JDK8/Java8源码在线阅读
/*
* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.net;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import sun.security.action.*;
import java.security.AccessController;
/**
* 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
*/
public final class NetworkInterface {
private String name;
private String displayName;
private int index;
private InetAddress addrs[];
private InterfaceAddress bindings[];
private NetworkInterface childs[];
private NetworkInterface parent = null;
private boolean virtual = false;
private static final NetworkInterface defaultInterface;
private static final int defaultIndex; /* index of defaultInterface */
static {
AccessController.doPrivileged(
new java.security.PrivilegedAction<Void>() {
public Void run() {
System.loadLibrary("net");
return null;
}
});
init();
defaultInterface = DefaultInterface.getDefault();
if (defaultInterface != null) {
defaultIndex = defaultInterface.getIndex();
} else {
defaultIndex = 0;
}
}
/**
* Returns an NetworkInterface object with index set to 0 and name to null.
* Setting such an interface on a MulticastSocket will cause the
* kernel to choose one interface for sending multicast packets.
*
*/
NetworkInterface() {
}
NetworkInterface(String name, int index, InetAddress[] addrs) {
this.name = name;
this.index = index;
this.addrs = addrs;
}
/**
* Get the name of this network interface.
*
* @return the name of this network interface
*/
public String getName() {
return name;
}
/**
* Convenience method to return an Enumeration with all or a
* subset of the InetAddresses bound to this network interface.
* <p>
* If there is a security manager, its {@code checkConnect}
* method is called for each InetAddress. Only InetAddresses where
* the {@code checkConnect} doesn't throw a SecurityException
* will be returned in the Enumeration. However, if the caller has the
* {@link NetPermission}("getNetworkInformation") permission, then all
* InetAddresses are returned.
* @return an Enumeration object with all or a subset of the InetAddresses
* bound to this network interface
*/
public Enumeration<InetAddress> getInetAddresses() {
class checkedAddresses implements Enumeration<InetAddress> {
private int i=0, count=0;
private InetAddress local_addrs[];
checkedAddresses() {
local_addrs = new InetAddress[addrs.length];
boolean trusted = true;
SecurityManager sec = System.getSecurityManager();
if (sec != null) {
try {
sec.checkPermission(new NetPermission("getNetworkInformation"));
} catch (SecurityException e) {
trusted = false;
}
}
for (int j=0; j<addrs.length; j++) {
try {
if (sec != null && !trusted) {
sec.checkConnect(addrs[j].getHostAddress(), -1);
}
local_addrs[count++] = addrs[j];
} catch (SecurityException e) { }
}
}
public InetAddress nextElement() {
if (i < count) {
return local_addrs[i++];
} else {
throw new NoSuchElementException();
}
}
public boolean hasMoreElements() {
return (i < count);
}
}
return new checkedAddresses();
}
/**
* Get a List of all or a subset of the {@code InterfaceAddresses}
* of this network interface.
* <p>
* If there is a security manager, its {@code checkConnect}
* method is called with the InetAddress for each InterfaceAddress.
* Only InterfaceAddresses where the {@code checkConnect} doesn't throw
* a SecurityException will be returned in the List.
*
* @return a {@code List} object with all or a subset of the
* InterfaceAddresss of this network interface
* @since 1.6
*/
public java.util.List<InterfaceAddress> getInterfaceAddresses() {
java.util.List<InterfaceAddress> lst = new java.util.ArrayList<InterfaceAddress>(1);
SecurityManager sec = System.getSecurityManager();
for (int j=0; j<bindings.length; j++) {
try {
if (sec != null) {
sec.checkConnect(bindings[j].getAddress().getHostAddress(), -1);
}
lst.add(bindings[j]);
} catch (SecurityException e) { }
}
return lst;
}
/**
* Get an Enumeration with all the subinterfaces (also known as virtual
* interfaces) attached to this network interface.
* <p>
* For instance eth0:1 will be a subinterface to eth0.
*
* @return an Enumeration object with all of the subinterfaces
* of this network interface
* @since 1.6
*/
public Enumeration<NetworkInterface> getSubInterfaces() {
class subIFs implements Enumeration<NetworkInterface> {
private int i=0;
subIFs() {
}
public NetworkInterface nextElement() {
if (i < childs.length) {
return childs[i++];
} else {
throw new NoSuchElementException();
}
}
public boolean hasMoreElements() {
return (i < childs.length);
}
}
return new subIFs();
}
/**
* Returns the parent NetworkInterface of this interface if this is
* a subinterface, or {@code null} if it is a physical
* (non virtual) interface or has no parent.
*
* @return The {@code NetworkInterface} this interface is attached to.
* @since 1.6
*/
public NetworkInterface getParent() {
return parent;
}
/**
* Returns the index of this network interface. The index is an integer greater
* or equal to zero, or {@code -1} for unknown. This is a system specific value
* and interfaces with the same name can have different indexes on different
* machines.
*
* @return the index of this network interface or {@code -1} if the index is
* unknown
* @see #getByIndex(int)
* @since 1.7
*/
public int getIndex() {
return index;
}
/**
* Get the display name of this network interface.
* A display name is a human readable String describing the network
* device.
*
* @return a non-empty string representing the display name of this network
* interface, or null if no display name is available.
*/
public String getDisplayName() {
/* strict TCK conformance */
return "".equals(displayName) ? null : displayName;
}
/**
* Searches for the network interface with the specified name.
