com.yahoo.jdisc.handler

Class ReadableContentChannel

java.lang.Object

com.yahoo.jdisc.handler.ReadableContentChannel

All Implemented Interfaces:

ContentChannel, Iterable<ByteBuffer>

public final class ReadableContentChannel
extends Object
implements ContentChannel, Iterable<ByteBuffer>

This class implements a ContentChannel that has a blocking read interface. Use this class if you intend to consume the content of the ContentChannel yourself. If you intend to forward the content to another ContentChannel, use BufferedContentChannel instead. If you might want to consume the content, return a BufferedContentChannel up front, and connect that to a ReadableContentChannel at the point where you decide to consume the data.

Author:

Simon Thoresen

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ReadableContentChannel.Entry
private class	ReadableContentChannel.MyIterator

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	closed
private Object	lock
private Queue<ReadableContentChannel.Entry>	queue

Constructor Summary

Constructors

Constructor and Description
ReadableContentChannel()

Method Summary

Modifier and Type	Method and Description
int	available() Returns a lower-bound estimate on the number of bytes available to be read() without blocking.
void	close(CompletionHandler handler) Closes this ContentChannel.
void	failed(Throwable t) This method calls CompletionHandler.failed(Throwable) on all pending CompletionHandlers, and blocks all future operations to this ContentChannel (i.e.
Iterator<ByteBuffer>	iterator()
ByteBuffer	read() Returns the next ByteBuffer in the internal queue.
ContentInputStream	toStream() Creates a ContentInputStream that wraps this ReadableContentChannel.
void	write(ByteBuffer buf, CompletionHandler handler) Schedules the given ByteBuffer to be written to the content corresponding to this ContentChannel.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

lock

private final Object lock

queue

private Queue<ReadableContentChannel.Entry> queue

closed

private boolean closed

Constructor Detail

ReadableContentChannel

public ReadableContentChannel()

Method Detail

write

public void write(ByteBuffer buf,
                  CompletionHandler handler)

Description copied from interface: ContentChannel

Schedules the given ByteBuffer to be written to the content corresponding to this ContentChannel. This call transfers ownership of the given ByteBuffer to this ContentChannel, i.e. no further calls can be made to the buffer. The execution of writes happen in the same order as this method was invoked.

Specified by:

write in interface ContentChannel

Parameters:

buf - The ByteBuffer to schedule for write. No further calls can be made to this buffer.

handler - The CompletionHandler to call after the write has been executed.

close

public void close(CompletionHandler handler)

Description copied from interface: ContentChannel

Closes this ContentChannel. After a channel is closed, any further attempt to invoke ContentChannel.write(ByteBuffer, CompletionHandler) upon it will cause an IllegalStateException to be thrown. If this channel is already closed then invoking this method has no effect, but CompletionHandler.completed() will still be called. Notice that you MUST call this method, regardless of any exceptions that might have occurred while writing to this ContentChannel. Failure to do so will prevent the Container from ever shutting down.

Specified by:

close in interface ContentChannel

Parameters:

handler - The CompletionHandler to call after the close has been executed.

iterator

public Iterator<ByteBuffer> iterator()

Specified by:

iterator in interface Iterable<ByteBuffer>

available

public int available()

Returns a lower-bound estimate on the number of bytes available to be read() without blocking. If the returned number is larger than zero, the next call to read() is guaranteed to not block.

Returns:

The number of bytes available to be read without blocking.

read

public ByteBuffer read()

Returns the next ByteBuffer in the internal queue. Before returning, this method calls CompletionHandler.completed() on the CompletionHandler that was submitted along with the ByteBuffer. If there are no ByteBuffers in the queue, this method waits indefinitely for either write(ByteBuffer, CompletionHandler) or close(CompletionHandler) to be called. Once closed and the internal queue drained, this method returns null.

Returns:

The next ByteBuffer in queue, or null if this ReadableContentChannel is closed.

Throws:

IllegalStateException - If the current thread is interrupted while waiting.

failed

public void failed(Throwable t)

This method calls CompletionHandler.failed(Throwable) on all pending CompletionHandlers, and blocks all future operations to this ContentChannel (i.e. calls to write(ByteBuffer, CompletionHandler) and close(CompletionHandler) throw IllegalStateExceptions).

This method will also notify any thread waiting in read().

Parameters:

t - The Throwable to pass to all pending CompletionHandlers.

Throws:

IllegalStateException - If this method is called more than once.

toStream

public ContentInputStream toStream()

Creates a ContentInputStream that wraps this ReadableContentChannel.

Returns:

The new ContentInputStream that wraps this.