Module org.eclipse.jgit
Package org.eclipse.jgit.lib

Class AbbreviatedObjectId

java.lang.Object
org.eclipse.jgit.lib.AbbreviatedObjectId
All Implemented Interfaces:
Serializable
public final class AbbreviatedObjectId extends Object implements Serializable
A prefix abbreviation of an ObjectId.

Sometimes Git produces abbreviated SHA-1 strings, using sufficient leading digits from the ObjectId name to still be unique within the repository the string was generated from. These ids are likely to be unique for a useful period of time, especially if they contain at least 6-10 hex digits.

This class converts the hex string into a binary form, to make it more efficient for matching against an object.

See Also:

  • Method Details

    • isId

      public static final boolean isId(String id)
      Test a string of characters to verify it is a hex format.

      If true the string can be parsed with fromString(String).

      Parameters:
      id - the string to test.
      Returns:
      true if the string can converted into an AbbreviatedObjectId.

    • fromString

      public static final AbbreviatedObjectId fromString(byte[] buf, int offset, int end)
      Convert an AbbreviatedObjectId from hex characters (US-ASCII).
      Parameters:
      buf - the US-ASCII buffer to read from.
      offset - position to read the first character from.
      end - one past the last position to read (end-offset is the length of the string).
      Returns:
      the converted object id.

    • fromObjectId

      public static final AbbreviatedObjectId fromObjectId(AnyObjectId id)
      Convert an AbbreviatedObjectId from an AnyObjectId.

      This method copies over all bits of the Id, and is therefore complete (see isComplete()).

      Parameters:
      id - the ObjectId to convert from.
      Returns:
      the converted object id.

    • fromString

      public static final AbbreviatedObjectId fromString(String str)
      Convert an AbbreviatedObjectId from hex characters.
      Parameters:
      str - the string to read from. Must be <= 40 characters.
      Returns:
      the converted object id.

    • length

      public int length()
      Get number of hex digits appearing in this id.
      Returns:
      number of hex digits appearing in this id.

    • isComplete

      public boolean isComplete()
      Whether this ObjectId is actually a complete id.
      Returns:
      true if this ObjectId is actually a complete id.

    • toObjectId

      public ObjectId toObjectId()
      A complete ObjectId; null if isComplete() is false
      Returns:
      a complete ObjectId; null if isComplete() is false

    • prefixCompare

      public final int prefixCompare(AnyObjectId other)
      Compares this abbreviation to a full object id.
      Parameters:
      other - the other object id.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • prefixCompare

      public final int prefixCompare(byte[] bs, int p)
      Compare this abbreviation to a network-byte-order ObjectId.
      Parameters:
      bs - array containing the other ObjectId in network byte order.
      p - position within bs to start the compare at. At least 20 bytes, starting at this position are required.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • prefixCompare

      public final int prefixCompare(int[] bs, int p)
      Compare this abbreviation to a network-byte-order ObjectId.
      Parameters:
      bs - array containing the other ObjectId in network byte order.
      p - position within bs to start the compare at. At least 5 ints, starting at this position are required.
      Returns:
      <0 if this abbreviation names an object that is less than other; 0 if this abbreviation exactly matches the first length() digits of other.name(); >0 if this abbreviation names an object that is after other.

    • getFirstByte

      public final int getFirstByte()
      Get value for a fan-out style map, only valid of length >= 2.
      Returns:
      value for a fan-out style map, only valid of length >= 2.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • name

      public final String name()
      Get string form of the abbreviation, in lower case hexadecimal.
      Returns:
      string form of the abbreviation, in lower case hexadecimal.

    • toString

      public String toString()
      Overrides:
      toString in class Object