*
* @param name
* The name of the network interface.
*
* @return A {@code NetworkInterface} with the specified name,
* or {@code null} if there is no network interface
* with the specified name.
*
* @throws SocketException
* If an I/O error occurs.
*
* @throws NullPointerException
* If the specified name is {@code null}.
*/
public static NetworkInterface getByName(String name) throws SocketException {
if (name == null)
throw new NullPointerException();
return getByName0(name);
}
/**
* Get a network interface given its index.
*
* @param index an integer, the index of the interface
* @return the NetworkInterface obtained from its index, or {@code null} if
* there is no interface with such an index on the system
* @throws SocketException if an I/O error occurs.
* @throws IllegalArgumentException if index has a negative value
* @see #getIndex()
* @since 1.7
*/
public static NetworkInterface getByIndex(int index) throws SocketException {
if (index < 0)
throw new IllegalArgumentException("Interface index can't be negative");
return getByIndex0(index);
}
/**
* Convenience method to search for a network interface that
* has the specified Internet Protocol (IP) address bound to
* it.
* <p>
* If the specified IP address is bound to multiple network
* interfaces it is not defined which network interface is
* returned.
*
* @param addr
* The {@code InetAddress} to search with.
*
* @return A {@code NetworkInterface}
* or {@code null} if there is no network interface
* with the specified IP address.
*
* @throws SocketException
* If an I/O error occurs.
*
* @throws NullPointerException
* If the specified address is {@code null}.
*/
public static NetworkInterface getByInetAddress(InetAddress addr) throws SocketException {
if (addr == null) {
throw new NullPointerException();
}
if (!(addr instanceof Inet4Address || addr instanceof Inet6Address)) {
throw new IllegalArgumentException ("invalid address type");
}
return getByInetAddress0(addr);
}
/**
* Returns all the interfaces on this machine. The {@code 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
*
* @return an Enumeration of NetworkInterfaces found on this machine
* @exception SocketException if an I/O error occurs.
*/
public static Enumeration<NetworkInterface> getNetworkInterfaces()
throws SocketException {
final NetworkInterface[] netifs = getAll();
// specified to return null if no network interfaces
if (netifs == null)
return null;
return new Enumeration<NetworkInterface>() {
private int i = 0;
public NetworkInterface nextElement() {
if (netifs != null && i < netifs.length) {
NetworkInterface netif = netifs[i++];
return netif;
} else {
throw new NoSuchElementException();
}
}
public boolean hasMoreElements() {
return (netifs != null && i < netifs.length);
}
};
}
private native static NetworkInterface[] getAll()
throws SocketException;
private native static NetworkInterface getByName0(String name)
throws SocketException;
private native static NetworkInterface getByIndex0(int index)
throws SocketException;
private native static NetworkInterface getByInetAddress0(InetAddress addr)
throws SocketException;
/**
* Returns whether a network interface is up and running.
*
* @return {@code true} if the interface is up and running.
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isUp() throws SocketException {
return isUp0(name, index);
}
/**
* Returns whether a network interface is a loopback interface.
*
* @return {@code true} if the interface is a loopback interface.
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isLoopback() throws SocketException {
return isLoopback0(name, index);
}
/**
* 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.
*
* @return {@code true} if the interface is a point to point
* interface.
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean isPointToPoint() throws SocketException {
return isP2P0(name, index);
}
/**
* Returns whether a network interface supports multicasting or not.
*
* @return {@code true} if the interface supports Multicasting.
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public boolean supportsMulticast() throws SocketException {
return supportsMulticast0(name, index);
}
/**
* 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 {@link NetPermission}("getNetworkInformation").
*
* @return a byte array containing the address, or {@code 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")
*
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public byte[] getHardwareAddress() throws SocketException {
SecurityManager sec = System.getSecurityManager();
if (sec != null) {
try {
sec.checkPermission(new NetPermission("getNetworkInformation"));
} catch (SecurityException e) {
if (!getInetAddresses().hasMoreElements()) {
// don't have connect permission to any local address
return null;
}
}
}
for (InetAddress addr : addrs) {
if (addr instanceof Inet4Address) {
return getMacAddr0(((Inet4Address)addr).getAddress(), name, index);
}
}
return getMacAddr0(null, name, index);
}
/**
* Returns the Maximum Transmission Unit (MTU) of this interface.
*
* @return the value of the MTU for that interface.
* @exception SocketException if an I/O error occurs.
* @since 1.6
*/
public int getMTU() throws SocketException {
return getMTU0(name, index);
}
/**
* 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.
*
* @return {@code true} if this interface is a virtual interface.
* @since 1.6
*/
public boolean isVirtual() {
return virtual;
}
private native static boolean isUp0(String name, int ind) throws SocketException;
private native static boolean isLoopback0(String name, int ind) throws SocketException;
private native static boolean supportsMulticast0(String name, int ind) throws SocketException;
private native static boolean isP2P0(String name, int ind) throws SocketException;
private native static byte[] getMacAddr0(byte[] inAddr, String name, int ind) throws SocketException;
private native static int getMTU0(String name, int ind) throws SocketException;
/**
* Compares this object against the specified object.
* The result is {@code true} if and only if the argument is
* not {@code null} and it represents the same NetworkInterface
* as this object.
* <p>
* Two instances of {@code NetworkInterface} represent the same
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java