com.datastax.oss.driver.api.core.uuid.Uuids Maven / Gradle / Ivy
/*
* Copyright DataStax, Inc.
*
* 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.
*/
package com.datastax.oss.driver.api.core.uuid;
import com.datastax.oss.driver.internal.core.os.Native;
import com.datastax.oss.driver.internal.core.util.Loggers;
import com.datastax.oss.driver.shaded.guava.common.annotations.VisibleForTesting;
import com.datastax.oss.driver.shaded.guava.common.base.Charsets;
import edu.umd.cs.findbugs.annotations.NonNull;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Objects;
import java.util.Properties;
import java.util.Random;
import java.util.Set;
import java.util.SplittableRandom;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicLong;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility methods to help working with UUIDs, and more specifically, with time-based UUIDs (also
* known as Version 1 UUIDs).
*
* The algorithm to generate time-based UUIDs roughly follows the description in RFC-4122, but
* with the following adaptations:
*
*
* - Since Java does not provide direct access to the host's MAC address, that information is
* replaced with a digest of all IP addresses available on the host;
*
- The process ID (PID) isn't easily available to Java either, so it is determined by one of
* the following methods, in the order they are listed below:
*
* - If the System property
{@value PID_SYSTEM_PROPERTY} is set then the
* value to use as a PID will be read from that property;
* - Otherwise, if a native call to {@code POSIX.getpid()} is possible, then the PID will
* be read from that call;
*
- Otherwise, an attempt will be made to read the PID from JMX's {@link
* ManagementFactory#getRuntimeMXBean() RuntimeMXBean}, since most JVMs tend to use the
* JVM's PID as part of that MXBean name (however that behavior is not officially part
* of the specification, so it may not work for all JVMs);
*
- If all of the above fail, a random integer will be generated and used as a surrogate
* PID.
*
*
*
* @see JAVA-444
* @see A Universally Unique IDentifier (UUID) URN
* Namespace (RFC 4122)
*/
public final class Uuids {
/** The system property to use to force the value of the process ID ({@value}). */
public static final String PID_SYSTEM_PROPERTY = "com.datastax.oss.driver.PID";
/**
* The namespace UUID for URLs, as defined in Appendix C of RFC-4122. When using
* this namespace to create a name-based UUID, it is expected that the name part be a valid {@link
* java.net.URL URL}.
*/
public static final UUID NAMESPACE_URL = UUID.fromString("6ba7b811-9dad-11d1-80b4-00c04fd430c8");
/**
* The namespace UUID for fully-qualified domain names, as defined in Appendix C of RFC-4122. When using
* this namespace to create a name-based UUID, it is expected that the name part be a valid domain
* name.
*/
public static final UUID NAMESPACE_DNS = UUID.fromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8");
/**
* The namespace UUID for OIDs, as defined in Appendix C of RFC-4122. When using
* this namespace to create a name-based UUID, it is expected that the name part be an ISO OID.
*/
public static final UUID NAMESPACE_OID = UUID.fromString("6ba7b812-9dad-11d1-80b4-00c04fd430c8");
/**
* The namespace UUID for X.500 domain names, as defined in Appendix C of RFC-4122. When using
* this namespace to create a name-based UUID, it is expected that the name part be a valid X.500
* domain name, in DER or a text output format.
*/
public static final UUID NAMESPACE_X500 = UUID.fromString("6ba7b814-9dad-11d1-80b4-00c04fd430c8");
private static final Logger LOG = LoggerFactory.getLogger(Uuids.class);
private Uuids() {}
/**
* UUID v1 timestamps must be expressed relatively to October 15th, 1582 – the day when Gregorian
* calendar was introduced. This constant captures that moment in time expressed in milliseconds
* before the Unix epoch. It can be obtained by calling:
*
*
* Instant.parse("1582-10-15T00:00:00Z").toEpochMilli();
*
*/
private static final long START_EPOCH_MILLIS = -12219292800000L;
// Lazily initialize clock seq + node value at time of first access. Quarkus will attempt to
// initialize this class at deployment time which prevents us from just setting this value
// directly. The "node" part of the clock seq + node includes the current PID which (for
// GraalVM users) we obtain via the LLVM interop. That infrastructure isn't setup at Quarkus
// deployment time, however, thus we can't just call makeClockSeqAndNode() in an initializer.
