XByteBuffer (Apache Tomcat 8.0.15 API Documentation)

java.lang.Object
- org.apache.catalina.tribes.io.XByteBuffer

```
public class XByteBuffer
extends Object
```
The XByteBuffer provides a dual functionality. One, it stores message bytes and automatically extends the byte buffer if needed.
Two, it can encode and decode packages so that they can be defined and identified as they come in on a socket.
THIS CLASS IS NOT THREAD SAFE

Transfer package:
- START_DATA- 7 bytes - FLT2002
- SIZE - 4 bytes - size of the data package
- DATA - should be as many bytes as the prev SIZE
- END_DATA - 7 bytes - TLF2003

Field Summary

Fields
Modifier and Type	Field and Description
`protected byte[]`	`buf` Variable to hold the data
`protected int`	`bufSize` Current length of data in the buffer
`protected boolean`	`discard` Flag for discarding invalid packages If this flag is set to true, and append(byte[],...) is called, the data added will be inspected, and if it doesn't start with `START_DATA` it will be thrown away.

Constructor Summary

Constructors
Constructor and Description
`XByteBuffer(byte[] data, boolean discard)`
`XByteBuffer(byte[] data, int size, boolean discard)`
`XByteBuffer(int size, boolean discard)` Constructs a new XByteBuffer.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`append(boolean i)`
`boolean`	`append(byte i)`
`boolean`	`append(byte[] b, int off, int len)`
`boolean`	`append(ByteBuffer b, int len)` Appends the data to the buffer.
`boolean`	`append(int i)`
`boolean`	`append(long i)`
`void`	`clear()` Resets the buffer
`int`	`countPackages()` Internal mechanism to make a check if a complete package exists within the buffer
`int`	`countPackages(boolean first)`
`static byte[]`	`createDataPackage(byte[] data)`
`static byte[]`	`createDataPackage(byte[] data, int doff, int dlength, byte[] buffer, int bufoff)`
`static byte[]`	`createDataPackage(ChannelData cdata)` Creates a complete data package
`static Serializable`	`deserialize(byte[] data)`
`static Serializable`	`deserialize(byte[] data, int offset, int length)`
`static Serializable`	`deserialize(byte[] data, int offset, int length, ClassLoader[] cls)`
`boolean`	`doesPackageExist()` Method to check if a package exists in this byte buffer.
`void`	`expand(int newcount)`
`XByteBuffer`	`extractDataPackage(boolean clearFromBuffer)` Extracts the message bytes from a package.
`ChannelData`	`extractPackage(boolean clearFromBuffer)`
`static int`	`firstIndexOf(byte[] src, int srcOff, byte[] find)` Similar to a String.IndexOf, but uses pure bytes
`byte[]`	`getBytes()` Returns the bytes in the buffer, in its exact length
`byte[]`	`getBytesDirect()`
`int`	`getCapacity()`
`static int`	`getDataPackageLength(int datalength)`
`boolean`	`getDiscard()`
`int`	`getLength()`
`void`	`reset()`
`static byte[]`	`serialize(Serializable msg)` Serializes a message into cluster data
`void`	`setDiscard(boolean discard)`
`void`	`setLength(int size)`
`static boolean`	`toBoolean(byte[] b, int offset)` Converts a byte array entry to boolean
`static byte[]`	`toBytes(boolean bool, byte[] data, int offset)` Converts a boolean to a 1-byte array
`static byte[]`	`toBytes(int n, byte[] b, int offset)` Converts an integer to four bytes
`static byte[]`	`toBytes(long n, byte[] b, int offset)` Converts an long to eight bytes
`static int`	`toInt(byte[] b, int off)` Convert four bytes to an int
`static long`	`toLong(byte[] b, int off)` Convert eight bytes to a long
`void`	`trim(int length)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - buf
```
protected byte[] buf
```
    Variable to hold the data
  - bufSize
```
protected int bufSize
```
    Current length of data in the buffer
  - discard
```
protected boolean discard
```
    Flag for discarding invalid packages If this flag is set to true, and append(byte[],...) is called, the data added will be inspected, and if it doesn't start with START_DATA it will be thrown away.
- Constructor Detail
  - XByteBuffer
```
public XByteBuffer(int size,
           boolean discard)
```
    Constructs a new XByteBuffer.
    TODO use a pool of byte[] for performance
    
    Parameters:
    size - - the initial size of the byte buffer
  - XByteBuffer
```
public XByteBuffer(byte[] data,
           boolean discard)
```
  - XByteBuffer
```
public XByteBuffer(byte[] data,
           int size,
           boolean discard)
```
- Method Detail
  - getLength
```
public int getLength()
```
  - setLength
```
public void setLength(int size)
```
  - trim
```
public void trim(int length)
```
  - reset
```
public void reset()
```
  - getBytesDirect
```
public byte[] getBytesDirect()
```
  - getBytes
```
public byte[] getBytes()
```
    Returns the bytes in the buffer, in its exact length
  - clear
```
public void clear()
```
    Resets the buffer
  - append
```
public boolean append(ByteBuffer b,
             int len)
```
    Appends the data to the buffer. If the data is incorrectly formatted, ie, the data should always start with the header, false will be returned and the data will be discarded.
    
    Parameters:
    b - - bytes to be appended
    len - - the number of bytes to append.
    
