# SocketImpl

public abstract class **SocketImpl** extends [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)  
implements [SocketOptions](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html) The abstract class `SocketImpl` is a common superclass
of all classes that actually implement sockets. It is used to
create both client and server sockets.


A "plain" socket implements these methods exactly as
described, without attempting to go through a firewall or proxy.

### Inherited Constant Summary

From interface [java.net.SocketOptions](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html)

|---|---|---|
| int | [IP_MULTICAST_IF](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#IP_MULTICAST_IF) | Set which outgoing interface on which to send multicast packets. |
| int | [IP_MULTICAST_IF2](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#IP_MULTICAST_IF2) | Same as above. |
| int | [IP_MULTICAST_LOOP](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#IP_MULTICAST_LOOP) | This option enables or disables local loopback of multicast datagrams. |
| int | [IP_TOS](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#IP_TOS) | This option sets the type-of-service or traffic class field in the IP header for a TCP or UDP socket. |
| int | [SO_BINDADDR](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_BINDADDR) | Fetch the local address binding of a socket (this option cannot be "set" only "gotten", since sockets are bound at creation time, and so the locally bound address cannot be changed). |
| int | [SO_BROADCAST](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_BROADCAST) | Sets SO_BROADCAST for a socket. |
| int | [SO_KEEPALIVE](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_KEEPALIVE) | When the keepalive option is set for a TCP socket and no data has been exchanged across the socket in either direction for 2 hours (NOTE: the actual value is implementation dependent), TCP automatically sends a keepalive probe to the peer. |
| int | [SO_LINGER](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_LINGER) | Specify a linger-on-close timeout. |
| int | [SO_OOBINLINE](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_OOBINLINE) | When the OOBINLINE option is set, any TCP urgent data received on the socket will be received through the socket input stream. |
| int | [SO_RCVBUF](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_RCVBUF) | Set a hint the size of the underlying buffers used by the platform for incoming network I/O. |
| int | [SO_REUSEADDR](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_REUSEADDR) | Sets SO_REUSEADDR for a socket. |
| int | [SO_SNDBUF](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_SNDBUF) | Set a hint the size of the underlying buffers used by the platform for outgoing network I/O. |
| int | [SO_TIMEOUT](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#SO_TIMEOUT) | Set a timeout on blocking Socket operations: ``` ServerSocket.accept(); SocketInputStream.read(); DatagramSocket.receive(); ``` The option must be set prior to entering a blocking operation to take effect. |
| int | [TCP_NODELAY](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#TCP_NODELAY) | Disable Nagle's algorithm for this connection. |

### Field Summary

|---|---|---|
| protected [InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) | [address](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#address) | The IP address of the remote end of this socket. |
| protected [FileDescriptor](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/FileDescriptor.html) | [fd](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#fd) | The file descriptor object for this socket. |
| protected int | [localport](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#localport) | The local port number to which this socket is connected. |
| protected int | [port](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#port) | The port number on the remote host to which this socket is connected. |

### Public Constructor Summary

|---|---|
|   | [SocketImpl](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#SocketImpl())() |

### Public Method Summary

|---|---|
| [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [toString](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#toString())() Returns the address and port of this socket as a `String`. |

### Protected Method Summary

|---|---|
| abstract void | [accept](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#accept(java.net.SocketImpl))([SocketImpl](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html) s) Accepts a connection. |
| abstract int | [available](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#available())() Returns the number of bytes that can be read from this socket without blocking. |
| abstract void | [bind](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#bind(java.net.InetAddress,%20int))([InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) host, int port) Binds this socket to the specified local IP address and port number. |
| abstract void | [close](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#close())() Closes this socket. |
| abstract void | [connect](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#connect(java.net.InetAddress,%20int))([InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) address, int port) Connects this socket to the specified port number on the specified host. |
| abstract void | [connect](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#connect(java.net.SocketAddress,%20int))([SocketAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketAddress.html) address, int timeout) Connects this socket to the specified port number on the specified host. |
| abstract void | [connect](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#connect(java.lang.String,%20int))([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) host, int port) Connects this socket to the specified port on the named host. |
| abstract void | [create](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#create(boolean))(boolean stream) Creates either a stream or a datagram socket. |
| [FileDescriptor](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/FileDescriptor.html) | [getFileDescriptor](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getFileDescriptor())() Returns the value of this socket's `fd` field. |
| [InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) | [getInetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getInetAddress())() Returns the value of this socket's `address` field. |
| abstract [InputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/InputStream.html) | [getInputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getInputStream())() Returns an input stream for this socket. |
| int | [getLocalPort](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getLocalPort())() Returns the value of this socket's `localport` field. |
| abstract [OutputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/OutputStream.html) | [getOutputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getOutputStream())() Returns an output stream for this socket. |
| int | [getPort](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#getPort())() Returns the value of this socket's `port` field. |
| abstract void | [listen](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#listen(int))(int backlog) Sets the maximum queue length for incoming connection indications (a request to connect) to the `count` argument. |
| abstract void | [sendUrgentData](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#sendUrgentData(int))(int data) Send one byte of urgent data on the socket. |
| void | [setPerformancePreferences](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#setPerformancePreferences(int,%20int,%20int))(int connectionTime, int latency, int bandwidth) Sets performance preferences for this socket. |
| void | [shutdownInput](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#shutdownInput())() Places the input stream for this socket at "end of stream". |
| void | [shutdownOutput](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#shutdownOutput())() Disables the output stream for this socket. |
| boolean | [supportsUrgentData](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#supportsUrgentData())() Returns whether or not this SocketImpl supports sending urgent data. |

