org.apache.storm.utils

## Class WritableUtils

- java.lang.Object
- - org.apache.storm.utils.WritableUtils

-     public final class WritableUtils
      extends Object

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `WritableUtils()`

  - ### Method Summary

    All Methods Static Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static int` | `decodeVIntSize(byte value)` Parse the first byte of a vint/vlong to determine the number of bytes.
    `static void` | `displayByteArray(byte[] record)` Test Utility Method Display Byte Array.
    `static int` | `getVIntSize(long i)` Get the encoded length if an integer is stored in a variable-length format.
    `static boolean` | `isNegativeVInt(byte value)` Given the first byte of a vint/vlong, determine the sign.
    `static byte[]` | `readCompressedByteArray(DataInput in)`
    `static String` | `readCompressedString(DataInput in)` Ugly utility, maybe someone else can do this better.
    `static String[]` | `readCompressedStringArray(DataInput in)` Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
    `static String` | `readString(DataInput in)` Read a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF.
    `static String[]` | `readStringArray(DataInput in)` Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
    `static int` | `readVInt(DataInput stream)` Reads a zero-compressed encoded integer from input stream and returns it.
    `static long` | `readVLong(DataInput stream)` Reads a zero-compressed encoded long from input stream and returns it.
    `static void` | `skipCompressedByteArray(DataInput in)`
    `static void` | `skipFully(DataInput in, int len)` Skip len number of bytes in input streamin.
    `static int` | `writeCompressedByteArray(DataOutput out, byte[] bytes)`
    `static int` | `writeCompressedString(DataOutput out, String s)`
    `static void` | `writeCompressedStringArray(DataOutput out, String[] s)`
    `static void` | `writeString(DataOutput out, String s)` Write a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF.
    `static void` | `writeStringArray(DataOutput out, String[] s)` Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
    `static void` | `writeVInt(DataOutput stream, int i)` Serializes an integer to a binary stream with zero-compressed encoding.
    `static void` | `writeVLong(DataOutput stream, long i)` Serializes a long to a binary stream with zero-compressed encoding.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### WritableUtils

          public WritableUtils()

  - ### Method Detail

    - #### readCompressedByteArray

          public static byte[] readCompressedByteArray(DataInput in)
                                                throws IOException

      Throws:
        `IOException`

    - #### skipCompressedByteArray

          public static void skipCompressedByteArray(DataInput in)
                                              throws IOException

      Throws:
        `IOException`

    - #### writeCompressedByteArray

          public static int writeCompressedByteArray(DataOutput out,
                                                     byte[] bytes)
                                              throws IOException

      Throws:
        `IOException`

    - #### readCompressedString

          public static String readCompressedString(DataInput in)
                                             throws IOException

      Ugly utility, maybe someone else can do this better.

      Throws:
        `IOException`

    - #### writeCompressedString

          public static int writeCompressedString(DataOutput out,
                                                  String s)
                                           throws IOException

      Throws:
        `IOException`

    - #### writeString

          public static void writeString(DataOutput out,
                                         String s)
                                  throws IOException

      Write a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF. Encoding standard is… ?

      Throws:
        `IOException`

    - #### readString

          public static String readString(DataInput in)
                                   throws IOException

      Read a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF. Encoding standard is… ?

      Throws:
        `IOException`

    - #### writeStringArray

          public static void writeStringArray(DataOutput out,
                                              String[] s)
                                       throws IOException

      Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection.

      Throws:
        `IOException`

    - #### writeCompressedStringArray

          public static void writeCompressedStringArray(DataOutput out,
                                                        String[] s)
                                                 throws IOException

      Throws:
        `IOException`

    - #### readStringArray

          public static String[] readStringArray(DataInput in)
                                          throws IOException

      Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection. Actually this bit couldn’t…

      Throws:
        `IOException`

    - #### readCompressedStringArray

          public static String[] readCompressedStringArray(DataInput in)
                                                    throws IOException

      Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection. Handles null arrays and null values.

      Throws:
        `IOException`

    - #### displayByteArray

          public static void displayByteArray(byte[] record)

      Test Utility Method Display Byte Array.

    - #### writeVInt

          public static void writeVInt(DataOutput stream,
                                       int i)
                                throws IOException

      Serializes an integer to a binary stream with zero-compressed encoding. For -120 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the integer is positive or negative, and the number of bytes that follow. If the first byte value v is between -121 and -124, the following integer is positive, with number of bytes that follow are -(v+120). If the first byte value v is between -125 and -128, the following integer is negative, with number of bytes that follow are -(v+124). Bytes are stored in the high-non-zero-byte-first order.

      Parameters:
        `stream` - Binary output stream
        `i` - Integer to be serialized
      Throws:
        `IOException`

    - #### writeVLong

          public static void writeVLong(DataOutput stream,
                                        long i)
                                 throws IOException

      Serializes a long to a binary stream with zero-compressed encoding. For -112 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the long is positive or negative, and the number of bytes that follow. If the first byte value v is between -113 and -120, the following long is positive, with number of bytes that follow are -(v+112). If the first byte value v is between -121 and -128, the following long is negative, with number of bytes that follow are -(v+120). Bytes are stored in the high-non-zero-byte-first order.

      Parameters:
        `stream` - Binary output stream
        `i` - Long to be serialized
      Throws:
        `IOException`

    - #### readVLong

          public static long readVLong(DataInput stream)
                                throws IOException

      Reads a zero-compressed encoded long from input stream and returns it.

      Parameters:
        `stream` - Binary input stream
      Returns:
        deserialized long from stream.
      Throws:
        `IOException`

    - #### readVInt

          public static int readVInt(DataInput stream)
                              throws IOException

      Reads a zero-compressed encoded integer from input stream and returns it.

      Parameters:
        `stream` - Binary input stream
      Returns:
        deserialized integer from stream.
      Throws:
        `IOException`

    - #### isNegativeVInt

          public static boolean isNegativeVInt(byte value)

      Given the first byte of a vint/vlong, determine the sign.

      Parameters:
        `value` - the first byte
      Returns:
        is the value negative

    - #### decodeVIntSize

          public static int decodeVIntSize(byte value)

      Parse the first byte of a vint/vlong to determine the number of bytes.

      Parameters:
        `value` - the first byte of the vint/vlong
      Returns:
        the total number of bytes (1 to 9)

    - #### getVIntSize

          public static int getVIntSize(long i)

      Get the encoded length if an integer is stored in a variable-length format.

      Returns:
        the encoded length

    - #### skipFully

          public static void skipFully(DataInput in,
                                       int len)
                                throws IOException

      Skip len number of bytes in input streamin.

      Parameters:
        `in` - input stream
        `len` - number of bytes to skip
      Throws:
        `IOException` - when skipped less number of bytes

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