tag As Object

Gets or sets the Tag value. This is a place holder that can used to store additional data.

CompressedStreams

CompressedStreams object allows you to compress and decompress data using gzip or zlib compression methods.
There are two options for working with CompressedStreams:
Wrapping another stream by calling WrapInputStream or WrapOutputStream.
Compressing or decompressing the data in memory.
The following example demonstrates the usage of this object:
Sub Globals

End Sub

Sub Activity_Create(FirstTime As Boolean)
  Dim sb As StringBuilder
  sb.Initialize
  'Concatenation operations are much faster with StringBuilder than with String.
  For i = 1 To 10000
    sb.Append("Playing with compressed streams.").Append(CRLF)
  Next
  Dim out As OutputStream
  Dim s As String
  Dim compress As CompressedStreams
  s = sb.ToString
  'Write the string without compressing it (we could have used File.WriteString instead).
  out = File.OpenOutput(File.DirTemp, "test.txt", False)
  WriteStringToStream(out, s)

  'Write the string with gzip compression.
  out = File.OpenOutput(File.DirTemp, "test.gz", False)
  out = compress.WrapOutputStream(out, "gzip")
  WriteStringToStream(out, s)

  'Write the string with zlib compression
  out = File.OpenOutput(File.DirTemp, "test.zlib", False)
  out = compress.WrapOutputStream(out, "zlib")
  WriteStringToStream(out, s)

  'Show the files sizes
  Msgbox("No compression: " & File.Size(File.DirTemp, "test.txt") & CRLF _
    & "Gzip: " & File.Size(File.DirTemp, "test.gz") & CRLF _
    & "zlib: " & File.Size(File.DirTemp, "test.zlib"), "Files sizes")

  'Read data from a compressed file
  Dim in As InputStream
  in = File.OpenInput(File.DirTemp, "test.zlib")
  in = compress.WrapInputStream(in, "zlib")
  Dim reader As TextReader
  reader.Initialize(in)
  Dim line As String
  line = reader.ReadLine
  Msgbox(line, "First line")
  reader.Close

  'In memory compression / decompression
  Dim data() As Byte
  data = "Playing with in-memory compression.".GetBytes("UTF8")
  Dim compressed(), decompressed() As Byte
  compressed = compress.CompressBytes(data, "gzip")
  decompressed = compress.DecompressBytes(compressed, "gzip")
  'In this case the compressed data is longer than the decompressed data.
  'The data is too short for the compression to be useful.
  Log("Compressed: " & compressed.Length)
  Log("Decompressed: " & decompressed.Length)
  Msgbox(BytesToString(decompressed,0, decompressed.Length, "UTF8"), "")
End Sub
Sub WriteStringToStream(Out As OutputStream, s As String)
  Dim t As TextWriter
  t.Initialize(Out)
  t.Write(s)
  t.Close 'Closes the internal stream as well
End Sub

Events:

None

Members:

CompressBytes (Data() As Byte, CompressMethod As String) As Byte()

DecompressBytes (CompressedData() As Byte, CompressMethod As String) As Byte()

WrapInputStream (In As java.io.InputStream, CompressMethod As String) As InputStreamWrapper

WrapOutputStream (Out As java.io.OutputStream, CompressMethod As String) As OutputStreamWrapper

Members description:

CompressBytes (Data() As Byte, CompressMethod As String) As Byte()

Returns a byte array with the compressed data.
Data - Data to compress.
CompressMethod - The name of the compression method (gzip or zlib).

DecompressBytes (CompressedData() As Byte, CompressMethod As String) As Byte()

Returns a byte array with the decompressed data.
CompressedData - The compressed data that should be decompressed.
CompressMethod - The name of the compression method (gzip or zlib).

WrapInputStream (In As java.io.InputStream, CompressMethod As String) As InputStreamWrapper

Wraps an input stream and returns an input stream that automatically decompresses the stream when it is read.
In - The original input stream.
CompressMethod - The name of the compression method (gzip or zlib).

WrapOutputStream (Out As java.io.OutputStream, CompressMethod As String) As OutputStreamWrapper

Wraps an output streams and returns an output stream that automatically compresses the data when it is written to the stream.
Out - The original output stream.
CompressMethod - The name of the compression method (gzip or zlib).

CountingInputStream

CountingInputStream and CountingOutputStream allow you to monitor the reading or writing progress.
Counting streams wrap the actual stream and provide a Count property which allows you to get the number of bytes read or written.
Counting streams are useful when the reading or writing operations are done in the background. You can then use a timer to monitor the progress.
This example logs the downloading progress:

Sub Process_Globals
  Dim hc As HttpClient
  Dim cout As CountingOutputStream
  Dim length As Int
  Dim timer1 As Timer
End Sub
Sub Globals

End Sub
Sub Activity_Create(FirstTime As Boolean)
  If FirstTime Then
    hc.Initialize("hc")
    timer1.Initialize("Timer1", 500)
  End If
  Dim req As HttpRequest
  req.InitializeGet("http://www.basic4ppc.com/android/files/b4a-trial.zip")
  hc.Execute(req, 1)
End Sub

Sub hc_ResponseSuccess (Response As HttpResponse, TaskId As Int)
  cout.Initialize(File.OpenOutput(File.DirRootExternal, "1.zip", False))
  Timer1.Enabled = True
  length = Response.ContentLength
  Response.GetAsynchronously("response", cOut, True, TaskId)
End Sub

Sub hc_ResponseError (Response As HttpResponse, Reason As String, StatusCode As Int, TaskId As Int)
  Log("Error: " & Reason)
  If Response <> Null Then
    Log(Response.GetString("UTF8"))
    Response.Release
  End If
End Sub

Sub Response_StreamFinish (Success As Boolean, TaskId As Int)
  timer1.Enabled = False
  If Success Then
    Timer1_Tick 'Show the current counter status
    Log("Success!")
  Else
    Log("Error: " & LastException.Message)
  End If
End Sub

Sub Timer1_Tick
  Log(cout.Count & " out of " & length)
End Sub

Events:

None

Members:

BytesAvailable As Int

Close

Count As Long

Initialize (InputStream As java.io.InputStream)

IsInitialized As Boolean

ReadBytes (arg0() As Byte, arg1 As Int, arg2 As Int) As Int

Members description:

BytesAvailable As Int

Close

Count As Long

Gets or sets the number of bytes read.

Initialize (InputStream As java.io.InputStream)

Initializes the counting stream by wrapping the given input stream.

IsInitialized As Boolean

ReadBytes (arg0() As Byte, arg1 As Int, arg2 As Int) As Int

CountingOutputStream

See CountingInputStream for more information.

Events:

None

Members:

Close

Count As Long

Flush

Initialize (OutputStream As java.io.OutputStream)

IsInitialized As Boolean

ToBytesArray As Byte()

WriteBytes (arg0() As Byte, arg1 As Int, arg2 As Int)

Members description:

Close

Count As Long

Gets or sets the number of bytes written.

Flush

Initialize (OutputStream As java.io.OutputStream)

Initializes the counting stream by wrapping the given output stream.

IsInitialized As Boolean

ToBytesArray As Byte()

WriteBytes (arg0() As Byte, arg1 As Int, arg2 As Int)

RandomAccessFile

This object allows you to non-sequentially access files and bytes arrays.
You can also use it to encode numbers to bytes (and vice versa).
Note that assets files (files added with the file manager) cannot be opened with this object as those files are actually packed inside the APK file.
A short tutorial about the encryption methods is available here.