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- spring-projects /
- spring-framework
- nes (272 sloc) 11.1 KB
- /*
- * Copyright 2002-2019 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
- *
- * https://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.util;
- import java.net.DatagramSocket;
- import java.net.InetAddress;
- import java.net.ServerSocket;
- import java.util.Random;
- import java.util.SortedSet;
- import java.util.TreeSet;
- import javax.net.ServerSocketFactory;
- /**
- * Simple utility methods for working with network sockets — for example,
- * for finding available ports on {@code localhost}.
- *
- * <p>Within this class, a TCP port refers to a port for a {@link ServerSocket};
- * whereas, a UDP port refers to a port for a {@link DatagramSocket}.
- *
- public class SocketUtils {
- /**
- * The default minimum value for port ranges used when finding an available
- * socket port.
- */
- public static final int PORT_RANGE_MIN = 1024;
- /**
- * The default maximum value for port ranges used when finding an available
- * socket port.
- */
- public static final int PORT_RANGE_MAX = 65535;
- private static final Random random = new Random(System.currentTimeMillis());
- /**
- * Although {@code SocketUtils} consists solely of static utility methods,
- * this constructor is intentionally {@code public}.
- * <h4>Rationale</h4>
- * <p>Static methods from this class may be invoked from within XML
- * configuration files using the Spring Expression Language (SpEL) and the
- * following syntax.
- * <pre><code><bean id="bean1" ... p:port="#{T(org.springframework.util.SocketUtils).findAvailableTcpPort(12000)}" /></code></pre>
- * If this constructor were {@code private}, you would be required to supply
- * the fully qualified class name to SpEL's {@code T()} function for each usage.
- * Thus, the fact that this constructor is {@code public} allows you to reduce
- * boilerplate configuration with SpEL as can be seen in the following example.
- * <pre><code><bean id="socketUtils" class="org.springframework.util.SocketUtils" />
- * <bean id="bean1" ... p:port="#{socketUtils.findAvailableTcpPort(12000)}" />
- * <bean id="bean2" ... p:port="#{socketUtils.findAvailableTcpPort(30000)}" /></code></pre>
- */
- public SocketUtils() {
- }
- /**
- * Find an available TCP port randomly selected from the range
- * [{@value #PORT_RANGE_MIN}, {@value #PORT_RANGE_MAX}].
- * @return an available TCP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableTcpPort() {
- return findAvailableTcpPort(PORT_RANGE_MIN);
- }
- /**
- * Find an available TCP port randomly selected from the range
- * [{@code minPort}, {@value #PORT_RANGE_MAX}].
- * @param minPort the minimum port number
- * @return an available TCP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableTcpPort(int minPort) {
- return findAvailableTcpPort(minPort, PORT_RANGE_MAX);
- }
- /**
- * Find an available TCP port randomly selected from the range
- * [{@code minPort}, {@code maxPort}].
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return an available TCP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableTcpPort(int minPort, int maxPort) {
- return SocketType.TCP.findAvailablePort(minPort, maxPort);
- }
- /**
- * Find the requested number of available TCP ports, each randomly selected
- * from the range [{@value #PORT_RANGE_MIN}, {@value #PORT_RANGE_MAX}].
- * @param numRequested the number of available ports to find
- * @return a sorted set of available TCP port numbers
- * @throws IllegalStateException if the requested number of available ports could not be found
- */
- public static SortedSet<Integer> findAvailableTcpPorts(int numRequested) {
- return findAvailableTcpPorts(numRequested, PORT_RANGE_MIN, PORT_RANGE_MAX);
- }
- /**
- * Find the requested number of available TCP ports, each randomly selected
- * from the range [{@code minPort}, {@code maxPort}].
- * @param numRequested the number of available ports to find
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return a sorted set of available TCP port numbers
- * @throws IllegalStateException if the requested number of available ports could not be found
- */
- public static SortedSet<Integer> findAvailableTcpPorts(int numRequested, int minPort, int maxPort) {
- return SocketType.TCP.findAvailablePorts(numRequested, minPort, maxPort);
- }
- /**
- * Find an available UDP port randomly selected from the range
- * [{@value #PORT_RANGE_MIN}, {@value #PORT_RANGE_MAX}].
- * @return an available UDP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableUdpPort() {
- return findAvailableUdpPort(PORT_RANGE_MIN);
- }
- /**
- * Find an available UDP port randomly selected from the range
- * [{@code minPort}, {@value #PORT_RANGE_MAX}].
- * @param minPort the minimum port number
- * @return an available UDP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableUdpPort(int minPort) {
- return findAvailableUdpPort(minPort, PORT_RANGE_MAX);
- }
- /**
- * Find an available UDP port randomly selected from the range
- * [{@code minPort}, {@code maxPort}].
