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/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2000-2016. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
package com.ericsson.otp.erlang;
/**
* Provides a Java representation of Erlang PIDs. PIDs represent Erlang
* processes and consist of a nodename and a number of integers.
*/
public class OtpErlangPid extends OtpErlangObject implements Comparable<Object> {
// don't change this!
private static final long serialVersionUID = 1664394142301803659L;
private final int tag;
private final String node;
private final int id;
private final int serial;
private final int creation;
/**
* Create a unique Erlang PID belonging to the local node.
*
* @param self
* the local node.
*
* @deprecated use OtpLocalNode:createPid() instead
*/
@Deprecated
public OtpErlangPid(final OtpLocalNode self) {
final OtpErlangPid p = self.createPid();
tag = p.tag;
id = p.id;
serial = p.serial;
creation = p.creation;
node = p.node;
}
/**
* Create an Erlang PID from a stream containing a PID encoded in Erlang
* external format.
*
* @param buf
* the stream containing the encoded PID.
*
* @exception OtpErlangDecodeException
* if the buffer does not contain a valid external
* representation of an Erlang PID.
*/
public OtpErlangPid(final OtpInputStream buf)
throws OtpErlangDecodeException {
final OtpErlangPid p = buf.read_pid();
tag = p.tag;
node = p.node();
id = p.id();
serial = p.serial();
creation = p.creation();
}
/**
* Create an Erlang pid from its components.
*
* @param node
* the nodename.
*
* @param id
* an arbitrary number. Only the low order 15 bits will be used.
*
* @param serial
* another arbitrary number. Only the low order 13 bits will be
* used.
*
* @param creation
* yet another arbitrary number. Ony the low order 2 bits will
* be used.
*/
public OtpErlangPid(final String node, final int id, final int serial,
final int creation) {
this(OtpExternal.pidTag, node, id, serial, creation);
}
/**
* Create an Erlang pid from its components.
*
* @param tag
* the external format to be compliant with
* OtpExternal.pidTag where only a subset of the bits are significant (see other constructor).
* OtpExternal.newPidTag where all 32 bits of id,serial and creation are significant.
* newPidTag can only be decoded by OTP-19 and newer.
* @param node
* the nodename.
*
* @param id
* an arbitrary number.
*
* @param serial
* another arbitrary number.
*
* @param creation
* yet another arbitrary number.
*/
protected OtpErlangPid(final int tag, final String node, final int id,
final int serial, final int creation) {
this.tag = tag;
this.node = node;
if (tag == OtpExternal.pidTag) {
this.id = id & 0x7fff; // 15 bits
this.serial = serial & 0x1fff; // 13 bits
this.creation = creation & 0x03; // 2 bits
}
else { // allow all 32 bits for newPidTag
this.id = id;
this.serial = serial;
this.creation = creation;
}
}
protected int tag() {
return tag;
}
/**
* Get the serial number from the PID.
*
* @return the serial number from the PID.
*/
public int serial() {
return serial;
}
/**
* Get the id number from the PID.
*
* @return the id number from the PID.
*/
public int id() {
return id;
}
/**
* Get the creation number from the PID.
*
* @return the creation number from the PID.
*/
public int creation() {
return creation;
}
/**
* Get the node name from the PID.
*
* @return the node name from the PID.
*/
public String node() {
return node;
}
/**
* Get the string representation of the PID. Erlang PIDs are printed as
* #Pid<node.id.serial>
*
* @return the string representation of the PID.
*/
@Override
public String toString() {
return "#Pid<" + node.toString() + "." + id + "." + serial + ">";
}
/**
* Convert this PID to the equivalent Erlang external representation.
*
* @param buf
* an output stream to which the encoded PID should be written.
*/
@Override
public void encode(final OtpOutputStream buf) {
buf.write_pid(this);
}
/**
* Determine if two PIDs are equal. PIDs are equal if their components are
* equal.
*
* @param o
* the other PID to compare to.
*
* @return true if the PIDs are equal, false otherwise.
*/
@Override
public boolean equals(final Object o) {
if (!(o instanceof OtpErlangPid)) {
return false;
}
final OtpErlangPid pid = (OtpErlangPid) o;
return creation == pid.creation && serial == pid.serial && id == pid.id
&& node.compareTo(pid.node) == 0;
}
@Override
protected int doHashCode() {
final OtpErlangObject.Hash hash = new OtpErlangObject.Hash(5);
hash.combine(creation, serial);
hash.combine(id, node.hashCode());
return hash.valueOf();
}
public int compareTo(final Object o) {
if (!(o instanceof OtpErlangPid)) {
return -1;
}
final OtpErlangPid pid = (OtpErlangPid) o;
if (creation == pid.creation) {
if (serial == pid.serial) {
if (id == pid.id) {
return node.compareTo(pid.node);
}
return id - pid.id;
}
return serial - pid.serial;
}
return creation - pid.creation;
}
}
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