// See JAVA-2663 for more detail on this point.
//
// Container impl adapted from Guava's memoized Supplier impl.
private static class ClockSeqAndNodeContainer {
private volatile boolean initialized = false;
private long val;
private long get() {
if (!initialized) {
synchronized (ClockSeqAndNodeContainer.class) {
if (!initialized) {
initialized = true;
val = makeClockSeqAndNode();
}
}
}
return val;
}
}
private static final ClockSeqAndNodeContainer CLOCK_SEQ_AND_NODE = new ClockSeqAndNodeContainer();
// The min and max possible lsb for a UUID.
//
// This is not 0 and all 1's because Cassandra's TimeUUIDType compares the lsb parts as signed
// byte arrays. So the min value is 8 times -128 and the max is 8 times +127.
//
// We ignore the UUID variant (namely, MIN_CLOCK_SEQ_AND_NODE has variant 2 as it should, but
// MAX_CLOCK_SEQ_AND_NODE has variant 0) because I don't trust all UUID implementations to have
// correctly set those (pycassa doesn't always for instance).
private static final long MIN_CLOCK_SEQ_AND_NODE = 0x8080808080808080L;
private static final long MAX_CLOCK_SEQ_AND_NODE = 0x7f7f7f7f7f7f7f7fL;
private static final AtomicLong lastTimestamp = new AtomicLong(0L);
private static long makeNode() {
// We don't have access to the MAC address (in pure JAVA at least) but need to generate a node
// part that identifies this host as uniquely as possible.
// The spec says that one option is to take as many sources that identify this node as possible
// and hash them together. That's what we do here by gathering all the IPs of this host as well
// as a few other sources.
try {
MessageDigest digest = MessageDigest.getInstance("MD5");
for (String address : getAllLocalAddresses()) update(digest, address);
Properties props = System.getProperties();
update(digest, props.getProperty("java.vendor"));
update(digest, props.getProperty("java.vendor.url"));
update(digest, props.getProperty("java.version"));
update(digest, props.getProperty("os.arch"));
update(digest, props.getProperty("os.name"));
update(digest, props.getProperty("os.version"));
update(digest, getProcessPiece());
byte[] hash = digest.digest();
long node = 0;
for (int i = 0; i < 6; i++) node |= (0x00000000000000ffL & (long) hash[i]) << (i * 8);
// Since we don't use the MAC address, the spec says that the multicast bit (least significant
// bit of the first byte of the node ID) must be 1.
return node | 0x0000010000000000L;
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
private static String getProcessPiece() {
Integer pid = null;
String pidProperty = System.getProperty(PID_SYSTEM_PROPERTY);
if (pidProperty != null) {
try {
pid = Integer.parseInt(pidProperty);
LOG.info("PID obtained from System property {}: {}", PID_SYSTEM_PROPERTY, pid);
} catch (NumberFormatException e) {
LOG.warn(
"Incorrect integer specified for PID in System property {}: {}",
PID_SYSTEM_PROPERTY,
pidProperty);
}
}
if (pid == null && Native.isGetProcessIdAvailable()) {
try {
pid = Native.getProcessId();
LOG.info("PID obtained through native call to getpid(): {}", pid);
} catch (Exception e) {
Loggers.warnWithException(LOG, "Native call to getpid() failed", e);
}
}
if (pid == null) {
try {
@SuppressWarnings("StringSplitter")
String pidJmx = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
pid = Integer.parseInt(pidJmx);
LOG.info("PID obtained through JMX: {}", pid);
} catch (Exception e) {
Loggers.warnWithException(LOG, "Failed to obtain PID from JMX", e);
}
}
if (pid == null) {
pid = new Random().nextInt();
LOG.warn("Could not determine PID, falling back to a random integer: {}", pid);
}
ClassLoader loader = Uuids.class.getClassLoader();
int loaderId = loader != null ? System.identityHashCode(loader) : 0;
return Integer.toHexString(pid) + Integer.toHexString(loaderId);
}
private static void update(MessageDigest digest, String value) {
if (value != null) {
digest.update(value.getBytes(Charsets.UTF_8));
}
}
private static long makeClockSeqAndNode() {
long clock = new Random(System.currentTimeMillis()).nextLong();
long node = makeNode();
long lsb = 0;
lsb |= (clock & 0x0000000000003FFFL) << 48;
lsb |= 0x8000000000000000L;
lsb |= node;
return lsb;
}
/**
* Creates a new random (version 4) UUID.
