NetworkInterface (Java Platform SE 8 ) (original) (raw)
- java.net.NetworkInterface
public final class NetworkInterface
extends Object
This class represents a Network Interface made up of a name, and a list of IP addresses assigned to this interface. It is used to identify the local interface on which a multicast group is joined. Interfaces are normally known by names such as "le0".
Since:
1.4
Method Summary
All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type Method Description boolean equals(Object obj) Compares this object against the specified object. static NetworkInterface getByIndex(int index) Get a network interface given its index. static NetworkInterface getByInetAddress(InetAddress addr) Convenience method to search for a network interface that has the specified Internet Protocol (IP) address bound to it. static NetworkInterface getByName(String name) Searches for the network interface with the specified name. String getDisplayName() Get the display name of this network interface. byte[] getHardwareAddress() Returns the hardware address (usually MAC) of the interface if it has one and if it can be accessed given the current privileges. int getIndex() Returns the index of this network interface. Enumeration<InetAddress> getInetAddresses() Convenience method to return an Enumeration with all or a subset of the InetAddresses bound to this network interface. List<InterfaceAddress> getInterfaceAddresses() Get a List of all or a subset of the InterfaceAddresses of this network interface. int getMTU() Returns the Maximum Transmission Unit (MTU) of this interface. String getName() Get the name of this network interface. static Enumeration<NetworkInterface> getNetworkInterfaces() Returns all the interfaces on this machine. NetworkInterface getParent() Returns the parent NetworkInterface of this interface if this is a subinterface, or null if it is a physical (non virtual) interface or has no parent. Enumeration<NetworkInterface> getSubInterfaces() Get an Enumeration with all the subinterfaces (also known as virtual interfaces) attached to this network interface. int hashCode() Returns a hash code value for the object. boolean isLoopback() Returns whether a network interface is a loopback interface. boolean isPointToPoint() Returns whether a network interface is a point to point interface. boolean isUp() Returns whether a network interface is up and running. boolean isVirtual() Returns whether this interface is a virtual interface (also called subinterface). boolean supportsMulticast() Returns whether a network interface supports multicasting or not. String toString() Returns a string representation of the object. * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang") `[clone](../../java/lang/Object.html#clone--), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`Method Detail
* #### getName public [String](../../java/lang/String.html "class in java.lang") getName() Get the name of this network interface. Returns: the name of this network interface * #### getInetAddresses public [Enumeration](../../java/util/Enumeration.html "interface in java.util")<[InetAddress](../../java/net/InetAddress.html "class in java.net")> getInetAddresses() Convenience method to return an Enumeration with all or a subset of the InetAddresses bound to this network interface. If there is a security manager, its `checkConnect` method is called for each InetAddress. Only InetAddresses where the `checkConnect` doesn't throw a SecurityException will be returned in the Enumeration. However, if the caller has the[NetPermission](../../java/net/NetPermission.html "class in java.net")("getNetworkInformation") permission, then all InetAddresses are returned. Returns: an Enumeration object with all or a subset of the InetAddresses bound to this network interface * #### getInterfaceAddresses public [List](../../java/util/List.html "interface in java.util")<[InterfaceAddress](../../java/net/InterfaceAddress.html "class in java.net")> getInterfaceAddresses() Get a List of all or a subset of the `InterfaceAddresses` of this network interface. If there is a security manager, its `checkConnect` method is called with the InetAddress for each InterfaceAddress. Only InterfaceAddresses where the `checkConnect` doesn't throw a SecurityException will be returned in the List. Returns: a `List` object with all or a subset of the InterfaceAddresss of this network interface Since: 1.6 * #### getSubInterfaces public [Enumeration](../../java/util/Enumeration.html "interface in java.util")<[NetworkInterface](../../java/net/NetworkInterface.html "class in java.net")> getSubInterfaces() Get an Enumeration with all the subinterfaces (also known as virtual interfaces) attached to this network interface. For instance eth0:1 will be a subinterface to eth0. Returns: an Enumeration object with all of the subinterfaces of this network interface Since: 1.6 * #### getParent public [NetworkInterface](../../java/net/NetworkInterface.html "class in java.net") getParent() Returns the parent NetworkInterface of this interface if this is a subinterface, or `null` if it is a physical (non virtual) interface or has no parent. Returns: The `NetworkInterface` this interface is attached to. Since: 1.6 * #### getIndex public int getIndex() Returns the index of this network interface. The index is an integer greater or equal to zero, or `-1` for unknown. This is a system specific value and interfaces with the same name can have different indexes on different machines. Returns: the index of this network interface or `-1` if the index is unknown Since: 1.7 See Also: [getByIndex(int)](../../java/net/NetworkInterface.html#getByIndex-int-) * #### getDisplayName public [String](../../java/lang/String.html "class in java.lang") getDisplayName() Get the display name of this network interface. A display name is a human readable String describing the network device. Returns: a non-empty string representing the display name of this network interface, or null if no display name is available. * #### getByName public static [NetworkInterface](../../java/net/NetworkInterface.html "class in java.net") getByName([String](../../java/lang/String.html "class in java.lang") name) throws [SocketException](../../java/net/SocketException.html "class in java.net") Searches for the network interface with the specified name. Parameters: `name` \- The name of the network interface. Returns: A `NetworkInterface` with the specified name, or `null` if there is no network interface with the specified name. