java.nio.channels.spi
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. 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

Author:

Mark Reinhold, JSR-51 Expert Group

Field Summary

private static Object	lock
private static SelectorProvider	provider

Constructor Summary

protected

SelectorProvider() Initializes a new instance of this class.

Method Summary

private static boolean	loadProviderAsService()
private static boolean	loadProviderFromProperty()
abstract DatagramChannel	openDatagramChannel() 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 inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

lock

private static final Object lock

provider

private static SelectorProvider provider

Constructor Detail

SelectorProvider

protected SelectorProvider()

Initializes a new instance of this class.

Throws:

SecurityException - If a security manager has been installed and it denies RuntimePermission("selectorProvider")

Method Detail

loadProviderFromProperty

private static boolean loadProviderFromProperty()

loadProviderAsService

private static boolean loadProviderAsService()

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:

1. 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.

2. 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 directory META-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.

3. 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

openPipe

public abstract Pipe openPipe()
                       throws IOException

Opens a pipe.

Returns:

The new pipe

Throws:

IOException

openSelector

public abstract AbstractSelector openSelector()
                                       throws IOException

Opens a selector.

Returns:

The new selector

Throws:

IOException

openServerSocketChannel

public abstract ServerSocketChannel openServerSocketChannel()
                                                     throws IOException

Opens a server-socket channel.

Returns:

The new channel

Throws:

IOException

openSocketChannel

public abstract SocketChannel openSocketChannel()
                                         throws IOException

Opens a socket channel.

Returns:

The new channel

Throws:

IOException