XByteBuffer (Apache Tomcat 9.0.37 API Documentation)

org.apache.catalina.tribes.io

## Class XByteBuffer

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

- All Implemented Interfaces:
    Serializable

      public class XByteBuffer
      extends Object
      implements Serializable

  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
  See Also:
    Serialized Form

- - ### 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.
    `protected static StringManager` | `sm`

  - ### 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

    All Methods Static Methods Instance Methods Concrete 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()`
    `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 and put it in a 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 a 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

    - #### sm

          protected static final StringManager sm

    - #### 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
        `discard` - Flag for discarding invalid packages

    - #### 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

    - #### 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

    - #### toBytes

          public static byte[] toBytes(boolean bool,
                                       byte[] data,
                                       int offset)

      Converts a boolean and put it in a byte array.
      Parameters:
        `bool` - the integer
        `data` - the byte buffer in which the boolean will be placed
        `offset` - the offset in the byte array
      Returns:
        the 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
        `b` - the byte buffer in which the integer will be placed
        `offset` - the offset in the byte array
      Returns:
        four bytes in an array

    - #### toBytes

          public static byte[] toBytes(long n,
                                       byte[] b,
                                       int offset)

      Converts a long to eight bytes.
      Parameters:
        `n` - the long
        `b` - the byte buffer in which the integer will be placed
        `offset` - the offset in the byte array
      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` - Serialization error

    - #### setDiscard

          public void setDiscard(boolean discard)

    - #### getDiscard

          public boolean getDiscard()

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