/*
 * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 */
package java.net;

import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.ObjectStreamField;

/**
 *
 * This class implements an IP Socket Address (IP address + port number)
 * It can also be a pair (hostname + port number), in which case an attempt
 * will be made to resolve the hostname. If resolution fails then the address
 * is said to be <I>unresolved</I> but can still be used on some circumstances
 * like connecting through a proxy.
 * <p>
 * It provides an immutable object used by sockets for binding, connecting, or
 * as returned values.
 * <p>
 * The <i>wildcard</i> is a special local IP address. It usually means "any"
 * and can only be used for {@code bind} operations.
 *
 * @see java.net.Socket
 * @see java.net.ServerSocket
 * @since 1.4
 */
public class InetSocketAddress
 extends SocketAddress
{
 // Private implementation class pointed to by all public methods.
 private static class InetSocketAddressHolder {
 // The hostname of the Socket Address
 private String hostname;
 // The IP address of the Socket Address
 private InetAddress addr;
 // The port number of the Socket Address
 private int port;

 private InetSocketAddressHolder(String hostname, InetAddress addr, int port) {
 this.hostname = hostname;
 this.addr = addr;
 this.port = port;
 }

 private int getPort() {
 return port;
 }

 private InetAddress getAddress() {
 return addr;
 }

 private String getHostName() {
 if (hostname != null)
 return hostname;
 if (addr != null)
 return addr.getHostName();
 return null;
 }

 private String getHostString() {
 if (hostname != null)
 return hostname;
 if (addr != null) {
 if (addr.holder().getHostName() != null)
 return addr.holder().getHostName();
 else
 return addr.getHostAddress();
 }
 return null;
 }

 private boolean isUnresolved() {
 return addr == null;
 }

 @Override
 public String toString() {
 if (isUnresolved()) {
 return hostname + ":" + port;
 } else {
 return addr.toString() + ":" + port;
 }
 }

 @Override
 public final boolean equals(Object obj) {
 if (obj == null || !(obj instanceof InetSocketAddressHolder))
 return false;
 InetSocketAddressHolder that = (InetSocketAddressHolder)obj;
 boolean sameIP;
 if (addr != null)
 sameIP = addr.equals(that.addr);
 else if (hostname != null)
 sameIP = (that.addr == null) &&
 hostname.equalsIgnoreCase(that.hostname);
 else
 sameIP = (that.addr == null) && (that.hostname == null);
 return sameIP && (port == that.port);
 }

 @Override
 public final int hashCode() {
 if (addr != null)
 return addr.hashCode() + port;
 if (hostname != null)
 return hostname.toLowerCase().hashCode() + port;
 return port;
 }
 }

 private final transient InetSocketAddressHolder holder;

 private static final long serialVersionUID = 5076001401234631237L;

 private static int checkPort(int port) {
 if (port < 0 || port > 0xFFFF)
 throw new IllegalArgumentException("port out of range:" + port);
 return port;
 }

 private static String checkHost(String hostname) {
 if (hostname == null)
 throw new IllegalArgumentException("hostname can't be null");
 return hostname;
 }

 /**
 * Creates a socket address where the IP address is the wildcard address
 * and the port number a specified value.
 * <p>
 * A valid port value is between 0 and 65535.
 * A port number of {@code zero} will let the system pick up an
 * ephemeral port in a {@code bind} operation.
 *
 * @param port The port number
 * @throws IllegalArgumentException if the port parameter is outside the specified
 * range of valid port values.
 */
 public InetSocketAddress(int port) {
 this(InetAddress.anyLocalAddress(), port);
 }

 /**
 *
 * Creates a socket address from an IP address and a port number.
 * <p>
 * A valid port value is between 0 and 65535.
 * A port number of {@code zero} will let the system pick up an
 * ephemeral port in a {@code bind} operation.
 * <P>
 * A {@code null} address will assign the <i>wildcard</i> address.
 *
 * @param addr The IP address
 * @param port The port number
 * @throws IllegalArgumentException if the port parameter is outside the specified
 * range of valid port values.
 */
 public InetSocketAddress(InetAddress addr, int port) {
 holder = new InetSocketAddressHolder(
 null,
 addr == null ? InetAddress.anyLocalAddress() : addr,
 checkPort(port));
 }

 /**
 *
 * Creates a socket address from a hostname and a port number.
 * <p>
 * An attempt will be made to resolve the hostname into an InetAddress.
 * If that attempt fails, the address will be flagged as <I>unresolved</I>.
 * <p>
 * If there is a security manager, its {@code checkConnect} method
 * is called with the host name as its argument to check the permission
 * to resolve it. This could result in a SecurityException.
 * <P>
 * A valid port value is between 0 and 65535.
 * A port number of {@code zero} will let the system pick up an
 * ephemeral port in a {@code bind} operation.
 *
 * @param hostname the Host name
 * @param port The port number
 * @throws IllegalArgumentException if the port parameter is outside the range
 * of valid port values, or if the hostname parameter is {@code null}.
 * @throws SecurityException if a security manager is present and
 * permission to resolve the host name is
 * denied.
 * @see #isUnresolved()
 */
 public InetSocketAddress(String hostname, int port) {
 checkHost(hostname);
 InetAddress addr = null;
 String host = null;
 try {
 addr = InetAddress.getByName(hostname);
 } catch(UnknownHostException e) {
 host = hostname;
 }
 holder = new InetSocketAddressHolder(host, addr, checkPort(port));
 }