### Inherited Method Summary

From class [java.lang.Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)

|---|---|
| [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) | [clone](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#clone())() Creates and returns a copy of this `Object`. |
| boolean | [equals](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#equals(java.lang.Object))([Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) obj) Compares this instance with the specified object and indicates if they are equal. |
| void | [finalize](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#finalize())() Invoked when the garbage collector has detected that this instance is no longer reachable. |
| final [Class](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html)\<?\> | [getClass](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#getClass())() Returns the unique instance of `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html` that represents this object's class. |
| int | [hashCode](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#hashCode())() Returns an integer hash code for this object. |
| final void | [notify](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notify())() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| final void | [notifyAll](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notifyAll())() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [toString](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#toString())() Returns a string containing a concise, human-readable description of this object. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long,%20int))(long timeout, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long))(long timeout) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait())() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object. |

From interface [java.net.SocketOptions](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html)

|---|---|
| abstract [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) | [getOption](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#getOption(int))(int optID) Fetch the value of an option. |
| abstract void | [setOption](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketOptions.html#setOption(int,%20java.lang.Object))(int optID, [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) value) Enable/disable the option specified by *optID*. |

## Fields

#### protected [InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html)
**address**

The IP address of the remote end of this socket.

#### protected [FileDescriptor](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/FileDescriptor.html)
**fd**

The file descriptor object for this socket.

#### protected int
**localport**

The local port number to which this socket is connected.

#### protected int
**port**

The port number on the remote host to which this socket is connected.

## Public Constructors

#### public
**SocketImpl**
()

<br />

## Public Methods

#### public [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html)
**toString**
()

Returns the address and port of this socket as a `String`.

##### Returns

- a string representation of this socket.

## Protected Methods

#### protected abstract void
**accept**
([SocketImpl](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html) s)

Accepts a connection.

##### Parameters

| s | the accepted connection. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when accepting the connection. |
|---|---|

#### protected abstract int
**available**
()

Returns the number of bytes that can be read from this socket
without blocking.

##### Returns

- the number of bytes that can be read from this socket without blocking.

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when determining the number of bytes available. |
|---|---|

#### protected abstract void
**bind**
([InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) host, int port)

Binds this socket to the specified local IP address and port number.

##### Parameters

| host | an IP address that belongs to a local interface. |
| port | the port number. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when binding this socket. |
|---|---|

#### protected abstract void
**close**
()

Closes this socket.

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when closing this socket. |
|---|---|

#### protected abstract void
**connect**
([InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html) address, int port)

Connects this socket to the specified port number on the specified host.

##### Parameters

| address | the IP address of the remote host. |
| port | the port number. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when attempting a connection. |
|---|---|

#### protected abstract void
**connect**
([SocketAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketAddress.html) address, int timeout)

Connects this socket to the specified port number on the specified host.
A timeout of zero is interpreted as an infinite timeout. The connection
will then block until established or an error occurs.

##### Parameters

| address | the Socket address of the remote host. |
| timeout | the timeout value, in milliseconds, or zero for no timeout. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when attempting a connection. |
|---|---|

#### protected abstract void
**connect**
([String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) host, int port)

Connects this socket to the specified port on the named host.

