Package io.vertx.ext.auth.prng

Interface VertxContextPRNG

  • All Known Implementing Classes:
    PRNG
    public interface VertxContextPRNG
    A secure non blocking random number generator isolated to the current context. The PRNG is bound to the vert.x context and setup to close when the context shuts down.

    When applicable, use of VertxContextPRNG rather than create new PRNG objects is helpful to keep the system entropy usage to the minimum avoiding potential blocking across the application.

    The use of VertxContextPRNG is particularly appropriate when multiple handlers use random numbers.

    Author:
    Paulo Lopes

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void close()
      stop seeding the PRNG
      static VertxContextPRNG current()
      Get or create a secure non blocking random number generator using the current vert.x context.
      static VertxContextPRNG current​(Context context)
      Get or create a secure non blocking random number generator using the provided vert.x context.
      static VertxContextPRNG current​(Vertx vertx)
      Get or create a secure non blocking random number generator using the current vert.x instance.
      boolean nextBoolean()
      Returns a secure random boolean
      void nextBytes​(byte[] bytes)
      Fills the given byte array with random bytes.
      double nextDouble()
      Returns a secure random double value.
      float nextFloat()
      Returns a secure random float value.
      double nextGaussian()
      Returns a secure random double value.
      int nextInt()
      Returns a secure random int
      int nextInt​(int bound)
      Returns a secure random int, between 0 (inclusive) and the specified bound (exclusive).
      long nextLong()
      Returns a secure random long
      String nextString​(int length)
      Returns a Base64 url encoded String of random data with the given length.

    • Method Detail

      • current

        static VertxContextPRNG current()
        Get or create a secure non blocking random number generator using the current vert.x context. If there is no current context (i.e.: not running on the eventloop) then a IllegalStateException is thrown.

        Note, if a context isn't allowed to be used, for example, exceptions are thrown on getting and putting data, the VertxContextPRNG falls back to instantiate a new instance of the PRNG per call.

        Returns:
        A secure non blocking random number generator.
        Throws:
        IllegalStateException - when there is no Context instance available.

      • current

        static VertxContextPRNG current​(Context context)
        Get or create a secure non blocking random number generator using the provided vert.x context. This method will not throw an exception.

        Note, if a context isn't allowed to be used, for example, exceptions are thrown on getting and putting data, the VertxContextPRNG falls back to instantiate a new instance of the PRNG per call.

        Parameters:
        context - a Vert.x context.
        Returns:
        A secure non blocking random number generator
        Throws:
        IllegalStateException - when there is no Vertx instance available.

      • current

        static VertxContextPRNG current​(Vertx vertx)
        Get or create a secure non blocking random number generator using the current vert.x instance. Since the context might be different this method will attempt to use the current context first if available and then fall back to create a new instance of the PRNG.

        Note, if a context isn't allowed to be used, for example, exceptions are thrown on getting and putting data, the VertxContextPRNG falls back to instantiate a new instance of the PRNG per call.

        Parameters:
        vertx - a Vert.x instance.
        Returns:
        A secure non blocking random number generator.

      • close

        void close()
        stop seeding the PRNG

      • nextBytes

        void nextBytes​(byte[] bytes)
        Fills the given byte array with random bytes.
        Parameters:
        bytes - a byte array.

      • nextString

        String nextString​(int length)
        Returns a Base64 url encoded String of random data with the given length. The length parameter refers to the length of the String before the encoding step.
        Parameters:
        length - the desired string length before Base64 encoding.
        Returns:
        A base 64 encoded string.

      • nextInt

        int nextInt()
        Returns a secure random int
        Returns:
        random int.

      • nextInt

        int nextInt​(int bound)
        Returns a secure random int, between 0 (inclusive) and the specified bound (exclusive).
        Parameters:
        bound - the upper bound (exclusive), which must be positive.
        Returns:
        random int.

      • nextBoolean

        boolean nextBoolean()
        Returns a secure random boolean
        Returns:
        random boolean.

      • nextLong

        long nextLong()
        Returns a secure random long
        Returns:
        random long.

      • nextFloat

        float nextFloat()
        Returns a secure random float value. The value is uniformly distributed between 0.0 and 1.0
        Returns:
        random float.

      • nextDouble

        double nextDouble()
        Returns a secure random double value. The value is uniformly distributed between 0.0 and 1.0
        Returns:
        random double.

      • nextGaussian

        double nextGaussian()
        Returns a secure random double value. The value is Gaussian ("normally") distributed with mean 0.0 and standard deviation 1.0
        Returns:
        random double.