/*
* Copyright 2005-2011 the original author or authors.
*
* 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 org.springframework.ws.transport.support;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.util.Random;
import org.springframework.util.Assert;
/**
* Utility class that finds free BSD ports for use in testing scenario's.
*
* @author Ben Hale
* @author Arjen Poutsma
*/
public abstract class FreePortScanner {
private static final int MIN_SAFE_PORT = 1024;
private static final int MAX_PORT = 65535;
private static final Random random = new Random();
/**
* Returns the number of a free port in the default range.
*/
public static int getFreePort() {
return getFreePort(MIN_SAFE_PORT, MAX_PORT);
}
/**
* Returns the number of a free port in the given range.
*/
public static int getFreePort(int minPort, int maxPort) {
Assert.isTrue(minPort > 0, "'minPort' must be larger than 0");
Assert.isTrue(maxPort > minPort, "'maxPort' must be larger than minPort");
int portRange = maxPort - minPort;
int candidatePort;
int searchCounter = 0;
do {
if (++searchCounter > portRange) {
throw new IllegalStateException(
String.format("There were no ports available in the range %d to %d", minPort, maxPort));
}
candidatePort = getRandomPort(minPort, portRange);
}
while (!isPortAvailable(candidatePort));
return candidatePort;
}
private static int getRandomPort(int minPort, int portRange) {
return minPort + random.nextInt(portRange);
}
private static boolean isPortAvailable(int port) {
ServerSocket serverSocket;
try {
serverSocket = new ServerSocket();
}
catch (IOException ex) {
throw new IllegalStateException("Unable to create ServerSocket.", ex);
}
try {
InetSocketAddress sa = new InetSocketAddress(port);
serverSocket.bind(sa);
return true;
}
catch (IOException ex) {
return false;
}
finally {
try {
serverSocket.close();
}
catch (IOException ex) {
// ignore
}
}
}
}