Skip to content

Most visited

Recently visited

navigation
Added in API level 1

AbstractInterruptibleChannel

public abstract class AbstractInterruptibleChannel
extends Object implements Channel, InterruptibleChannel

java.lang.Object
   ↳ java.nio.channels.spi.AbstractInterruptibleChannel
Known Direct Subclasses
Known Indirect Subclasses


Base implementation class for interruptible channels.

This class encapsulates the low-level machinery required to implement the asynchronous closing and interruption of channels. A concrete channel class must invoke the begin and end methods before and after, respectively, invoking an I/O operation that might block indefinitely. In order to ensure that the end method is always invoked, these methods should be used within a try ... finally block:

 boolean completed = false;
 try {
     begin();
     completed = ...;    // Perform blocking I/O operation
     return ...;         // Return result
 } finally {
     end(completed);
 }

The completed argument to the end method tells whether or not the I/O operation actually completed, that is, whether it had any effect that would be visible to the invoker. In the case of an operation that reads bytes, for example, this argument should be true if, and only if, some bytes were actually transferred into the invoker's target buffer.

A concrete channel class must also implement the implCloseChannel method in such a way that if it is invoked while another thread is blocked in a native I/O operation upon the channel then that operation will immediately return, either by throwing an exception or by returning normally. If a thread is interrupted or the channel upon which it is blocked is asynchronously closed then the channel's end method will throw the appropriate exception.

This class performs the synchronization required to implement the Channel specification. Implementations of the implCloseChannel method need not synchronize against other threads that might be attempting to close the channel.

Summary

Protected constructors

AbstractInterruptibleChannel()

Initializes a new instance of this class.

Public methods

final void close()

Closes this channel.

final boolean isOpen()

Tells whether or not this channel is open.

Protected methods

final void begin()

Marks the beginning of an I/O operation that might block indefinitely.

final void end(boolean completed)

Marks the end of an I/O operation that might block indefinitely.

abstract void implCloseChannel()

Closes this channel.

Inherited methods

From class java.lang.Object
From interface java.nio.channels.Channel
From interface java.nio.channels.InterruptibleChannel
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Protected constructors

AbstractInterruptibleChannel

Added in API level 1
AbstractInterruptibleChannel ()

Initializes a new instance of this class.

Public methods

close

Added in API level 1
void close ()

Closes this channel.

If the channel has already been closed then this method returns immediately. Otherwise it marks the channel as closed and then invokes the implCloseChannel method in order to complete the close operation.

Throws
IOException If an I/O error occurs

isOpen

Added in API level 1
boolean isOpen ()

Tells whether or not this channel is open.

Returns
boolean true if, and only if, this channel is open

Protected methods

begin

Added in API level 1
void begin ()

Marks the beginning of an I/O operation that might block indefinitely.

This method should be invoked in tandem with the end method, using a try ... finally block as shown above, in order to implement asynchronous closing and interruption for this channel.

end

Added in API level 1
void end (boolean completed)

Marks the end of an I/O operation that might block indefinitely.

This method should be invoked in tandem with the begin method, using a try ... finally block as shown above, in order to implement asynchronous closing and interruption for this channel.

Parameters
completed boolean: true if, and only if, the I/O operation completed successfully, that is, had some effect that would be visible to the operation's invoker
Throws
AsynchronousCloseException If the channel was asynchronously closed
ClosedByInterruptException If the thread blocked in the I/O operation was interrupted

implCloseChannel

Added in API level 1
void implCloseChannel ()

Closes this channel.

This method is invoked by the close method in order to perform the actual work of closing the channel. This method is only invoked if the channel has not yet been closed, and it is never invoked more than once.

An implementation of this method must arrange for any other thread that is blocked in an I/O operation upon this channel to return immediately, either by throwing an exception or by returning normally.

Throws
IOException If an I/O error occurs while closing the channel
This site uses cookies to store your preferences for site-specific language and display options.

Hooray!

This class requires API level or higher

This doc is hidden because your selected API level for the documentation is . You can change the documentation API level with the selector above the left navigation.

For more information about specifying the API level your app requires, read Supporting Different Platform Versions.