OtpErlangRef (Java-Erlang Interface Library)
Date: 2017-12-11

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## com.ericsson.otp.erlang
Class OtpErlangRef

    java.lang.Object
      com.ericsson.otp.erlang.OtpErlangObject
          com.ericsson.otp.erlang.OtpErlangRef

All Implemented Interfaces:
  java.io.Serializable, java.lang.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:
  Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.ericsson.otp.erlang.OtpErlangObject
`OtpErlangObject.Hash`

Field Summary

Fields inherited from class com.ericsson.otp.erlang.OtpErlangObject
`hashCodeValue`

Constructor Summary
`OtpErlangRef(int tag, java.lang.String node, int[] ids, int creation)` Create a new(er) style Erlang ref from its components.
`OtpErlangRef(OtpInputStream buf)` Create an Erlang ref from a stream containing a ref encoded in Erlang external format.
`OtpErlangRef(OtpLocalNode self)` Deprecated. use OtpLocalNode:createRef() instead
`OtpErlangRef(java.lang.String node, int[] ids, int creation)` Create a new style Erlang ref from its components.
`OtpErlangRef(java.lang.String node, int id, int creation)` Create an old style Erlang ref from its components.

Method Summary
`java.lang.Object` | `clone()`
`int` | `creation()` Get the creation number from the ref.
`protected int` | `doHashCode()` Compute the hashCode value for a given ref.
`void` | `encode(OtpOutputStream buf)` Convert this ref to the equivalent Erlang external representation.
`boolean` | `equals(java.lang.Object o)` Determine if two refs are equal.
`int` | `id()` Get the id number from the ref.
`int[]` | `ids()` Get the array of id numbers from the ref.
`boolean` | `isNewRef()` Determine whether this is a new style ref.
`java.lang.String` | `node()` Get the node name from the ref.
`protected int` | `tag()`
`java.lang.String` | `toString()` Get the string representation of the ref.

Methods inherited from class com.ericsson.otp.erlang.OtpErlangObject
`bind, decode, hashCode, match`

Methods inherited from class java.lang.Object
`finalize, getClass, notify, notifyAll, wait, wait, wait`

Constructor Detail

### 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(java.lang.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(java.lang.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` - another arbitrary number. Only the low order 2 bits will be used.

### OtpErlangRef

    public OtpErlangRef(int tag,
                        java.lang.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 Detail

### 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.

  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 java.lang.String node()

  Get the node name from the ref.

  Returns:
    the node name from the ref.

### toString

    public java.lang.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(java.lang.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 numnber 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 java.lang.Object clone()

  Overrides:
    `clone` in class `OtpErlangObject`

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