org.planx.xmlstore.stores
Class RemoteXMLStore

java.lang.Object
  org.planx.xmlstore.stores.RemoteXMLStore

All Implemented Interfaces:

ExecXMLStore<ValueReference>, XMLStore<ValueReference>

public class RemoteXMLStore
extends Object
implements ExecXMLStore<ValueReference>

A direct connection to a remote XMLStore peer. Used for peer-to-peer transfers of data. In general, an application programmer would want to use DistributedXMLStore to get transparent location of data. However, this class is left exposed to application programmers for use in cases where the programmer does not wish to run a local XMLStore peer but rather connect to a remote XMLStore. Note, that in this case all transfers will go through the "gateway" XMLStore peer even though the XMLStore might consist of many XMLStore peers.

See NetworkProtocol for a description of the protocol.

Author:

Henning Niss, Thomas Ambus

Constructor Summary

RemoteXMLStore(InetAddress addr, int port)

RemoteXMLStore(InetSocketAddress sockaddr)

RemoteXMLStore(String host, int port)

Method Summary

void	close() The method is used to let the XMLStore properly commit all data to the underlying ressource, release resources, and so forth.
ValueReference	exec(ValueReference code, ValueReference args) Execute the code referenced by codeRef supplied with the argument reference by argsRef.
NameServer<ValueReference>	getNameServer() Returns the NameServer with the largest scope associated with this XMLStore.
Node	load(ValueReference ref) Loads XML data identified by a reference.
ValueReference	save(Node n) The subtree rooted at the specified Node is sent to the remote XMLStore and saved there.
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RemoteXMLStore

public RemoteXMLStore(String host,
                      int port)
               throws IOException,
                      UnknownHostException

Throws:

IOException

UnknownHostException

RemoteXMLStore

public RemoteXMLStore(InetSocketAddress sockaddr)
               throws IOException

Throws:

IOException

RemoteXMLStore

public RemoteXMLStore(InetAddress addr,
                      int port)
               throws IOException

Throws:

IOException

Method Detail

load

public Node load(ValueReference ref)
          throws IOException

Description copied from interface: XMLStore

Loads XML data identified by a reference. The returned value is semi-structured tree data, represented by a "root node" having 0 or more subtrees each represented by Nodes.

Specified by:

load in interface XMLStore<ValueReference>

Parameters:

ref - the Reference to the data

Returns:

node representing the loaded XML data

Throws:

IOException - if an error occurs during disk, network, etc access

UnknownReferenceException - if the data referenced is not stored in the XMLStore or the Reference is of a type not supported by the XMLStore

save

public ValueReference save(Node n)
                    throws IOException

The subtree rooted at the specified Node is sent to the remote XMLStore and saved there. A Reference to the root is returned.

Specified by:

save in interface XMLStore<ValueReference>

Parameters:

n - representing XML data in the form of semi-structured tree data

Returns:

a reference to the saved node/tree

Throws:

IOException - if an error occurs during disk, network, etc access

getNameServer

public NameServer<ValueReference> getNameServer()

Description copied from interface: XMLStore

Returns the NameServer with the largest scope associated with this XMLStore. That is, an XMLStore that stores data in a distributed setting should return a global NameServer for the XMLStore network in which it participates and not a local NameServer (even though it may also have access to such an entity).

Specified by:

getNameServer in interface XMLStore<ValueReference>

exec

public ValueReference exec(ValueReference code,
                           ValueReference args)
                    throws IOException,
                           ExecException

Description copied from interface: ExecXMLStore

Execute the code referenced by codeRef supplied with the argument reference by argsRef. Returns a reference to the result of the execution.

Specified by:

exec in interface ExecXMLStore<ValueReference>

Parameters:

code - the Reference to a binary node containing class code implementing StoredCode

args - reference to arguments

Returns:

a reference to the result

Throws:

IOException - if an error occurs during loading of code or arguments

ExecException

close

public void close()
           throws IOException

Description copied from interface: XMLStore

The method is used to let the XMLStore properly commit all data to the underlying ressource, release resources, and so forth. Once close has been issued on an XMLStore, the store is no longer available for handling requests. Any subsequent request to the store will result in an exception being thrown. An XMLStore implementation has to ensure that this happens.

Specified by:

close in interface XMLStore<ValueReference>

Throws:

IOException - if it is not possible to properly close the store

toString

public String toString()

Overrides:

toString in class Object