*
* This method has received a new implementation as of driver 4.10. Unlike the JDK's
* {@link UUID#randomUUID()} method, it does not use anymore the cryptographic {@link
* java.security.SecureRandom} number generator. Instead, it uses the non-cryptographic {@link
* Random} class, with a different seed at every invocation.
*
*
Using a non-cryptographic generator has two advantages:
*
*
* - UUID generation is much faster than with {@link UUID#randomUUID()};
*
- Contrary to {@link UUID#randomUUID()}, UUID generation with this method does not require
* I/O and is not a blocking call, which makes this method better suited for non-blocking
* applications.
*
*
* Of course, this method is intended for usage where cryptographic strength is not required, such
* as when generating row identifiers for insertion in the database. If you still need
* cryptographic strength, consider using {@link Uuids#random(Random)} instead, and pass an
* instance of {@link java.security.SecureRandom}.
*/
@NonNull
public static UUID random() {
return random(new Random());
}
/**
* Creates a new random (version 4) UUID using the provided {@link Random} instance.
*
* This method offers more flexibility than {@link #random()} as it allows to customize the
* {@link Random} instance to use, and also offers the possibility to reuse instances across
* successive calls. Reusing Random instances is the norm when using {@link
* java.util.concurrent.ThreadLocalRandom}, for instance; however other Random implementations may
* perform poorly under heavy thread contention.
*
*
Note: some Random implementations, such as {@link java.security.SecureRandom}, may trigger
* I/O activity during random number generation; these instances should not be used in
* non-blocking contexts.
*/
@NonNull
public static UUID random(@NonNull Random random) {
byte[] data = new byte[16];
random.nextBytes(data);
return buildUuid(data, 4);
}
/**
* Creates a new random (version 4) UUID using the provided {@link SplittableRandom} instance.
*
*
This method should be preferred to {@link #random()} when UUID generation happens in massive
* parallel computations, such as when using the ForkJoin framework. Note that {@link
* SplittableRandom} instances are not thread-safe.
*/
@NonNull
public static UUID random(@NonNull SplittableRandom random) {
byte[] data = toBytes(random.nextLong(), random.nextLong());
return buildUuid(data, 4);
}
/**
* Creates a new name-based (version 3) {@link UUID} from the given namespace UUID and the given
* string representing the name part.
*
*
Note that the given string will be converted to bytes using {@link StandardCharsets#UTF_8}.
*
* @param namespace The namespace UUID to use; cannot be null.
* @param name The name part; cannot be null.
* @throws NullPointerException if namespace or name is null.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for version 3 (MD5) is not
* available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull UUID namespace, @NonNull String name) {
Objects.requireNonNull(name, "name cannot be null");
return nameBased(namespace, name.getBytes(StandardCharsets.UTF_8));
}
/**
* Creates a new name-based (version 3) {@link UUID} from the given namespace UUID and the given
* byte array representing the name part.
*
* @param namespace The namespace UUID to use; cannot be null.
* @param name The name part; cannot be null.
* @throws NullPointerException if namespace or name is null.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for version 3 (MD5) is not
* available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull UUID namespace, @NonNull byte[] name) {
return nameBased(namespace, name, 3);
}
/**
* Creates a new name-based (version 3 or version 5) {@link UUID} from the given namespace UUID
* and the given string representing the name part.
*
*
Note that the given string will be converted to bytes using {@link StandardCharsets#UTF_8}.
*
* @param namespace The namespace UUID to use; cannot be null.
* @param name The name part; cannot be null.