 // private constructor for creating unresolved instances
 private InetSocketAddress(int port, String hostname) {
 holder = new InetSocketAddressHolder(hostname, null, port);
 }

 /**
 *
 * Creates an unresolved socket address from a hostname and a port number.
 * <p>
 * No attempt will be made to resolve the hostname into an InetAddress.
 * The address will be flagged as <I>unresolved</I>.
 * <p>
 * A valid port value is between 0 and 65535.
 * A port number of {@code zero} will let the system pick up an
 * ephemeral port in a {@code bind} operation.
 *
 * @param host the Host name
 * @param port The port number
 * @throws IllegalArgumentException if the port parameter is outside
 * the range of valid port values, or if the hostname
 * parameter is {@code null}.
 * @see #isUnresolved()
 * @return an {@code InetSocketAddress} representing the unresolved
 * socket address
 * @since 1.5
 */
 public static InetSocketAddress createUnresolved(String host, int port) {
 return new InetSocketAddress(checkPort(port), checkHost(host));
 }

 /**
 * @serialField hostname String
 * @serialField addr InetAddress
 * @serialField port int
 */
 private static final ObjectStreamField[] serialPersistentFields = {
 new ObjectStreamField("hostname", String.class),
 new ObjectStreamField("addr", InetAddress.class),
 new ObjectStreamField("port", int.class)};

 private void writeObject(ObjectOutputStream out)
 throws IOException
 {
 // Don't call defaultWriteObject()
 ObjectOutputStream.PutField pfields = out.putFields();
 pfields.put("hostname", holder.hostname);
 pfields.put("addr", holder.addr);
 pfields.put("port", holder.port);
 out.writeFields();
 }

 private void readObject(ObjectInputStream in)
 throws IOException, ClassNotFoundException
 {
 // Don't call defaultReadObject()
 ObjectInputStream.GetField oisFields = in.readFields();
 final String oisHostname = (String)oisFields.get("hostname", null);
 final InetAddress oisAddr = (InetAddress)oisFields.get("addr", null);
 final int oisPort = oisFields.get("port", -1);

 // Check that our invariants are satisfied
 checkPort(oisPort);
 if (oisHostname == null && oisAddr == null)
 throw new InvalidObjectException("hostname and addr " +
 "can't both be null");

 InetSocketAddressHolder h = new InetSocketAddressHolder(oisHostname,
 oisAddr,
 oisPort);
 UNSAFE.putObject(this, FIELDS_OFFSET, h);
 }

 private void readObjectNoData()
 throws ObjectStreamException
 {
 throw new InvalidObjectException("Stream data required");
 }

 private static final jdk.internal.misc.Unsafe UNSAFE
 = jdk.internal.misc.Unsafe.getUnsafe();
 private static final long FIELDS_OFFSET
 = UNSAFE.objectFieldOffset(InetSocketAddress.class, "holder");

 /**
 * Gets the port number.
 *
 * @return the port number.
 */
 public final int getPort() {
 return holder.getPort();
 }

 /**
 * Gets the {@code InetAddress}.
 *
 * @return the InetAddress or {@code null} if it is unresolved.
 */
 public final InetAddress getAddress() {
 return holder.getAddress();
 }

 /**
 * Gets the {@code hostname}.
 * Note: This method may trigger a name service reverse lookup if the
 * address was created with a literal IP address.
 *
 * @return the hostname part of the address.
 */
 public final String getHostName() {
 return holder.getHostName();
 }

 /**
 * Returns the hostname, or the String form of the address if it
 * doesn't have a hostname (it was created using a literal).
 * This has the benefit of <b>not</b> attempting a reverse lookup.
 *
 * @return the hostname, or String representation of the address.
 * @since 1.7
 */
 public final String getHostString() {
 return holder.getHostString();
 }

 /**
 * Checks whether the address has been resolved or not.
 *
 * @return {@code true} if the hostname couldn't be resolved into
 * an {@code InetAddress}.
 */
 public final boolean isUnresolved() {
 return holder.isUnresolved();
 }

 /**
 * Constructs a string representation of this InetSocketAddress.
 * This String is constructed by calling toString() on the InetAddress
 * and concatenating the port number (with a colon). If the address
 * is unresolved then the part before the colon will only contain the hostname.
 *
 * @return a string representation of this object.
 */
 @Override
 public String toString() {
 return holder.toString();
 }

 /**
 * 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 address as
 * this object.
 * <p>
 * Two instances of {@code InetSocketAddress} represent the same
 * address if both the InetAddresses (or hostnames if it is unresolved) and port
 * numbers are equal.
 * If both addresses are unresolved, then the hostname and the port number
 * are compared.
 *
 * Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are
 * considered equal.
 *
 * @param obj the object to compare against.
 * @return {@code true} if the objects are the same;
 * {@code false} otherwise.
 * @see java.net.InetAddress#equals(java.lang.Object)
 */
 @Override
 public final boolean equals(Object obj) {
 if (obj == null || !(obj instanceof InetSocketAddress))
 return false;
 return holder.equals(((InetSocketAddress) obj).holder);
 }

 /**
 * Returns a hashcode for this socket address.
 *
 * @return a hash code value for this socket address.
 */
 @Override
 public final int hashCode() {
 return holder.hashCode();
 }
}