- java.lang.Object
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- java.nio.channels.spi.AbstractInterruptibleChannel
 
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- All Implemented Interfaces:
- Closeable,- AutoCloseable,- Channel,- InterruptibleChannel
 - Direct Known Subclasses:
- FileChannel,- SelectableChannel
 
 public abstract class AbstractInterruptibleChannel extends Object implements Channel, InterruptibleChannel 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 beginandendmethods before and after, respectively, invoking an I/O operation that might block indefinitely. In order to ensure that theendmethod is always invoked, these methods should be used within atry...finallyblock:boolean completed = false; try { begin(); completed = ...; // Perform blocking I/O operation return ...; // Return result } finally { end(completed); }The completedargument to theendmethod 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 betrueif, and only if, some bytes were actually transferred into the invoker's target buffer.A concrete channel class must also implement the implCloseChannelmethod 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'sendmethod will throw the appropriate exception.This class performs the synchronization required to implement the Channelspecification. Implementations of theimplCloseChannelmethod need not synchronize against other threads that might be attempting to close the channel.- Since:
- 1.4
 
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Constructor SummaryConstructors Modifier Constructor Description protectedAbstractInterruptibleChannel()Initializes a new instance of this class.
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Method SummaryAll Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected voidbegin()Marks the beginning of an I/O operation that might block indefinitely.voidclose()Closes this channel.protected voidend(boolean completed)Marks the end of an I/O operation that might block indefinitely.protected abstract voidimplCloseChannel()Closes this channel.
 
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Method Detail- 
closepublic final void close() throws IOExceptionCloses 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 implCloseChannelmethod in order to complete the close operation.- Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Channel
- Specified by:
- closein interface- Closeable
- Specified by:
- closein interface- InterruptibleChannel
- Throws:
- IOException- If an I/O error occurs
 
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implCloseChannelprotected abstract void implCloseChannel() throws IOExceptionCloses this channel.This method is invoked by the closemethod 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
 
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beginprotected final void begin() 
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endprotected final void end(boolean completed) throws AsynchronousCloseExceptionMarks the end of an I/O operation that might block indefinitely.This method should be invoked in tandem with the beginmethod, using atry...finallyblock as shown above, in order to implement asynchronous closing and interruption for this channel.- Parameters:
- completed-- trueif, 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
 
 
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