Class SelectorProvider
- java.lang.Object
-
- java.nio.channels.spi.SelectorProvider
public abstract class SelectorProvider extends Object
Service-provider class for selectors and selectable channels.
A selector provider is a concrete subclass of this class that has a zero-argument constructor and implements the abstract methods specified below. A given invocation of the Java virtual machine maintains a single system-wide default provider instance, which is returned by the provider
method. The first invocation of that method will locate the default provider as specified below.
The system-wide default provider is used by the static open
methods of the DatagramChannel
, Pipe
, Selector
, ServerSocketChannel
, and SocketChannel
classes. It is also used by the System.inheritedChannel()
method. A program may make use of a provider other than the default provider by instantiating that provider and then directly invoking the open
methods defined in this class.
All of the methods in this class are safe for use by multiple concurrent threads.
- Since:
- 1.4
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | SelectorProvider() | Initializes a new instance of this class. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
Channel | inheritedChannel() | Returns the channel inherited from the entity that created this Java virtual machine. |
abstract DatagramChannel | openDatagramChannel() | Opens a datagram channel. |
abstract DatagramChannel | openDatagramChannel(ProtocolFamily family) | Opens a datagram channel. |
abstract Pipe | openPipe() | Opens a pipe. |
abstract AbstractSelector | openSelector() | Opens a selector. |
abstract ServerSocketChannel | openServerSocketChannel() | Opens a server-socket channel. |
abstract SocketChannel | openSocketChannel() | Opens a socket channel. |
static SelectorProvider | provider() | Returns the system-wide default selector provider for this invocation of the Java virtual machine. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
SelectorProvider
protected SelectorProvider()
Initializes a new instance of this class.
- Throws:
-
SecurityException
- If a security manager has been installed and it deniesRuntimePermission
("selectorProvider")
Method Detail
provider
public static SelectorProvider provider()
Returns the system-wide default selector provider for this invocation of the Java virtual machine.
The first invocation of this method locates the default provider object as follows:
If the system property
java.nio.channels.spi.SelectorProvider
is defined then it is taken to be the fully-qualified name of a concrete provider class. The class is loaded and instantiated; if this process fails then an unspecified error is thrown.If a provider class has been installed in a jar file that is visible to the system class loader, and that jar file contains a provider-configuration file named
java.nio.channels.spi.SelectorProvider
in the resource directoryMETA-INF/services
, then the first class name specified in that file is taken. The class is loaded and instantiated; if this process fails then an unspecified error is thrown.Finally, if no provider has been specified by any of the above means then the system-default provider class is instantiated and the result is returned.
Subsequent invocations of this method return the provider that was returned by the first invocation.
- Returns:
- The system-wide default selector provider
openDatagramChannel
public abstract DatagramChannel openDatagramChannel() throws IOException
Opens a datagram channel.
- Returns:
- The new channel
- Throws:
-
IOException
- If an I/O error occurs
openDatagramChannel
public abstract DatagramChannel openDatagramChannel(ProtocolFamily family) throws IOException
Opens a datagram channel.
- Parameters:
-
family
- The protocol family - Returns:
- A new datagram channel
- Throws:
-
UnsupportedOperationException
- If the specified protocol family is not supported -
IOException
- If an I/O error occurs - Since:
- 1.7
openPipe
public abstract Pipe openPipe() throws IOException
Opens a pipe.
- Returns:
- The new pipe
- Throws:
-
IOException
- If an I/O error occurs
openSelector
public abstract AbstractSelector openSelector() throws IOException
Opens a selector.
- Returns:
- The new selector
- Throws:
-
IOException
- If an I/O error occurs
openServerSocketChannel
public abstract ServerSocketChannel openServerSocketChannel() throws IOException
Opens a server-socket channel.
- Returns:
- The new channel
- Throws:
-
IOException
- If an I/O error occurs
openSocketChannel
public abstract SocketChannel openSocketChannel() throws IOException
Opens a socket channel.
- Returns:
- The new channel
- Throws:
-
IOException
- If an I/O error occurs
inheritedChannel
public Channel inheritedChannel() throws IOException
Returns the channel inherited from the entity that created this Java virtual machine.
On many operating systems a process, such as a Java virtual machine, can be started in a manner that allows the process to inherit a channel from the entity that created the process. The manner in which this is done is system dependent, as are the possible entities to which the channel may be connected. For example, on UNIX systems, the Internet services daemon (inetd) is used to start programs to service requests when a request arrives on an associated network port. In this example, the process that is started, inherits a channel representing a network socket.
In cases where the inherited channel represents a network socket then the Channel
type returned by this method is determined as follows:
If the inherited channel represents a stream-oriented connected socket then a
SocketChannel
is returned. The socket channel is, at least initially, in blocking mode, bound to a socket address, and connected to a peer.If the inherited channel represents a stream-oriented listening socket then a
ServerSocketChannel
is returned. The server-socket channel is, at least initially, in blocking mode, and bound to a socket address.If the inherited channel is a datagram-oriented socket then a
DatagramChannel
is returned. The datagram channel is, at least initially, in blocking mode, and bound to a socket address.
In addition to the network-oriented channels described, this method may return other kinds of channels in the future.
The first invocation of this method creates the channel that is returned. Subsequent invocations of this method return the same channel.
- Returns:
- The inherited channel, if any, otherwise
null
. - Throws:
-
IOException
- If an I/O error occurs -
SecurityException
- If a security manager has been installed and it deniesRuntimePermission
("inheritedChannel")
- Since:
- 1.5