Package net.devh.boot.grpc.common.util

Class SocketUtils

java.lang.Object
net.devh.boot.grpc.common.util.SocketUtils
public class SocketUtils extends Object
Simple utility methods for working with network sockets — for example, for finding available ports on localhost.

Within this class, a TCP port refers to a port for a ServerSocket; whereas, a UDP port refers to a port for a DatagramSocket.

SocketUtils was introduced in Spring Framework 4.0, primarily to assist in writing integration tests which start an external server on an available random port. However, these utilities make no guarantee about the subsequent availability of a given port and are therefore unreliable. Instead of using SocketUtils to find an available local port for a server, it is recommended that you rely on a server's ability to start on a random port that it selects or is assigned by the operating system. To interact with that server, you should query the server for the port it is currently using.

Since:
4.0

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    PORT_RANGE_MAX
    The default maximum value for port ranges used when finding an available socket port.
    static final int
    PORT_RANGE_MIN
    The default minimum value for port ranges used when finding an available socket port.

  • Constructor Summary

    Constructors
    Constructor
    Description
    SocketUtils()
    Although SocketUtils consists solely of static utility methods, this constructor is intentionally public.

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    findAvailableTcpPort()
    Find an available TCP port randomly selected from the range [1024, 65535].
    static int
    findAvailableTcpPort(int minPort)
    Find an available TCP port randomly selected from the range [minPort, 65535].
    static int
    findAvailableTcpPort(int minPort, int maxPort)
    Find an available TCP port randomly selected from the range [minPort, maxPort].
    static SortedSet<Integer>
    findAvailableTcpPorts(int numRequested)
    Find the requested number of available TCP ports, each randomly selected from the range [1024, 65535].
    static SortedSet<Integer>
    findAvailableTcpPorts(int numRequested, int minPort, int maxPort)
    Find the requested number of available TCP ports, each randomly selected from the range [minPort, maxPort].
    static int
    findAvailableUdpPort()
    Find an available UDP port randomly selected from the range [1024, 65535].
    static int
    findAvailableUdpPort(int minPort)
    Find an available UDP port randomly selected from the range [minPort, 65535].
    static int
    findAvailableUdpPort(int minPort, int maxPort)
    Find an available UDP port randomly selected from the range [minPort, maxPort].
    static SortedSet<Integer>
    findAvailableUdpPorts(int numRequested)
    Find the requested number of available UDP ports, each randomly selected from the range [1024, 65535].
    static SortedSet<Integer>
    findAvailableUdpPorts(int numRequested, int minPort, int maxPort)
    Find the requested number of available UDP ports, each randomly selected from the range [minPort, maxPort].

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • PORT_RANGE_MIN

      public static final int PORT_RANGE_MIN
      The default minimum value for port ranges used when finding an available socket port.
      See Also:

    • PORT_RANGE_MAX

      public static final int PORT_RANGE_MAX
      The default maximum value for port ranges used when finding an available socket port.
      See Also:

  • Constructor Details

    • SocketUtils

      public SocketUtils()
      Although SocketUtils consists solely of static utility methods, this constructor is intentionally public.

      Rationale

      Static methods from this class may be invoked from within XML configuration files using the Spring Expression Language (SpEL) and the following syntax. 

       <bean id="bean1" ... p:port="#{T(org.springframework.util.SocketUtils).findAvailableTcpPort(12000)}" />
      If this constructor were private, you would be required to supply the fully qualified class name to SpEL's T() function for each usage. Thus, the fact that this constructor is public allows you to reduce boilerplate configuration with SpEL as can be seen in the following example. 
       <bean id="socketUtils" class="org.springframework.util.SocketUtils" />
 <bean id="bean1" ... p:port="#{socketUtils.findAvailableTcpPort(12000)}" />
 <bean id="bean2" ... p:port="#{socketUtils.findAvailableTcpPort(30000)}" />

  • Method Details

    • findAvailableTcpPort

      public static int findAvailableTcpPort()
      Find an available TCP port randomly selected from the range [1024, 65535].
      Returns:
      an available TCP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableTcpPort

      public static int findAvailableTcpPort(int minPort)
      Find an available TCP port randomly selected from the range [minPort, 65535].
      Parameters:
      minPort - the minimum port number
      Returns:
      an available TCP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableTcpPort

      public static int findAvailableTcpPort(int minPort, int maxPort)
      Find an available TCP port randomly selected from the range [minPort, maxPort].
      Parameters:
      minPort - the minimum port number
      maxPort - the maximum port number
      Returns:
      an available TCP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableTcpPorts

      public static SortedSet<Integer> findAvailableTcpPorts(int numRequested)
      Find the requested number of available TCP ports, each randomly selected from the range [1024, 65535].
      Parameters:
      numRequested - the number of available ports to find
      Returns:
      a sorted set of available TCP port numbers
      Throws:
      IllegalStateException - if the requested number of available ports could not be found

    • findAvailableTcpPorts

      public static SortedSet<Integer> findAvailableTcpPorts(int numRequested, int minPort, int maxPort)
      Find the requested number of available TCP ports, each randomly selected from the range [minPort, maxPort].
      Parameters:
      numRequested - the number of available ports to find
      minPort - the minimum port number
      maxPort - the maximum port number
      Returns:
      a sorted set of available TCP port numbers
      Throws:
      IllegalStateException - if the requested number of available ports could not be found

    • findAvailableUdpPort

      public static int findAvailableUdpPort()
      Find an available UDP port randomly selected from the range [1024, 65535].
      Returns:
      an available UDP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableUdpPort

      public static int findAvailableUdpPort(int minPort)
      Find an available UDP port randomly selected from the range [minPort, 65535].
      Parameters:
      minPort - the minimum port number
      Returns:
      an available UDP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableUdpPort

      public static int findAvailableUdpPort(int minPort, int maxPort)
      Find an available UDP port randomly selected from the range [minPort, maxPort].
      Parameters:
      minPort - the minimum port number
      maxPort - the maximum port number
      Returns:
      an available UDP port number
      Throws:
      IllegalStateException - if no available port could be found

    • findAvailableUdpPorts

      public static SortedSet<Integer> findAvailableUdpPorts(int numRequested)
      Find the requested number of available UDP ports, each randomly selected from the range [1024, 65535].
      Parameters:
      numRequested - the number of available ports to find
      Returns:
      a sorted set of available UDP port numbers
      Throws:
      IllegalStateException - if the requested number of available ports could not be found

    • findAvailableUdpPorts

      public static SortedSet<Integer> findAvailableUdpPorts(int numRequested, int minPort, int maxPort)
      Find the requested number of available UDP ports, each randomly selected from the range [minPort, maxPort].
      Parameters:
      numRequested - the number of available ports to find
      minPort - the minimum port number
      maxPort - the maximum port number
      Returns:
      a sorted set of available UDP port numbers
      Throws:
      IllegalStateException - if the requested number of available ports could not be found