* @param version The version to use, must be either 3 or 5; version 3 uses MD5 as its {@link
* MessageDigest} algorithm, while version 5 uses SHA-1.
* @throws NullPointerException if namespace or name is null.
* @throws IllegalArgumentException if version is not 3 nor 5.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for the desired version is
* not available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull UUID namespace, @NonNull String name, int version) {
Objects.requireNonNull(name, "name cannot be null");
return nameBased(namespace, name.getBytes(StandardCharsets.UTF_8), version);
}
/**
* Creates a new name-based (version 3 or version 5) {@link UUID} from the given namespace UUID
* and the given byte array representing the name part.
*
* @param namespace The namespace UUID to use; cannot be null.
* @param name The name to use; cannot be null.
* @param version The version to use, must be either 3 or 5; version 3 uses MD5 as its {@link
* MessageDigest} algorithm, while version 5 uses SHA-1.
* @throws NullPointerException if namespace or name is null.
* @throws IllegalArgumentException if version is not 3 nor 5.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for the desired version is
* not available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull UUID namespace, @NonNull byte[] name, int version) {
Objects.requireNonNull(namespace, "namespace cannot be null");
Objects.requireNonNull(name, "name cannot be null");
MessageDigest md = newMessageDigest(version);
md.update(toBytes(namespace));
md.update(name);
return buildUuid(md.digest(), version);
}
/**
* Creates a new name-based (version 3) {@link UUID} from the given byte array containing the
* namespace UUID and the name parts concatenated together.
*
*
The byte array is expected to be at least 16 bytes long.
*
* @param namespaceAndName A byte array containing the concatenated namespace UUID and name;
* cannot be null.
* @throws NullPointerException if namespaceAndName is null.
* @throws IllegalArgumentException if namespaceAndName is not at least 16 bytes
* long.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for version 3 (MD5) is not
* available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull byte[] namespaceAndName) {
return nameBased(namespaceAndName, 3);
}
/**
* Creates a new name-based (version 3 or version 5) {@link UUID} from the given byte array
* containing the namespace UUID and the name parts concatenated together.
*
*
The byte array is expected to be at least 16 bytes long.
*
* @param namespaceAndName A byte array containing the concatenated namespace UUID and name;
* cannot be null.
* @param version The version to use, must be either 3 or 5.
* @throws NullPointerException if namespaceAndName is null.
* @throws IllegalArgumentException if namespaceAndName is not at least 16 bytes
* long.
* @throws IllegalArgumentException if version is not 3 nor 5.
* @throws IllegalStateException if the {@link MessageDigest} algorithm for the desired version is
* not available on this platform.
*/
@NonNull
public static UUID nameBased(@NonNull byte[] namespaceAndName, int version) {
Objects.requireNonNull(namespaceAndName, "namespaceAndName cannot be null");
if (namespaceAndName.length < 16) {
throw new IllegalArgumentException("namespaceAndName must be at least 16 bytes long");
}
MessageDigest md = newMessageDigest(version);
md.update(namespaceAndName);
return buildUuid(md.digest(), version);
}
@NonNull
private static MessageDigest newMessageDigest(int version) {
if (version != 3 && version != 5) {
throw new IllegalArgumentException(
"Invalid name-based UUID version, expecting 3 or 5, got: " + version);
}
String algorithm = version == 3 ? "MD5" : "SHA-1";
try {
return MessageDigest.getInstance(algorithm);
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException(algorithm + " algorithm not available", e);
}
}
@NonNull
private static UUID buildUuid(@NonNull byte[] data, int version) {
// clear and set version
data[6] &= (byte) 0x0f;
data[6] |= (byte) (version << 4);
// clear and set variant to IETF
data[8] &= (byte) 0x3f;
data[8] |= (byte) 0x80;
return fromBytes(data);
}
private static UUID fromBytes(byte[] data) {
// data longer than 16 bytes will be truncated as mandated by the specs
assert data.length >= 16;
long msb = 0;
for (int i = 0; i < 8; i++) {
msb = (msb << 8) | (data[i] & 0xff);
}
long lsb = 0;
for (int i = 8; i < 16; i++) {
lsb = (lsb << 8) | (data[i] & 0xff);
}
return new UUID(msb, lsb);
}
private static byte[] toBytes(UUID uuid) {
long msb = uuid.getMostSignificantBits();
long lsb = uuid.getLeastSignificantBits();
return toBytes(msb, lsb);
}
private static byte[] toBytes(long msb, long lsb) {
byte[] out = new byte[16];
for (int i = 0; i < 8; i++) {
out[i] = (byte) (msb >> ((7 - i) * 8));
}
for (int i = 8; i < 16; i++) {
out[i] = (byte) (lsb >> ((15 - i) * 8));
}
return out;
}
/**
* Creates a new time-based (version 1) UUID.