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- If an I/O error occurs. `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- If the specified name is `null`. * #### getByIndex public static [NetworkInterface](../../java/net/NetworkInterface.html "class in java.net") getByIndex(int index) throws [SocketException](../../java/net/SocketException.html "class in java.net") Get a network interface given its index. Parameters: `index` \- an integer, the index of the interface Returns: the NetworkInterface obtained from its index, or `null` if there is no interface with such an index on the system Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. `[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if index has a negative value Since: 1.7 See Also: [getIndex()](../../java/net/NetworkInterface.html#getIndex--) * #### getByInetAddress public static [NetworkInterface](../../java/net/NetworkInterface.html "class in java.net") getByInetAddress([InetAddress](../../java/net/InetAddress.html "class in java.net") addr) throws [SocketException](../../java/net/SocketException.html "class in java.net") Convenience method to search for a network interface that has the specified Internet Protocol (IP) address bound to it. If the specified IP address is bound to multiple network interfaces it is not defined which network interface is returned. Parameters: `addr` \- The `InetAddress` to search with. Returns: A `NetworkInterface` or `null` if there is no network interface with the specified IP address. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- If an I/O error occurs. `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- If the specified address is `null`. * #### getNetworkInterfaces public static [Enumeration](../../java/util/Enumeration.html "interface in java.util")<[NetworkInterface](../../java/net/NetworkInterface.html "class in java.net")> getNetworkInterfaces() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns all the interfaces on this machine. The `Enumeration` contains at least one element, possibly representing a loopback interface that only supports communication between entities on this machine. NOTE: can use getNetworkInterfaces()+getInetAddresses() to obtain all IP addresses for this node Returns: an Enumeration of NetworkInterfaces found on this machine Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. * #### isUp public boolean isUp() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns whether a network interface is up and running. Returns: `true` if the interface is up and running. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### isLoopback public boolean isLoopback() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns whether a network interface is a loopback interface. Returns: `true` if the interface is a loopback interface. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### isPointToPoint public boolean isPointToPoint() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns whether a network interface is a point to point interface. A typical point to point interface would be a PPP connection through a modem. Returns: `true` if the interface is a point to point interface. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### supportsMulticast public boolean supportsMulticast() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns whether a network interface supports multicasting or not. Returns: `true` if the interface supports Multicasting. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### getHardwareAddress public byte[] getHardwareAddress() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns the hardware address (usually MAC) of the interface if it has one and if it can be accessed given the current privileges. If a security manager is set, then the caller must have the permission [NetPermission](../../java/net/NetPermission.html "class in java.net")("getNetworkInformation"). Returns: a byte array containing the address, or `null` if the address doesn't exist, is not accessible or a security manager is set and the caller does not have the permission NetPermission("getNetworkInformation") Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### getMTU public int getMTU() throws [SocketException](../../java/net/SocketException.html "class in java.net") Returns the Maximum Transmission Unit (MTU) of this interface. Returns: the value of the MTU for that interface. Throws: `[SocketException](../../java/net/SocketException.html "class in java.net")` \- if an I/O error occurs. Since: 1.6 * #### isVirtual public boolean isVirtual() Returns whether this interface is a virtual interface (also called subinterface). Virtual interfaces are, on some systems, interfaces created as a child of a physical interface and given different settings (like address or MTU). Usually the name of the interface will the name of the parent followed by a colon (:) and a number identifying the child since there can be several virtual interfaces attached to a single physical interface. Returns: `true` if this interface is a virtual interface. Since: 1.6 * #### equals public boolean equals([Object](../../java/lang/Object.html "class in java.lang") obj) Compares this object against the specified object. The result is `true` if and only if the argument is not `null` and it represents the same NetworkInterface as this object. Two instances of `NetworkInterface` represent the same NetworkInterface if both name and addrs are the same for both. Overrides: `[equals](../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Parameters: `obj` \- the object to compare against. Returns: `true` if the objects are the same;`false` otherwise. See Also: [InetAddress.getAddress()](../../java/net/InetAddress.html#getAddress--) * #### hashCode public int hashCode() Description copied from class: `[Object](../../java/lang/Object.html#hashCode--)` Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by[HashMap](../../java/util/HashMap.html "class in java.util"). The general contract of `hashCode` is: * Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. * If two objects are equal according to the `equals(Object)` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. * It is _not_ required that if two objects are unequal according to the [Object.equals(java.lang.Object)](../../java/lang/Object.html#equals-java.lang.Object-) method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. As much as is reasonably practical, the hashCode method defined by class `Object` does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.) Overrides: `[hashCode](../../java/lang/Object.html#hashCode--)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Returns: a hash code value for this object. See Also: [Object.equals(java.lang.Object)](../../java/lang/Object.html#equals-java.lang.Object-), [System.identityHashCode(java.lang.Object)](../../java/lang/System.html#identityHashCode-java.lang.Object-) * #### toString public [String](../../java/lang/String.html "class in java.lang") toString() Description copied from class: `[Object](../../java/lang/Object.html#toString--)` Returns a string representation of the object. In general, the`toString` method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The `toString` method for class `Object` returns a string consisting of the name of the class of which the object is an instance, the at-sign character \` `@`', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of: > getClass().getName() + '@' + Integer.toHexString(hashCode()) > Overrides: `[toString](../../java/lang/Object.html#toString--)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Returns: a string representation of the object.
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