/*
* %CopyrightBegin%
*
* Copyright Ericsson AB 2000-2009. All Rights Reserved.
*
* The contents of this file are subject to the Erlang Public License,
* Version 1.1, (the "License"); you may not use this file except in
* compliance with the License. You should have received a copy of the
* Erlang Public License along with this software. If not, it can be
* retrieved online at http://www.erlang.org/.
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* %CopyrightEnd%
*/
package com.ericsson.otp.erlang;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
/**
* <p>
* Represents an OTP node.
* </p>
*
* <p>
* About nodenames: Erlang nodenames consist of two components, an alivename and
* a hostname separated by '@'. Additionally, there are two nodename formats:
* short and long. Short names are of the form "alive@hostname", while long
* names are of the form "[email protected]". Erlang has
* special requirements regarding the use of the short and long formats, in
* particular they cannot be mixed freely in a network of communicating nodes,
* however Jinterface makes no distinction. See the Erlang documentation for
* more information about nodenames.
* </p>
*
* <p>
* The constructors for the AbstractNode classes will create names exactly as
* you provide them as long as the name contains '@'. If the string you provide
* contains no '@', it will be treated as an alivename and the name of the local
* host will be appended, resulting in a shortname. Nodenames longer than 255
* characters will be truncated without warning.
* </p>
*
* <p>
* Upon initialization, this class attempts to read the file .erlang.cookie in
* the user's home directory, and uses the trimmed first line of the file as the
* default cookie by those constructors lacking a cookie argument. If for any
* reason the file cannot be found or read, the default cookie will be set to
* the empty string (""). The location of a user's home directory is determined
* using the system property "user.home", which may not be automatically set on
* all platforms.
* </p>
*
* <p>
* Instances of this class cannot be created directly, use one of the subclasses
* instead.
* </p>
*/
public class AbstractNode {
static String localHost = null;
String node;
String host;
String alive;
String cookie;
static String defaultCookie = null;
// Node types
static final int NTYPE_R6 = 110; // 'n' post-r5, all nodes
static final int NTYPE_R4_ERLANG = 109; // 'm' Only for source compatibility
static final int NTYPE_R4_HIDDEN = 104; // 'h' Only for source compatibility
// Node capability flags
static final int dFlagPublished = 1;
static final int dFlagAtomCache = 2;
static final int dFlagExtendedReferences = 4;
static final int dFlagDistMonitor = 8;
static final int dFlagFunTags = 0x10;
static final int dFlagDistMonitorName = 0x20; // NOT USED
static final int dFlagHiddenAtomCache = 0x40; // NOT SUPPORTED
static final int dflagNewFunTags = 0x80;
static final int dFlagExtendedPidsPorts = 0x100;
static final int dFlagExportPtrTag = 0x200; // NOT SUPPORTED
static final int dFlagBitBinaries = 0x400;
static final int dFlagNewFloats = 0x800;
int ntype = NTYPE_R6;
int proto = 0; // tcp/ip
int distHigh = 5; // Cannot talk to nodes before R6
int distLow = 5; // Cannot talk to nodes before R6
int creation = 0;
int flags = dFlagExtendedReferences | dFlagExtendedPidsPorts
| dFlagBitBinaries | dFlagNewFloats | dFlagFunTags
| dflagNewFunTags;
/* initialize hostname and default cookie */
static {
try {
localHost = InetAddress.getLocalHost().getHostName();
/*
* Make sure it's a short name, i.e. strip of everything after first
* '.'
*/
final int dot = localHost.indexOf(".");
if (dot != -1) {
localHost = localHost.substring(0, dot);
}
} catch (final UnknownHostException e) {
localHost = "localhost";
}
final String dotCookieFilename = System.getProperty("user.home")
+ File.separator + ".erlang.cookie";
BufferedReader br = null;
try {
final File dotCookieFile = new File(dotCookieFilename);
br = new BufferedReader(new FileReader(dotCookieFile));
defaultCookie = br.readLine().trim();
} catch (final IOException e) {
defaultCookie = "";
} finally {
try {
if (br != null) {
br.close();
}
} catch (final IOException e) {
}
}
}
protected AbstractNode() {
}
/**
* Create a node with the given name and the default cookie.
*/
protected AbstractNode(final String node) {
this(node, defaultCookie);
}
/**
* Create a node with the given name and cookie.
*/
protected AbstractNode(final String name, final String cookie) {
this.cookie = cookie;
final int i = name.indexOf('@', 0);
if (i < 0) {
alive = name;
host = localHost;
} else {
alive = name.substring(0, i);
host = name.substring(i + 1, name.length());
}
if (alive.length() > 0xff) {
alive = alive.substring(0, 0xff);
}
node = alive + "@" + host;
}
/**
* Get the name of this node.
*
* @return the name of the node represented by this object.
*/
public String node() {
return node;
}
/**
* Get the hostname part of the nodename. Nodenames are composed of two
* parts, an alivename and a hostname, separated by '@'. This method returns
* the part of the nodename following the '@'.
*
* @return the hostname component of the nodename.
*/
public String host() {
return host;
}
/**
* Get the alivename part of the hostname. Nodenames are composed of two
* parts, an alivename and a hostname, separated by '@'. This method returns
* the part of the nodename preceding the '@'.
*
* @return the alivename component of the nodename.
*/
public String alive() {
return alive;
}
/**
* Get the authorization cookie used by this node.
*
* @return the authorization cookie used by this node.
*/
public String cookie() {
return cookie;
}
// package scope
int type() {
return ntype;
}
// package scope
int distHigh() {
return distHigh;
}
// package scope
int distLow() {
return distLow;
}
// package scope: useless information?
int proto() {
return proto;
}
// package scope
int creation() {
return creation;
}
/**
* Set the authorization cookie used by this node.
*
* @return the previous authorization cookie used by this node.
*/
public String setCookie(final String cookie) {
final String prev = this.cookie;
this.cookie = cookie;
return prev;
}
@Override
public String toString() {
return node();
}
}