*
*
UUIDs generated by this method are suitable for use with the {@code timeuuid} Cassandra
* type. In particular the generated UUID includes the timestamp of its generation.
*
*
Note that there is no way to provide your own timestamp. This is deliberate, as we feel that
* this does not conform to the UUID specification, and therefore don't want to encourage it
* through the API. If you want to do it anyway, use the following workaround:
*
*
* Random random = new Random();
* UUID uuid = new UUID(UUIDs.startOf(userProvidedTimestamp).getMostSignificantBits(), random.nextLong());
*
*
* If you simply need to perform a range query on a {@code timeuuid} column, use the "fake" UUID
* generated by {@link #startOf(long)} and {@link #endOf(long)}.
*
* Usage with non-blocking threads: beware that this method may block the calling thread on its
* very first invocation, because the node part of time-based UUIDs needs to be computed at that
* moment, and the computation may require the loading of native libraries. If that is a problem,
* consider invoking this method once from a thread that is allowed to block. Subsequent
* invocations are guaranteed not to block.
*/
@NonNull
public static UUID timeBased() {
return new UUID(makeMsb(getCurrentTimestamp()), CLOCK_SEQ_AND_NODE.get());
}
/**
* Creates a "fake" time-based UUID that sorts as the smallest possible version 1 UUID generated
* at the provided timestamp.
*
*
Such created UUIDs are useful in queries to select a time range of a {@code timeuuid}
* column.
*
*
The UUIDs created by this method are not unique and as such are not suitable
* for anything else than querying a specific time range. In particular, you should not insert
* such UUIDs. "True" UUIDs from user-provided timestamps are not supported (see {@link
* #timeBased()} for more explanations).
*
*
Also, the timestamp to provide as a parameter must be a Unix timestamp (as returned by
* {@link System#currentTimeMillis} or {@link Date#getTime}), and not a count of
* 100-nanosecond intervals since 00:00:00.00, 15 October 1582 (as required by RFC-4122).
*
*
In other words, given a UUID {@code uuid}, you should never call {@code
* startOf(uuid.timestamp())} but rather {@code startOf(unixTimestamp(uuid))}.
*
*
Lastly, please note that Cassandra's {@code timeuuid} sorting is not compatible with {@link
* UUID#compareTo} and hence the UUIDs created by this method are not necessarily lower bound for
* that latter method.
*
* @param timestamp the Unix timestamp for which the created UUID must be a lower bound.
* @return the smallest (for Cassandra {@code timeuuid} sorting) UUID of {@code timestamp}.
*/
@NonNull
public static UUID startOf(long timestamp) {
return new UUID(makeMsb(fromUnixTimestamp(timestamp)), MIN_CLOCK_SEQ_AND_NODE);
}
/**
* Creates a "fake" time-based UUID that sorts as the biggest possible version 1 UUID generated at
* the provided timestamp.
*
*
See {@link #startOf(long)} for explanations about the intended usage of such UUID.
*
* @param timestamp the Unix timestamp for which the created UUID must be an upper bound.
* @return the biggest (for Cassandra {@code timeuuid} sorting) UUID of {@code timestamp}.
*/
@NonNull
public static UUID endOf(long timestamp) {
long uuidTstamp = fromUnixTimestamp(timestamp + 1) - 1;
return new UUID(makeMsb(uuidTstamp), MAX_CLOCK_SEQ_AND_NODE);
}
/**
* Returns the Unix timestamp contained by the provided time-based UUID.