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return an available UDP port number
- * @throws IllegalStateException if no available port could be found
- */
- public static int findAvailableUdpPort(int minPort, int maxPort) {
- return SocketType.UDP.findAvailablePort(minPort, maxPort);
- }
- /**
- * Find the requested number of available UDP ports, each randomly selected
- * from the range [{@value #PORT_RANGE_MIN}, {@value #PORT_RANGE_MAX}].
- * @param numRequested the number of available ports to find
- * @return a sorted set of available UDP port numbers
- * @throws IllegalStateException if the requested number of available ports could not be found
- */
- public static SortedSet<Integer> findAvailableUdpPorts(int numRequested) {
- return findAvailableUdpPorts(numRequested, PORT_RANGE_MIN, PORT_RANGE_MAX);
- }
- /**
- * Find the requested number of available UDP ports, each randomly selected
- * from the range [{@code minPort}, {@code maxPort}].
- * @param numRequested the number of available ports to find
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return a sorted set of available UDP port numbers
- * @throws IllegalStateException if the requested number of available ports could not be found
- */
- public static SortedSet<Integer> findAvailableUdpPorts(int numRequested, int minPort, int maxPort) {
- return SocketType.UDP.findAvailablePorts(numRequested, minPort, maxPort);
- }
- private enum SocketType {
- TCP {
- @Override
- protected boolean isPortAvailable(int port) {
- try {
- ServerSocket serverSocket = ServerSocketFactory.getDefault().createServerSocket(
- port, 1, InetAddress.getByName("localhost"));
- serverSocket.close();
- return true;
- }
- catch (Exception ex) {
- return false;
- }
- }
- },
- UDP {
- @Override
- protected boolean isPortAvailable(int port) {
- try {
- DatagramSocket socket = new DatagramSocket(port, InetAddress.getByName("localhost"));
- socket.close();
- return true;
- }
- catch (Exception ex) {
- return false;
- }
- }
- };
- /**
- * Determine if the specified port for this {@code SocketType} is
- * currently available on {@code localhost}.
- */
- protected abstract boolean isPortAvailable(int port);
- /**
- * Find a pseudo-random port number within the range
- * [{@code minPort}, {@code maxPort}].
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return a random port number within the specified range
- */
- private int findRandomPort(int minPort, int maxPort) {
- int portRange = maxPort - minPort;
- return minPort + random.nextInt(portRange + 1);
- }
- /**
- * Find an available port for this {@code SocketType}, randomly selected
- * from the range [{@code minPort}, {@code maxPort}].
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return an available port number for this socket type
- * @throws IllegalStateException if no available port could be found
- */
- int findAvailablePort(int minPort, int maxPort) {
- Assert.isTrue(minPort > 0, "'minPort' must be greater than 0");
- Assert.isTrue(maxPort >= minPort, "'maxPort' must be greater than or equal to 'minPort'");
- Assert.isTrue(maxPort <= PORT_RANGE_MAX, "'maxPort' must be less than or equal to " + PORT_RANGE_MAX);
- int portRange = maxPort - minPort;
- int candidatePort;
- int searchCounter = 0;
- do {
- if (searchCounter > portRange) {
- throw new IllegalStateException(String.format(
- "Could not find an available %s port in the range [%d, %d] after %d attempts",
- name(), minPort, maxPort, searchCounter));
- }
- candidatePort = findRandomPort(minPort, maxPort);
- searchCounter++;
- }
- while (!isPortAvailable(candidatePort));
- return candidatePort;
- }
- /**
- * Find the requested number of available ports for this {@code SocketType},
- * each randomly selected from the range [{@code minPort}, {@code maxPort}].
- * @param numRequested the number of available ports to find
- * @param minPort the minimum port number
- * @param maxPort the maximum port number
- * @return a sorted set of available port numbers for this socket type
- * @throws IllegalStateException if the requested number of available ports could not be found
- */
- SortedSet<Integer> findAvailablePorts(int numRequested, int minPort, int maxPort) {
- Assert.isTrue(minPort > 0, "'minPort' must be greater than 0");
- Assert.isTrue(maxPort > minPort, "'maxPort' must be greater than 'minPort'");
- Assert.isTrue(maxPort <= PORT_RANGE_MAX, "'maxPort' must be less than or equal to " + PORT_RANGE_MAX);
- Assert.isTrue(numRequested > 0, "'numRequested' must be greater than 0");
- Assert.isTrue((maxPort - minPort) >= numRequested,
- "'numRequested' must not be greater than 'maxPort' - 'minPort'");
- SortedSet<Integer> availablePorts = new TreeSet<>();
- int attemptCount = 0;
- while ((++attemptCount <= numRequested + 100) && availablePorts.size() < numRequested) {
- availablePorts.add(findAvailablePort(minPort, maxPort));
- }
- if (availablePorts.size() != numRequested) {
- throw new IllegalStateException(String.format(
- "Could not find %d available %s ports in the range [%d, %d]",
- numRequested, name(), minPort, maxPort));
- }
- return availablePorts;
- }
- }
- }
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