/*
* 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.usergrid.cassandra;
import java.io.IOException;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.TreeSet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Finds currently available server ports.
*
* @author <a href="http://mina.apache.org">Apache MINA Project</a>
* @see <a href="http://www.iana.org/assignments/port-numbers">IANA.org</a>
*/
public class AvailablePortFinder {
private static final Logger logger = LoggerFactory.getLogger( AvailablePortFinder.class );
/** The minimum number of server port number. */
public static final int MIN_PORT_NUMBER = 1;
/** The maximum number of server port number. */
public static final int MAX_PORT_NUMBER = 49151;
/** Creates a new instance. */
private AvailablePortFinder() {
// Do nothing
}
/**
* Returns the {@link Set} of currently available port numbers ({@link Integer}). This method is identical to
* <code>getAvailablePorts(MIN_PORT_NUMBER, MAX_PORT_NUMBER)</code>.
* <p/>
* WARNING: this can take a very long time.
*/
public static Set<Integer> getAvailablePorts() {
return getAvailablePorts( MIN_PORT_NUMBER, MAX_PORT_NUMBER );
}
/**
* Gets an available port, selected by the system.
*
* @throws NoSuchElementException if there are no ports available
*/
public static int getNextAvailable() {
ServerSocket serverSocket = null;
try {
// Here, we simply return an available port found by the system
serverSocket = new ServerSocket( 0 );
int port = serverSocket.getLocalPort();
// Don't forget to close the socket...
serverSocket.close();
return port;
}
catch ( IOException ioe ) {
throw new NoSuchElementException( ioe.getMessage() );
}
}
/**
* Gets the next available port starting at a port.
*
* @param fromPort the port to scan for availability
*
* @throws NoSuchElementException if there are no ports available
*/
public static int getNextAvailable( int fromPort ) {
if ( fromPort < MIN_PORT_NUMBER || fromPort > MAX_PORT_NUMBER ) {
throw new IllegalArgumentException( "Invalid start port: " + fromPort );
}
for ( int i = fromPort; i <= MAX_PORT_NUMBER; i++ ) {
if ( available( i ) ) {
return i;
}
}
throw new NoSuchElementException( "Could not find an available port " + "above " + fromPort );
}
/**
* Checks to see if a specific port is available.
*
* @param port the port to check for availability
*/
public static boolean available( int port ) {
if ( port < MIN_PORT_NUMBER || port > MAX_PORT_NUMBER ) {
throw new IllegalArgumentException( "Invalid start port: " + port );
}
ServerSocket ss = null;
DatagramSocket ds = null;
try {
// Jackson: It seems like the code below intends to
// setReuseAddress(true), but that needs to be set before the bind.
// The constructor for the ServerSocket(int) will bind, so not sure
// how it would have been working as intended previously.
// Changing ServerSocket constructor to use default constructor,
// this would be unbound, then set the socket reuse, and
// call the bind separately
//ss = new ServerSocket( port );
ss = new ServerSocket();
ss.setReuseAddress( true );
ss.bind(new InetSocketAddress((InetAddress) null, port), 0);
// Unlike ServerSocket, the default constructor of DatagramSocket
// will bound. To create an unbound DatagramSocket, use null address
//ds = new DatagramSocket( port );
ds = new DatagramSocket(null);
ds.setReuseAddress( true );
ds.bind(new InetSocketAddress((InetAddress) null, port));
logger.info("port {} available", port);
return true;
}
catch ( IOException e ) {
// Do nothing
}
finally {
if ( ds != null ) {
ds.close();
}
if ( ss != null ) {
try {
ss.close();
}
catch ( IOException e ) {
/* should not be thrown */
}
}
}
logger.info("port {} unavailable", port);
return false;
}
/**
* Returns the {@link Set} of currently avaliable port numbers ({@link Integer}) between the specified port range.
*
* @throws IllegalArgumentException if port range is not between {@link #MIN_PORT_NUMBER} and {@link
* #MAX_PORT_NUMBER} or <code>fromPort</code> if greater than <code>toPort</code>.
*/
public static Set<Integer> getAvailablePorts( int fromPort, int toPort ) {
if ( fromPort < MIN_PORT_NUMBER || toPort > MAX_PORT_NUMBER || fromPort > toPort ) {
throw new IllegalArgumentException( "Invalid port range: " + fromPort + " ~ " + toPort );
}
Set<Integer> result = new TreeSet<Integer>();
for ( int i = fromPort; i <= toPort; i++ ) {
ServerSocket s = null;
try {
s = new ServerSocket( i );
result.add(i);
}
catch ( IOException e ) {
// Do nothing
}
finally {
if ( s != null ) {
try {
s.close();
}
catch ( IOException e ) {
/* should not be thrown */
}
}
}
}
return result;
}
}