/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.camel.impl;
import java.net.ServerSocket;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.camel.spi.UuidGenerator;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.InetAddressUtil;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* {@link org.apache.camel.spi.UuidGenerator} which is a fast implementation based on
* how <a href="http://activemq.apache.org/">Apache ActiveMQ</a> generates its UUID.
* <p/>
* This implementation is not synchronized but it leverages API which may not be accessible
* in the cloud (such as Google App Engine).
* <p/>
* The JVM system property {@link #PROPERTY_IDGENERATOR_PORT} can be used to set a specific port
* number to be used as part of the initialization process to generate unique UUID.
*/
public class ActiveMQUuidGenerator implements UuidGenerator {
// use same JVM property name as ActiveMQ
public static final String PROPERTY_IDGENERATOR_HOSTNAME = "activemq.idgenerator.hostname";
public static final String PROPERTY_IDGENERATOR_LOCALPORT = "activemq.idgenerator.localport";
public static final String PROPERTY_IDGENERATOR_PORT = "activemq.idgenerator.port";
private static final Logger LOG = LoggerFactory.getLogger(ActiveMQUuidGenerator.class);
private static final String UNIQUE_STUB;
private static int instanceCount;
private static String hostName;
private String seed;
private final AtomicLong sequence = new AtomicLong(1);
private final int length;
static {
String stub = "";
boolean canAccessSystemProps = true;
try {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPropertiesAccess();
}
} catch (SecurityException se) {
canAccessSystemProps = false;
}
if (canAccessSystemProps) {
hostName = System.getProperty(PROPERTY_IDGENERATOR_HOSTNAME);
int localPort = Integer.parseInt(System.getProperty(PROPERTY_IDGENERATOR_LOCALPORT, "0"));
int idGeneratorPort = 0;
ServerSocket ss = null;
try {
if (hostName == null) {
hostName = InetAddressUtil.getLocalHostName();
}
if (localPort == 0) {
idGeneratorPort = Integer.parseInt(System.getProperty(PROPERTY_IDGENERATOR_PORT, "0"));
LOG.trace("Using port {}", idGeneratorPort);
ss = new ServerSocket(idGeneratorPort);
localPort = ss.getLocalPort();
stub = "-" + localPort + "-" + System.currentTimeMillis() + "-";
Thread.sleep(100);
} else {
stub = "-" + localPort + "-" + System.currentTimeMillis() + "-";
}
} catch (Exception e) {
if (LOG.isTraceEnabled()) {
LOG.trace("Cannot generate unique stub by using DNS and binding to local port: " + idGeneratorPort, e);
} else {
LOG.warn("Cannot generate unique stub by using DNS and binding to local port: " + idGeneratorPort + " due " + e.getMessage());
}
// Restore interrupted state so higher level code can deal with it.
if (e instanceof InterruptedException) {
Thread.currentThread().interrupt();
}
} finally {
IOHelper.close(ss);
}
}
// fallback to use localhost
if (hostName == null) {
hostName = "localhost";
}
hostName = sanitizeHostName(hostName);
if (ObjectHelper.isEmpty(stub)) {
stub = "-1-" + System.currentTimeMillis() + "-";
}
UNIQUE_STUB = stub;
}
public ActiveMQUuidGenerator(String prefix) {
synchronized (UNIQUE_STUB) {
this.seed = prefix + UNIQUE_STUB + (instanceCount++) + "-";
// let the ID be friendly for URL and file systems
this.seed = generateSanitizedId(this.seed);
this.length = seed.length() + ("" + Long.MAX_VALUE).length();
}
}
public ActiveMQUuidGenerator() {
this("ID-" + hostName);
}
/**
* As we have to find the hostname as a side-affect of generating a unique
* stub, we allow it's easy retrieval here
*
* @return the local host name
*/
public static String getHostName() {
return hostName;
}
public static String sanitizeHostName(String hostName) {
boolean changed = false;
StringBuilder sb = new StringBuilder();
for (char ch : hostName.toCharArray()) {
// only include ASCII chars
if (ch < 127) {
sb.append(ch);
} else {
changed = true;
}
}
if (changed) {
String newHost = sb.toString();
LOG.info("Sanitized hostname from: {} to: {}", hostName, newHost);
return newHost;
} else {
return hostName;
}
}
public String generateUuid() {
StringBuilder sb = new StringBuilder(length);
sb.append(seed);
sb.append(sequence.getAndIncrement());
return sb.toString();
}
/**
* Generate a unique ID - that is friendly for a URL or file system
*
* @return a unique id
*/
public String generateSanitizedId() {
return generateSanitizedId(generateUuid());
}
/**
* Ensures that the id is friendly for a URL or file system
*
* @param id the unique id
* @return the id as file friendly id
*/
public static String generateSanitizedId(String id) {
id = id.replace(':', '-');
id = id.replace('_', '-');
id = id.replace('.', '-');
id = id.replace('/', '-');
return id;
}
}