*
*
This method is not equivalent to {@link UUID#timestamp()}. More precisely, a version 1 UUID
* stores a timestamp that represents the number of 100-nanoseconds intervals since midnight, 15
* October 1582 and that is what {@link UUID#timestamp()} returns. This method however converts
* that timestamp to the equivalent Unix timestamp in milliseconds, i.e. a timestamp representing
* a number of milliseconds since midnight, January 1, 1970 UTC. In particular, the timestamps
* returned by this method are comparable to the timestamps returned by {@link
* System#currentTimeMillis}, {@link Date#getTime}, etc.
*
* @throws IllegalArgumentException if {@code uuid} is not a version 1 UUID.
*/
public static long unixTimestamp(@NonNull UUID uuid) {
if (uuid.version() != 1) {
throw new IllegalArgumentException(
String.format(
"Can only retrieve the unix timestamp for version 1 uuid (provided version %d)",
uuid.version()));
}
long timestamp = uuid.timestamp();
return (timestamp / 10000) + START_EPOCH_MILLIS;
}
// Use {@link System#currentTimeMillis} for a base time in milliseconds, and if we are in the same
// millisecond as the previous generation, increment the number of nanoseconds.
// However, since the precision is 100-nanosecond intervals, we can only generate 10K UUIDs within
// a millisecond safely. If we detect we have already generated that much UUIDs within a
// millisecond (which, while admittedly unlikely in a real application, is very achievable on even
// modest machines), then we stall the generator (busy spin) until the next millisecond as
// required by the RFC.
private static long getCurrentTimestamp() {
while (true) {
long now = fromUnixTimestamp(System.currentTimeMillis());
long last = lastTimestamp.get();
if (now > last) {
if (lastTimestamp.compareAndSet(last, now)) {
return now;
}
} else {
long lastMillis = millisOf(last);
// If the clock went back in time, bail out
if (millisOf(now) < millisOf(last)) {
return lastTimestamp.incrementAndGet();
}
long candidate = last + 1;
// If we've generated more than 10k uuid in that millisecond, restart the whole process
// until we get to the next millis. Otherwise, we try use our candidate ... unless we've
// been beaten by another thread in which case we try again.
if (millisOf(candidate) == lastMillis && lastTimestamp.compareAndSet(last, candidate)) {
return candidate;
}
}
}
}
@VisibleForTesting
static long fromUnixTimestamp(long tstamp) {
return (tstamp - START_EPOCH_MILLIS) * 10000;
}
private static long millisOf(long timestamp) {
return timestamp / 10000;
}
@VisibleForTesting
static long makeMsb(long timestamp) {
long msb = 0L;
msb |= (0x00000000ffffffffL & timestamp) << 32;
msb |= (0x0000ffff00000000L & timestamp) >>> 16;
msb |= (0x0fff000000000000L & timestamp) >>> 48;
msb |= 0x0000000000001000L; // sets the version to 1.
return msb;
}
private static Set getAllLocalAddresses() {
Set allIps = new HashSet<>();
try {
InetAddress localhost = InetAddress.getLocalHost();
allIps.add(localhost.toString());
// Also return the hostname if available, it won't hurt (this does a dns lookup, it's only
// done once at startup)
allIps.add(localhost.getCanonicalHostName());
InetAddress[] allMyIps = InetAddress.getAllByName(localhost.getCanonicalHostName());
if (allMyIps != null) {
for (InetAddress allMyIp : allMyIps) {
allIps.add(allMyIp.toString());
}
}
} catch (UnknownHostException e) {
// Ignore, we'll try the network interfaces anyway
}
try {
Enumeration en = NetworkInterface.getNetworkInterfaces();
if (en != null) {
while (en.hasMoreElements()) {
Enumeration enumIpAddr = en.nextElement().getInetAddresses();
while (enumIpAddr.hasMoreElements()) {
allIps.add(enumIpAddr.nextElement().toString());
}
}
}
} catch (SocketException e) {
// Ignore, if we've really got nothing so far, we'll throw an exception
}
return allIps;
}
}