gr.uoa.di.madgik.grs.proxy.http

Class HTTPReaderProxy

java.lang.Object

gr.uoa.di.madgik.grs.proxy.http.HTTPReaderProxy

All Implemented Interfaces:

IProxy, IReaderProxy

Direct Known Subclasses:

HTTPStoreReaderProxy

public class HTTPReaderProxy
extends Object
implements IReaderProxy

This proxy is an implementation of the IReaderProxy interface available to be used by readers that want to access an IBuffer made available by a writer that is not necessarily collocated in the same JVM as they are. This proxy enables access to a local or remote host through an HTTP connection.

Author:

Alex Antoniadis

Nested Class Summary

Nested classes/interfaces inherited from interface gr.uoa.di.madgik.grs.proxy.IProxy

IProxy.ProxyType

Field Summary

Fields inherited from interface gr.uoa.di.madgik.grs.proxy.IProxy

ProxyScheme, ProxyStoreScheme

Constructor Summary

Constructors

Constructor and Description
HTTPReaderProxy()

Method Summary

Methods

Modifier and Type	Method and Description
void	fromLocator(URI locator) Populates an instance of the IReaderProxy implementer with the information provided through the specific locator URI
IBuffer	getBuffer() After the proxy has been initialized, through this method, the IBuffer that can be used by the reader to access the writer side IBuffer can be retrieved
String	getHostname() Retrieves the hostname where the HTTPWriterProxy is located and is serving the consumed IBuffer
int	getPort() Retrieves the port that the HTTPWriterProxy is using to serve the consumed IBuffer
static boolean	isOfType(URI locator) Checks if the provided URI is of a type that can be managed by an instance of this class.
void	overrideBufferCapacity(int capacity) After the proxy has been initialized, this method can be used to provide a hint to the IReaderProxy to use a capacity different than that of the producer's buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

HTTPReaderProxy

public HTTPReaderProxy()

Method Detail

getHostname

public String getHostname()

Retrieves the hostname where the HTTPWriterProxy is located and is serving the consumed IBuffer

Returns:

the hostname

getPort

public int getPort()

Retrieves the port that the HTTPWriterProxy is using to serve the consumed IBuffer

Returns:

the port

fromLocator

public void fromLocator(URI locator)
                 throws GRS2ProxyInvalidOperationException,
                        GRS2ProxyInvalidArgumentException

Populates an instance of the IReaderProxy implementer with the information provided through the specific locator URI

This method parses the provided URI to retrieve the needed information. An example of the URI this proxy can manage is grs2-proxy://foo.bar.gr:53361?key=272b934d-e796-4c30-944c-44ec2aec7eb7#HTTP

Specified by:

fromLocator in interface IReaderProxy

Throws:

GRS2ProxyInvalidOperationException - if the proxy has already been initialized

GRS2ProxyInvalidArgumentException - if the provided locator is null or empty, or the parsed information is not valid

See Also:

IReaderProxy.fromLocator(java.net.URI)

overrideBufferCapacity

public void overrideBufferCapacity(int capacity)
                            throws GRS2ProxyInvalidOperationException

After the proxy has been initialized, this method can be used to provide a hint to the IReaderProxy to use a capacity different than that of the producer's buffer. Whether or not this hint is taken into account depends on the IReaderProxy implementation. For example, it is highly unlikely that it will be honored in cases when both the producer and the consumer run into the same address space. Instructs the HTTPReaderMirror that will be initialized in a subsequent operation to override its buffer capacity

Specified by:

overrideBufferCapacity in interface IReaderProxy

Throws:

GRS2ProxyInvalidOperationException - if the operation is performed after buffer initialization

See Also:

IReaderProxy.overrideBufferCapacity(int)

getBuffer

public IBuffer getBuffer()
                  throws GRS2ProxyInvalidOperationException

After the proxy has been initialized, through this method, the IBuffer that can be used by the reader to access the writer side IBuffer can be retrieved

Initializes a HTTPReaderMirror to handle the reader side mirroring procedure. The mirror is set with the information available to the proxy, using the HTTPReaderMirror.setKey(String), HTTPReaderMirror.setPort(int) and HTTPReaderMirror.setHostname(String) and then the HTTPReaderMirror.handle() method is invoked. The proxy waits for the mirroring procedure to be initialized blocking using HTTPReaderMirror.waitInitialization() and if there was any error during the initialization procedure, it is retrieved and thrown using HTTPReaderMirror.getInitializationError(). After this procedure is completed, the mirroring procedure continues in the HTTPReaderMirror thread of execution. The returned IBuffer is the one available though HTTPReaderMirror.getBuffer() and is populated from HTTPReaderMirror

Specified by:

getBuffer in interface IReaderProxy

Returns:

The IBuffer that is serving the reader

Throws:

GRS2ProxyInvalidOperationException - if the provided locator that populated this instance has not set the needed parameters

See Also:

IReaderProxy.getBuffer()

isOfType

public static boolean isOfType(URI locator)

Checks if the provided URI is of a type that can be managed by an instance of this class. It bases its checks on the URI scheme and the fragment type. An example of the URI this proxy can manage is http://foo.bar.gr:53361?key=272b934d-e796-4c30-944c-44ec2aec7eb7#HTTP

Parameters:

locator - the locator URi that needs to be checked

Returns:

true is this proxy class can handle the locator, false otherwise