    Returns:
    true if the data was appended correctly. Returns false if the package is incorrect, ie missing header or something, or the length of data is 0
  - append
```
public boolean append(byte i)
```
  - append
```
public boolean append(boolean i)
```
  - append
```
public boolean append(long i)
```
  - append
```
public boolean append(int i)
```
  - append
```
public boolean append(byte[] b,
             int off,
             int len)
```
  - expand
```
public void expand(int newcount)
```
  - getCapacity
```
public int getCapacity()
```
  - countPackages
```
public int countPackages()
```
    Internal mechanism to make a check if a complete package exists within the buffer
    
    Returns:
    - true if a complete package (header,compress,size,data,footer) exists within the buffer
  - countPackages
```
public int countPackages(boolean first)
```
  - doesPackageExist
```
public boolean doesPackageExist()
```
    Method to check if a package exists in this byte buffer.
    
    Returns:
    - true if a complete package (header,options,size,data,footer) exists within the buffer
  - extractDataPackage
```
public XByteBuffer extractDataPackage(boolean clearFromBuffer)
```
    Extracts the message bytes from a package. If no package exists, a IllegalStateException will be thrown.
    
    Parameters:
    clearFromBuffer - - if true, the package will be removed from the byte buffer
    
    Returns:
    - returns the actual message bytes (header, compress,size and footer not included).
  - extractPackage
```
public ChannelData extractPackage(boolean clearFromBuffer)
```
  - createDataPackage
```
public static byte[] createDataPackage(ChannelData cdata)
```
    Creates a complete data package
    
    Parameters:
    cdata - - the message data to be contained within the package
    
    Returns:
    - a full package (header,size,data,footer)
  - createDataPackage
```
public static byte[] createDataPackage(byte[] data,
                       int doff,
                       int dlength,
                       byte[] buffer,
                       int bufoff)
```
  - getDataPackageLength
```
public static int getDataPackageLength(int datalength)
```
  - createDataPackage
```
public static byte[] createDataPackage(byte[] data)
```
  - toInt
```
public static int toInt(byte[] b,
        int off)
```
    Convert four bytes to an int
    
    Parameters:
    b - - the byte array containing the four bytes
    off - - the offset
    
    Returns:
    the integer value constructed from the four bytes
    
    Throws:
    
    ArrayIndexOutOfBoundsException
  - toLong
```
public static long toLong(byte[] b,
          int off)
```
    Convert eight bytes to a long
    
    Parameters:
    b - - the byte array containing the four bytes
    off - - the offset
    
    Returns:
    the long value constructed from the eight bytes
    
    Throws:
    
    ArrayIndexOutOfBoundsException
  - toBytes
```
public static byte[] toBytes(boolean bool,
             byte[] data,
             int offset)
```
    Converts a boolean to a 1-byte array
    
    Parameters:
    bool - - the integer
    
    Returns:
    - 1-byte array
  - toBoolean
```
public static boolean toBoolean(byte[] b,
                int offset)
```
    Converts a byte array entry to boolean
    
    Parameters:
    b - byte array
    offset - within byte array
    
    Returns:
    true if byte array entry is non-zero, false otherwise
  - toBytes
```
public static byte[] toBytes(int n,
             byte[] b,
             int offset)
```
    Converts an integer to four bytes
    
    Parameters:
    n - - the integer
    
    Returns:
    - four bytes in an array
  - toBytes
```
public static byte[] toBytes(long n,
             byte[] b,
             int offset)
```
    Converts an long to eight bytes
    
    Parameters:
    n - - the long
    
    Returns:
    - eight bytes in an array
  - firstIndexOf
```
public static int firstIndexOf(byte[] src,
               int srcOff,
               byte[] find)
```
    Similar to a String.IndexOf, but uses pure bytes
    
    Parameters:
    src - - the source bytes to be searched
    srcOff - - offset on the source buffer
    find - - the string to be found within src
    
    Returns:
    - the index of the first matching byte. -1 if the find array is not found
  - deserialize
```
public static Serializable deserialize(byte[] data)
                                throws IOException,
                                       ClassNotFoundException,
                                       ClassCastException
```
    Throws:
    
    IOException
    
    ClassNotFoundException
    
    ClassCastException
  - deserialize
```
public static Serializable deserialize(byte[] data,
                       int offset,
                       int length)
                                throws IOException,
                                       ClassNotFoundException,
                                       ClassCastException
```
    Throws:
    
    IOException
    
    ClassNotFoundException
    
    ClassCastException
  - deserialize
```
public static Serializable deserialize(byte[] data,
                       int offset,
                       int length,
                       ClassLoader[] cls)
                                throws IOException,
                                       ClassNotFoundException,
                                       ClassCastException
```
    Throws:
    
    IOException
    
    ClassNotFoundException
    
    ClassCastException
  - serialize
```
public static byte[] serialize(Serializable msg)
                        throws IOException
```
    Serializes a message into cluster data
    
    Parameters:
    msg - ClusterMessage
    
    Returns:
    serialized content as byte[] array
    
    Throws:
    
    IOException
  - setDiscard
```
public void setDiscard(boolean discard)
```
  - getDiscard
```
public boolean getDiscard()
```

Class XByteBuffer

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

buf

bufSize

discard

Constructor Detail

XByteBuffer

XByteBuffer

XByteBuffer

Method Detail

getLength

setLength

trim

reset

getBytesDirect

getBytes

clear

append

append

append

append

append

append

expand

getCapacity

countPackages

countPackages

doesPackageExist

extractDataPackage

extractPackage

createDataPackage

createDataPackage

getDataPackageLength

createDataPackage

toInt

toLong

toBytes

toBoolean

toBytes

toBytes

firstIndexOf

deserialize

deserialize

deserialize

serialize

setDiscard

getDiscard