SelectorProvider (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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Java^TM 2 Platform
Std. Ed. v1.4.1

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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

Constructor Summary

protected SelectorProvider()
          Initializes a new instance of this class.

Method Summary

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

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

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 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.
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; IOException

openPipe

public abstract Pipe openPipe()
                       throws IOException

Opens a pipe.

Returns:: The new pipe; IOException

openSelector

public abstract AbstractSelector openSelector()
                                       throws IOException

Opens a selector.

Returns:: The new selector; IOException

openServerSocketChannel

public abstract ServerSocketChannel openServerSocketChannel()
                                                     throws IOException

Opens a server-socket channel.

Returns:: The new channel; IOException

openSocketChannel

public abstract SocketChannel openSocketChannel()
                                         throws IOException

Opens a socket channel.

Returns:: The new channel; IOException