Package org.broadinstitute.http.nio

Class HttpSeekableByteChannel

java.lang.Object

org.broadinstitute.http.nio.HttpSeekableByteChannel

All Implemented Interfaces:

Closeable, AutoCloseable, ByteChannel, Channel, ReadableByteChannel, SeekableByteChannel, WritableByteChannel

public class HttpSeekableByteChannel
extends Object
implements SeekableByteChannel

Implementation for a SeekableByteChannel for URL open as a connection.

The current implementation is thread-safe using the synchronized keyword in every method.

Field Summary

Fields

Modifier and Type	Field	Description
private InputStream	backingStream
private ReadableByteChannel	channel
private final HttpClient	client
private static final org.slf4j.Logger	LOGGER
private long	position
private final RetryHandler	retryHandler
private long	size
private static final long	SKIP_DISTANCE
private final URI	uri

Constructor Summary

Constructors

Constructor	Description
HttpSeekableByteChannel(URI uri)	create a new seekable channel with default setttings at beggining of the file
HttpSeekableByteChannel(URI uri, long position)	Create a new seekable channel with default setttins and seek to the given position
HttpSeekableByteChannel(URI uri, HttpFileSystemProviderSettings settings, long position)	Create a new seekable channel which reads from the requested URI

Method Summary

Modifier and Type	Method	Description
private void	assertChannelIsOpen()
private void	assertGoodHttpResponse(HttpResponse<?> response, boolean isRangeRequest)	Checks for the approprate http response code and throws an exception if the wrong one is found.
void	close()
private void	closeSilently()
boolean	isOpen()
private void	openChannel(long position)
long	position()
HttpSeekableByteChannel	position(long newPosition)
int	read(ByteBuffer dst)
static int	readWithoutPerturbingTheBufferIfAnErrorOccurs(ByteBuffer dst, ReadableByteChannel channel)	Performs the equivalent of a channel.read(buf) operation but in the case of an exception the state of the input buffer is not adversely impacted.
long	size()
SeekableByteChannel	truncate(long size)
int	write(ByteBuffer src)

Methods inherited from class java.lang.Object

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

Field Details

SKIP_DISTANCE

private static final long SKIP_DISTANCE

See Also:

• Constant Field Values

LOGGER

private static final org.slf4j.Logger LOGGER

uri

private final URI uri

retryHandler

private final RetryHandler retryHandler

client

private final HttpClient client

channel

private ReadableByteChannel channel

backingStream

private InputStream backingStream

position

private long position

size

private long size

Constructor Details

HttpSeekableByteChannel

public HttpSeekableByteChannel(URI uri)
                        throws IOException

create a new seekable channel with default setttings at beggining of the file

Parameters:

uri - the URI to connect to, this should not include range parameters already

Throws:

IOException - if no connection can be established

HttpSeekableByteChannel

public HttpSeekableByteChannel(URI uri,
 long position)
                        throws IOException

Create a new seekable channel with default setttins and seek to the given position

Parameters:

uri - the URI to connect to, this should not include range parameters already

position - an initial byte offset to open the file at

Throws:

IOException - if no connection can be established

HttpSeekableByteChannel

public HttpSeekableByteChannel(URI uri,
 HttpFileSystemProviderSettings settings,
 long position)
                        throws IOException

Create a new seekable channel which reads from the requested URI

Parameters:

uri - the URI to connect to, this should not include range parameters already

settings - settings to configure the connection and retry handling

position - an initial byte offset to open the file at

Throws:

IOException - if no connection can be established

Method Details

read

public int read(ByteBuffer dst)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Specified by:

read in interface SeekableByteChannel

Throws:

IOException

readWithoutPerturbingTheBufferIfAnErrorOccurs

public static int readWithoutPerturbingTheBufferIfAnErrorOccurs(ByteBuffer dst,
 ReadableByteChannel channel)
                                                         throws IOException

Performs the equivalent of a channel.read(buf) operation but in the case of an exception the state of the input buffer is not adversely impacted.

Parameters:

dst - a ByteBuffer to read into

channel - the channel to reaad from

Returns:

the number of bytes read from the channel

Throws:

IOException - if the read operation throws

assertChannelIsOpen

private void assertChannelIsOpen()
                          throws ClosedChannelException

Throws:

ClosedChannelException

write

public int write(ByteBuffer src)

Specified by:

write in interface SeekableByteChannel

Specified by:

write in interface WritableByteChannel

position

public long position()
              throws IOException

Specified by:

position in interface SeekableByteChannel

Throws:

IOException

position

public HttpSeekableByteChannel position(long newPosition)
                                 throws IOException

Specified by:

position in interface SeekableByteChannel

Throws:

IOException

size

public long size()
          throws IOException

Specified by:

size in interface SeekableByteChannel

Throws:

IOException

assertGoodHttpResponse

private void assertGoodHttpResponse(HttpResponse<?> response,
 boolean isRangeRequest)
                             throws FileNotFoundException,
UnexpectedHttpResponseException

Checks for the approprate http response code and throws an exception if the wrong one is found.

Parameters:

response - the completed HttpResponse

isRangeRequest - if this query was expecting a subrange of the file

Throws:

FileNotFoundException - on a 404

IncompatibleResponseToRangeQueryException - if it expected a subset of the file but got the whole thing or vice versa

UnexpectedHttpResponseException - if it reieves any other http response

truncate

public SeekableByteChannel truncate(long size)

Specified by:

truncate in interface SeekableByteChannel

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface Closeable

Throws:

IOException

closeSilently

private void closeSilently()

openChannel

private void openChannel(long position)
                  throws IOException

Throws:

IOException