##### Parameters

| host | the name of the remote host. |
| port | the port number. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when connecting to the remote host. |
|---|---|

#### protected abstract void
**create**
(boolean stream)

Creates either a stream or a datagram socket.

##### Parameters

| stream | if `true`, create a stream socket; otherwise, create a datagram socket. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs while creating the socket. |
|---|---|

#### protected [FileDescriptor](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/FileDescriptor.html)
**getFileDescriptor**
()

Returns the value of this socket's `fd` field.

##### Returns

- the value of this socket's `fd` field.

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#fd`

#### protected [InetAddress](https://developers.google.com/j2objc/javadoc/jre/reference/java/net/InetAddress.html)
**getInetAddress**
()

Returns the value of this socket's `address` field.

##### Returns

- the value of this socket's `address` field.

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#address`

#### protected abstract [InputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/InputStream.html)
**getInputStream**
()

Returns an input stream for this socket.

##### Returns

- a stream for reading from this socket.

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when creating the input stream. |
|---|---|

#### protected int
**getLocalPort**
()

Returns the value of this socket's `localport` field.

##### Returns

- the value of this socket's `localport` field.

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#localport`

#### protected abstract [OutputStream](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/OutputStream.html)
**getOutputStream**
()

Returns an output stream for this socket.

##### Returns

- an output stream for writing to this socket.

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when creating the output stream. |
|---|---|

#### protected int
**getPort**
()

Returns the value of this socket's `port` field.

##### Returns

- the value of this socket's `port` field.

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#port`

#### protected abstract void
**listen**
(int backlog)

Sets the maximum queue length for incoming connection indications
(a request to connect) to the `count` argument. If a
connection indication arrives when the queue is full, the
connection is refused.

##### Parameters

| backlog | the maximum length of the queue. |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when creating the queue. |
|---|---|

#### protected abstract void
**sendUrgentData**
(int data)

Send one byte of urgent data on the socket.
The byte to be sent is the low eight bits of the parameter

##### Parameters

| data | The byte of data to send |
|---|---|

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if there is an error sending the data. |
|---|---|

#### protected void
**setPerformancePreferences**
(int connectionTime, int latency, int bandwidth)

Sets performance preferences for this socket.

Sockets use the TCP/IP protocol by default. Some implementations
may offer alternative protocols which have different performance
characteristics than TCP/IP. This method allows the application to
express its own preferences as to how these tradeoffs should be made
when the implementation chooses from the available protocols.

Performance preferences are described by three integers
whose values indicate the relative importance of short connection time,
low latency, and high bandwidth. The absolute values of the integers
are irrelevant; in order to choose a protocol the values are simply
compared, with larger values indicating stronger preferences. Negative
values represent a lower priority than positive values. If the
application prefers short connection time over both low latency and high
bandwidth, for example, then it could invoke this method with the values
`(1, 0, 0)`. If the application prefers high bandwidth above low
latency, and low latency above short connection time, then it could
invoke this method with the values `(0, 1, 2)`.

By default, this method does nothing, unless it is overridden in a
a sub-class.

##### Parameters

| connectionTime | An `int` expressing the relative importance of a short connection time |
| latency | An `int` expressing the relative importance of low latency |
| bandwidth | An `int` expressing the relative importance of high bandwidth |
|---|---|

#### protected void
**shutdownInput**
()

Places the input stream for this socket at "end of stream".
Any data sent to this socket is acknowledged and then
silently discarded.

If you read from a socket input stream after invoking this method on the
socket, the stream's `available` method will return 0, and its
`read` methods will return `-1` (end of stream).

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when shutting down this socket. |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#shutdownOutput()`
- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#close()`
- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#setSoLinger(boolean,%20int)`

#### protected void
**shutdownOutput**
()

Disables the output stream for this socket.
For a TCP socket, any previously written data will be sent
followed by TCP's normal connection termination sequence.

If you write to a socket output stream after invoking
shutdownOutput() on the socket, the stream will throw
an IOException.

##### Throws

| [IOException](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/IOException.html) | if an I/O error occurs when shutting down this socket. |
|---|---|

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#shutdownInput()`
- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#close()`
- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/Socket.html#setSoLinger(boolean,%20int)`

#### protected boolean
**supportsUrgentData**
()

Returns whether or not this SocketImpl supports sending
urgent data. By default, false is returned
unless the method is overridden in a sub-class

##### Returns

- true if urgent data supported

##### See Also

- `https://developers.google.com/j2objc/javadoc/jre/reference/java/net/SocketImpl.html#address`