ObjectId.java
package com.foxinmy.weixin4j.util;
/*
* Copyright (c) 2008-2014 MongoDB, 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.
*/
import java.net.NetworkInterface;
import java.nio.ByteBuffer;
import java.util.Date;
import java.util.Enumeration;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* <p>
* A globally unique identifier for objects.
* </p>
*
* <p>
* Consists of 12 bytes, divided as follows:
* </p>
* <table border="1">
* <caption>ObjectID layout</caption>
* <tr>
* <td>0</td>
* <td>1</td>
* <td>2</td>
* <td>3</td>
* <td>4</td>
* <td>5</td>
* <td>6</td>
* <td>7</td>
* <td>8</td>
* <td>9</td>
* <td>10</td>
* <td>11</td>
* </tr>
* <tr>
* <td colspan="4">time</td>
* <td colspan="3">machine</td>
* <td colspan="2">pid</td>
* <td colspan="3">inc</td>
* </tr>
* </table>
*
* <p>
* Instances of this class are immutable.
* </p>
*
* @mongodb.driver.manual core/object-id ObjectId
*/
public class ObjectId implements Comparable<ObjectId>, java.io.Serializable {
private static final long serialVersionUID = -4415279469780082174L;
static final Logger LOGGER = Logger.getLogger("org.bson.ObjectId");
/**
* Gets a new object id.
*
* @return the new id
*/
public static ObjectId get() {
return new ObjectId();
}
/**
* Checks if a string could be an {@code ObjectId}.
*
* @param s
* a potential ObjectId as a String.
* @return whether the string could be an object id
* @throws IllegalArgumentException
* if hexString is null
*/
public static boolean isValid(String s) {
if (s == null)
return false;
final int len = s.length();
if (len != 24)
return false;
for (int i = 0; i < len; i++) {
char c = s.charAt(i);
if (c >= '0' && c <= '9')
continue;
if (c >= 'a' && c <= 'f')
continue;
if (c >= 'A' && c <= 'F')
continue;
return false;
}
return true;
}
/**
* Constructs an ObjectId given its 12-byte binary representation.
*
* @param b
* a byte array of length 12
*/
public ObjectId(byte[] b) {
if (b.length != 12)
throw new IllegalArgumentException("need 12 bytes");
ByteBuffer bb = ByteBuffer.wrap(b);
_time = bb.getInt();
_machine = bb.getInt();
_inc = bb.getInt();
_new = false;
}
/**
* Create a new object id.
*/
public ObjectId() {
_time = (int) (System.currentTimeMillis() / 1000);
_machine = _genmachine;
_inc = _nextInc.getAndIncrement();
_new = true;
}
@Override
public int hashCode() {
int x = _time;
x += (_machine * 111);
x += (_inc * 17);
return x;
}
@Override
public boolean equals(Object o) {
if (this == o)
return true;
if (!(o instanceof ObjectId)) {
return false;
}
ObjectId other = (ObjectId) o;
return _time == other._time && _machine == other._machine
&& _inc == other._inc;
}
/**
* Converts this instance into a 24-byte hexadecimal string representation.
*
* @return a string representation of the ObjectId in hexadecimal format
*/
public String toHexString() {
final StringBuilder buf = new StringBuilder(24);
for (final byte b : toByteArray()) {
buf.append(String.format("%02x", b & 0xff));
}
return buf.toString();
}
/**
* Convert to a byte array. Note that the numbers are stored in big-endian
* order.
*
* @return the byte array
*/
public byte[] toByteArray() {
byte b[] = new byte[12];
ByteBuffer bb = ByteBuffer.wrap(b);
// by default BB is big endian like we need
bb.putInt(_time);
bb.putInt(_machine);
bb.putInt(_inc);
return b;
}
static String _pos(String s, int p) {
return s.substring(p * 2, (p * 2) + 2);
}
public String toString() {
byte b[] = toByteArray();
StringBuilder buf = new StringBuilder(24);
for (int i = 0; i < b.length; i++) {
int x = b[i] & 0xFF;
String s = Integer.toHexString(x);
if (s.length() == 1)
buf.append("0");
buf.append(s);
}
return buf.toString();
}
int _compareUnsigned(int i, int j) {
long li = 0xFFFFFFFFL;
li = i & li;
long lj = 0xFFFFFFFFL;
lj = j & lj;
long diff = li - lj;
if (diff < Integer.MIN_VALUE)
return Integer.MIN_VALUE;
if (diff > Integer.MAX_VALUE)
return Integer.MAX_VALUE;
return (int) diff;
}
public int compareTo(ObjectId id) {
if (id == null)
return -1;
int x = _compareUnsigned(_time, id._time);
if (x != 0)
return x;
x = _compareUnsigned(_machine, id._machine);
if (x != 0)
return x;
return _compareUnsigned(_inc, id._inc);
}
/**
* Gets the timestamp (number of seconds since the Unix epoch).
*
* @return the timestamp
*/
public int getTimestamp() {
return _time;
}
/**
* Gets the timestamp as a {@code Date} instance.
*
* @return the Date
*/
public Date getDate() {
return new Date(_time * 1000L);
}
/**
* Gets the current value of the auto-incrementing counter.
*
* @return the current counter value.
*/
public static int getCurrentCounter() {
return _nextInc.get();
}
final int _time;
final int _machine;
final int _inc;
boolean _new;
private static AtomicInteger _nextInc = new AtomicInteger(
(new java.util.Random()).nextInt());
private static final int _genmachine;
static {
try {
// build a 2-byte machine piece based on NICs info
int machinePiece;
{
try {
StringBuilder sb = new StringBuilder();
Enumeration<NetworkInterface> e = NetworkInterface
.getNetworkInterfaces();
while (e.hasMoreElements()) {
NetworkInterface ni = e.nextElement();
sb.append(ni.toString());
}
machinePiece = sb.toString().hashCode() << 16;
} catch (Throwable e) {
// exception sometimes happens with IBM JVM, use random
LOGGER.log(Level.WARNING, e.getMessage(), e);
machinePiece = (new Random().nextInt()) << 16;
}
LOGGER.fine("machine piece post: "
+ Integer.toHexString(machinePiece));
}
// add a 2 byte process piece. It must represent not only the JVM
// but the class loader.
// Since static var belong to class loader there could be collisions
// otherwise
final int processPiece;
{
int processId = new java.util.Random().nextInt();
try {
processId = java.lang.management.ManagementFactory
.getRuntimeMXBean().getName().hashCode();
} catch (Throwable t) {
}
ClassLoader loader = ObjectId.class.getClassLoader();
int loaderId = loader != null ? System.identityHashCode(loader)
: 0;
StringBuilder sb = new StringBuilder();
sb.append(Integer.toHexString(processId));
sb.append(Integer.toHexString(loaderId));
processPiece = sb.toString().hashCode() & 0xFFFF;
LOGGER.fine("process piece: "
+ Integer.toHexString(processPiece));
}
_genmachine = machinePiece | processPiece;
LOGGER.fine("machine : " + Integer.toHexString(_genmachine));
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}