Package com.ericsson.otp.erlang

Class OtpErlangRef

java.lang.Object
com.ericsson.otp.erlang.OtpErlangObject
com.ericsson.otp.erlang.OtpErlangRef
All Implemented Interfaces:
Serializable, Cloneable
public class OtpErlangRef extends OtpErlangObject
Provides a Java representation of Erlang refs. There are two styles of Erlang refs, old style (one id value) and new style (array of id values). This class manages both types.
See Also:

  • Constructor Details

    • OtpErlangRef

      @Deprecated public OtpErlangRef(OtpLocalNode self)
      Deprecated.
      use OtpLocalNode:createRef() instead
      Create a unique Erlang ref belonging to the local node.
      Parameters:
      self - the local node.

    • OtpErlangRef

      public OtpErlangRef(OtpInputStream buf) throws OtpErlangDecodeException
      Create an Erlang ref from a stream containing a ref encoded in Erlang external format.
      Parameters:
      buf - the stream containing the encoded ref.
      Throws:
      OtpErlangDecodeException - if the buffer does not contain a valid external representation of an Erlang ref.

    • OtpErlangRef

      public OtpErlangRef(String node, int id, int creation)
      Create an old style Erlang ref from its components.
      Parameters:
      node - the nodename.
      id - an arbitrary number. Only the low order 18 bits will be used.
      creation - another arbitrary number.

    • OtpErlangRef

      public OtpErlangRef(String node, int[] ids, int creation)
      Create a new style Erlang ref from its components.
      Parameters:
      node - the nodename.
      ids - an array of arbitrary numbers. Only the low order 18 bits of the first number will be used. If the array contains only one number, an old style ref will be written instead. At most three numbers will be read from the array.
      creation - node incarnation number. Avoid values 0 to 3.

    • OtpErlangRef

      public OtpErlangRef(int tag, String node, int[] ids, int creation)
      Create a new(er) style Erlang ref from its components.
      Parameters:
      tag - the external format to be compliant with. OtpExternal.newRefTag where only a subset of the bits are used (see other constructor) OtpExternal.newerRefTag where all bits of ids and creation are used. newerPortTag can only be decoded by OTP-19 and newer.
      node - the nodename.
      ids - an array of arbitrary numbers. At most three numbers will be read from the array.
      creation - another arbitrary number.

  • Method Details

    • tag

      protected int tag()

    • id

      public int id()
      Get the id number from the ref. Old style refs have only one id number. If this is a new style ref, the first id number is returned.
      Returns:
      the id number from the ref.

    • ids

      public int[] ids()
      Get the array of id numbers from the ref. If this is an old style ref, the array is of length 1. If this is a new style ref, the array has length 3-5.
      Returns:
      the array of id numbers from the ref.

    • isNewRef

      public boolean isNewRef()
      Determine whether this is a new style ref.
      Returns:
      true if this ref is a new style ref, false otherwise.

    • creation

      public int creation()
      Get the creation number from the ref.
      Returns:
      the creation number from the ref.

    • node

      public String node()
      Get the node name from the ref.
      Returns:
      the node name from the ref.

    • toString

      public String toString()
      Get the string representation of the ref. Erlang refs are printed as #Ref<node.id>
      Specified by:
      toString in class OtpErlangObject
      Returns:
      the string representation of the ref.

    • encode

      public void encode(OtpOutputStream buf)
      Convert this ref to the equivalent Erlang external representation.
      Specified by:
      encode in class OtpErlangObject
      Parameters:
      buf - an output stream to which the encoded ref should be written.

    • equals

      public boolean equals(Object o)
      Determine if two refs are equal. Refs are equal if their components are equal. New refs and old refs are considered equal if the node, creation and first id number are equal.
      Specified by:
      equals in class OtpErlangObject
      Parameters:
      o - the other ref to compare to.
      Returns:
      true if the refs are equal, false otherwise.

    • doHashCode

      protected int doHashCode()
      Compute the hashCode value for a given ref. This function is compatible with equal.
      Overrides:
      doHashCode in class OtpErlangObject
      Returns:
      the hashCode of the node.

    • clone

      public Object clone()
      Overrides:
      clone in class OtpErlangObject