Package io.crums.model

Class HashUtc

java.lang.Object
io.crums.model.HashUtc
Direct Known Subclasses:
Crum, TreeRef
public class HashUtc
extends java.lang.Object
A 32 byte hash, plus an 8 byte long representing a witness time.

  • Field Summary

    Fields
    Modifier and Type Field Description
    protected java.nio.ByteBuffer data
    The positional state is never modified, not even momentarily.
    static int DATA_SIZE
    Data size is Constants.HASH_WIDTH + Long.BYTES.
    static java.util.Comparator<HashUtc> HASH_COMPARATOR
    Compares 2 instances solely by hash.
    static long INCEPTION_UTC
    Version 1 concept date.
    static long RUN_MAX_UTC
    As a sanity check on data, the maximum UTC is bounded by 1 year from class-load time.

  • Constructor Summary

    Constructors
    Constructor Description
    HashUtc​(byte[] hash, long utc)
    Creates a new instance with the given fields.
    HashUtc​(java.nio.ByteBuffer data)
    Creates a new instance with the given data buffer.
    HashUtc​(java.nio.ByteBuffer hash, long utc)
    Creates a new instance with the given fields.

  • Method Summary

    Modifier and Type Method Description
    boolean equals​(java.lang.Object o)
    Instances are equal iff their hash()s and utc()s are equal.
    boolean equalsHashUtc​(HashUtc o)
    Typed equals(Object).
    java.nio.ByteBuffer hash()
    Returns a read-only buffer whose remaining bytes are the hash.
    int hashCode()
    Consistent with equals.
    boolean hashEquals​(HashUtc o)
    Tests if this instance's hash is the same as the other.
    java.lang.String hashHex()
    Returns the hash in its hexadecimal representation.
    protected void sanityCheckUtc​(long utc)
    Bounds checks the given utc as one that could possibly be issued by the service.
    java.nio.ByteBuffer serialForm()
    Returns the instance's serialized representation as a read-only buffer.
    java.lang.String toString()
    For debug purposes.
    long utc()
    Time in UTC milliseconds.
    static java.nio.ByteBuffer writeToBuffer​(byte[] hash, long utc, java.nio.ByteBuffer out)
    Serializes the given hash/utc tuple to the given out buffer.
    static java.nio.ByteBuffer writeToBuffer​(java.nio.ByteBuffer hash, long utc, java.nio.ByteBuffer out)
    Serializes the given hash/utc tuple to the given out buffer.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • HASH_COMPARATOR

      public static final java.util.Comparator<HashUtc> HASH_COMPARATOR
      Compares 2 instances solely by hash.

    • INCEPTION_UTC

      public static final long INCEPTION_UTC
      Version 1 concept date. We're ditching our existing data, so this'll be okay. A claim to a hash witnessed in the form of a crum before this date (July 1, 2020 12:00:00 PM GMT) is nonsense. The constructor disallows it.
      See Also:
      RUN_MAX_UTC, Constant Field Values

    • RUN_MAX_UTC

      public static final long RUN_MAX_UTC
      As a sanity check on data, the maximum UTC is bounded by 1 year from class-load time. So this means you can't leave a server running forever. Not unrealistic.
      See Also:
      INCEPTION_UTC

    • DATA_SIZE

      public static final int DATA_SIZE
      Data size is Constants.HASH_WIDTH + Long.BYTES.
      See Also:
      Constant Field Values

    • data

      protected final java.nio.ByteBuffer data
      The positional state is never modified, not even momentarily. (If a subclass does, then it'll likely have undefined concurrent behavior.)

  • Constructor Details

    • HashUtc

      public HashUtc​(java.nio.ByteBuffer data)
      Creates a new instance with the given data buffer.
      Parameters:
      data - the caller agrees not to modify the given buffer in any way; otherwise the immutability the immutability guarantee is for naught.
      See Also:
      serialForm()

    • HashUtc

      public HashUtc​(byte[] hash, long utc)
      Creates a new instance with the given fields.
      See Also:
      INCEPTION_UTC, RUN_MAX_UTC

    • HashUtc

      public HashUtc​(java.nio.ByteBuffer hash, long utc)
      Creates a new instance with the given fields.
      See Also:
      INCEPTION_UTC, RUN_MAX_UTC

  • Method Details

    • writeToBuffer

      public static java.nio.ByteBuffer writeToBuffer​(byte[] hash, long utc, java.nio.ByteBuffer out)
      Serializes the given hash/utc tuple to the given out buffer. The point of this method is to centralize serialization/deserializaton format (since it's changed).
      Parameters:
      hash - Constants.HASH_WIDTH bytes long
      utc - (not bounds checked)
      out - assumed to have remaining bytes. On return, assuming good arguments, the position is advanced DATA_SIZE bytes.
      Returns:
      the out argument (unflipped)
      See Also:
      constructor for deserialization., writeToBuffer(ByteBuffer, long, ByteBuffer)

    • writeToBuffer

      public static java.nio.ByteBuffer writeToBuffer​(java.nio.ByteBuffer hash, long utc, java.nio.ByteBuffer out)
      Serializes the given hash/utc tuple to the given out buffer. The point of this method is to centralize serialization/deserializaton format (since it's changed).
      Parameters:
      hash - Constants.HASH_WIDTH remaning bytes
      utc - (not bounds checked)
      out - assumed to have remaining bytes. On return, assuming good arguments, the position is advanced DATA_SIZE bytes.
      Returns:
      the out argument (unflipped)
      See Also:
      constructor for deserialization., writeToBuffer(byte[], long, ByteBuffer)

    • sanityCheckUtc

      protected final void sanityCheckUtc​(long utc)
      Bounds checks the given utc as one that could possibly be issued by the service.

    • hash

      public java.nio.ByteBuffer hash()
      Returns a read-only buffer whose remaining bytes are the hash. (It's capacity is in fact greater.)

    • hashHex

      public java.lang.String hashHex()
      Returns the hash in its hexadecimal representation.

    • utc

      public long utc()
      Time in UTC milliseconds.

    • serialForm

      public java.nio.ByteBuffer serialForm()
      Returns the instance's serialized representation as a read-only buffer.
      Returns:
      a buffer with DATA_SIZE remaining bytes.
      See Also:
      #Crum(ByteBuffer)

    • equals

      public final boolean equals​(java.lang.Object o)
      Instances are equal iff their hash()s and utc()s are equal.
      Overrides:
      equals in class java.lang.Object
      See Also:
      equalsHashUtc(HashUtc)

    • equalsHashUtc

      public final boolean equalsHashUtc​(HashUtc o)
      Typed equals(Object).

    • hashEquals

      public final boolean hashEquals​(HashUtc o)
      Tests if this instance's hash is the same as the other.

    • hashCode

      public final int hashCode()
      Consistent with equals. And efficient. (We lean on the randomness of cryptographic hashes).
      Overrides:
      hashCode in class java.lang.Object

    • toString

      public java.lang.String toString()
      For debug purposes.
      Overrides:
      toString in class java.lang.Object