public
final
class
NetworkInterface
extends Object
java.lang.Object | |
↳ | java.net.NetworkInterface |
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".
Public methods | |
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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 |
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 |
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. |
Inherited methods | |
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From
class
java.lang.Object
|
boolean equals (Object 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.
Parameters | |
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obj |
Object :
the object to compare against. |
Returns | |
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boolean |
true if the objects are the same;
false otherwise. |
See also:
NetworkInterface getByIndex (int index)
Get a network interface given its index.
Parameters | |
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index |
int :
an integer, the index of the interface |
Returns | |
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NetworkInterface |
the NetworkInterface obtained from its index, or null if
there is no interface with such an index on the system |
Throws | |
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SocketException |
if an I/O error occurs. |
IllegalArgumentException |
if index has a negative value |
See also:
NetworkInterface getByInetAddress (InetAddress addr)
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 | |
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addr |
InetAddress :
The InetAddress to search with. |
Returns | |
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NetworkInterface |
A NetworkInterface or null if there is no network interface with the specified IP address. |
Throws | |
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SocketException |
If an I/O error occurs. |
NullPointerException |
If the specified address is null. |
NetworkInterface getByName (String name)
Searches for the network interface with the specified name.
Parameters | |
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name |
String :
The name of the network interface. |
Returns | |
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NetworkInterface |
A NetworkInterface with the specified name, or null if there is no network interface with the specified name. |
Throws | |
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SocketException |
If an I/O error occurs. |
NullPointerException |
If the specified name is null. |
String getDisplayName ()
Get the display name of this network interface. A display name is a human readable String describing the network device.
Returns | |
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String |
a non-empty string representing the display name of this network interface, or null if no display name is available. |
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.
If a security manager is set, then the caller must have
the permission NetPermission
("getNetworkInformation").
Returns | |
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byte[] |
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 | |
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SocketException |
if an I/O error occurs. |
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 | |
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int |
the index of this network interface or -1 if the index is
unknown |
See also:
Enumeration<InetAddress> 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
("getNetworkInformation") permission, then all
InetAddresses are returned.
Returns | |
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Enumeration<InetAddress> |
an Enumeration object 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.
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 | |
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List<InterfaceAddress> |
a List object with all or a subset of the
InterfaceAddresss of this network interface |
int getMTU ()
Returns the Maximum Transmission Unit (MTU) of this interface.
Returns | |
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int |
the value of the MTU for that interface. |
Throws | |
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SocketException |
if an I/O error occurs. |
String getName ()
Get the name of this network interface.
Returns | |
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String |
the name of this network interface |
Enumeration<NetworkInterface> getNetworkInterfaces ()
Returns all the interfaces on this machine. Returns null if no network interfaces could be found on this machine. NOTE: can use getNetworkInterfaces()+getInetAddresses() to obtain all IP addresses for this node
Returns | |
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Enumeration<NetworkInterface> |
an Enumeration of NetworkInterfaces found on this machine |
Throws | |
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SocketException |
if an I/O error occurs. |
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.
Returns | |
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NetworkInterface |
The NetworkInterface this interface is attached to. |
Enumeration<NetworkInterface> 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 | |
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Enumeration<NetworkInterface> |
an Enumeration object with all of the subinterfaces of this network interface |
int 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
.
The general contract of hashCode
is:
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.
equals(Object)
method, then calling the hashCode
method on each of
the two objects must produce the same integer result.
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
JavaTM programming language.)
Returns | |
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int |
a hash code value for this object. |
boolean isLoopback ()
Returns whether a network interface is a loopback interface.
Returns | |
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boolean |
true if the interface is a loopback interface. |
Throws | |
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SocketException |
if an I/O error occurs. |
boolean isPointToPoint ()
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 | |
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boolean |
true if the interface is a point to point
interface. |
Throws | |
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SocketException |
if an I/O error occurs. |
boolean isUp ()
Returns whether a network interface is up and running.
Returns | |
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boolean |
true if the interface is up and running. |
Throws | |
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SocketException |
if an I/O error occurs. |
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 | |
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boolean |
true if this interface is a virtual interface. |
boolean supportsMulticast ()
Returns whether a network interface supports multicasting or not.
Returns | |
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boolean |
true if the interface supports Multicasting. |
Throws | |
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SocketException |
if an I/O error occurs. |
String 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())
Returns | |
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String |
a string representation of the object. |