org.apache.qpid.proton.engine

Interface Link

All Superinterfaces:

Endpoint, Extendable

All Known Subinterfaces:

Receiver, Sender

All Known Implementing Classes:

LinkImpl, ReceiverImpl, SenderImpl

public interface Link
extends Endpoint

Link The settlement mode defaults are: Sender settle mode - SenderSettleMode.MIXED. Receiver settle mode - ReceiverSettleMode.FIRST TODO describe the application's responsibility to honour settlement.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	advance() Attempts to advance the current delivery.
Delivery	current() Returns the current delivery
Delivery	delivery(byte[] tag) Create a delivery object based on the specified tag and adds it to the this link's delivery list and its connection work list.
Delivery	delivery(byte[] tag, int offset, int length) Create a delivery object based on the specified tag.
void	detach()
boolean	detached()
int	drained()
int	getCredit() Gets the credit balance for a link.
Symbol[]	getDesiredCapabilities() Gets the local link desired capabilities.
boolean	getDrain()
String	getName() Returns the name of the link
Symbol[]	getOfferedCapabilities() Gets the local link offered capabilities.
Map<Symbol,Object>	getProperties() Gets the local link properties.
int	getQueued() Gets the number of queued messages for a link.
ReceiverSettleMode	getReceiverSettleMode()
int	getRemoteCredit() Returns a [locally generated] view of credit at the remote peer by considering the current link credit count as well as the effect of any locally queued messages.
Symbol[]	getRemoteDesiredCapabilities() Gets the remote link desired capabilities, as conveyed from the peer via the Attach frame when attaching the link to the session.
Symbol[]	getRemoteOfferedCapabilities() Gets the remote link offered capabilities, as conveyed from the peer via the Attach frame when attaching the link to the session.
Map<Symbol,Object>	getRemoteProperties() Gets the remote link properties, as conveyed from the peer via the Attach frame when attaching the link to the session.
ReceiverSettleMode	getRemoteReceiverSettleMode()
SenderSettleMode	getRemoteSenderSettleMode()
Source	getRemoteSource()
Target	getRemoteTarget()
SenderSettleMode	getSenderSettleMode()
Session	getSession()
Source	getSource()
Target	getTarget()
int	getUnsettled()
Delivery	head() Returns the head delivery on the link.
Link	next(EnumSet<EndpointState> local, EnumSet<EndpointState> remote)
void	setDesiredCapabilities(Symbol[] desiredCapabilities) Sets the local link desired capabilities, to be conveyed to the peer via the Attach frame when attaching the link to the session.
void	setOfferedCapabilities(Symbol[] offeredCapabilities) Sets the local link offered capabilities, to be conveyed to the peer via the Attach frame when attaching the link to the session.
void	setProperties(Map<Symbol,Object> properties) Sets the local link properties, to be conveyed to the peer via the Attach frame when attaching the link to the session.
void	setReceiverSettleMode(ReceiverSettleMode receiverSettleMode) Sets the receiver settle mode.
void	setRemoteSenderSettleMode(SenderSettleMode remoteSenderSettleMode) Deprecated.
void	setSenderSettleMode(SenderSettleMode senderSettleMode) Sets the sender settle mode.
void	setSource(Source address) Sets the source for this link.
void	setTarget(Target address) Expected to be used in a similar manner to setSource(Source)

Methods inherited from interface org.apache.qpid.proton.engine.Endpoint

close, free, getCondition, getContext, getLocalState, getRemoteCondition, getRemoteState, open, setCondition, setContext

Methods inherited from interface org.apache.qpid.proton.engine.Extendable

attachments

Method Detail

getName

String getName()

Returns the name of the link

Returns:

the link name

delivery

Delivery delivery(byte[] tag)

Create a delivery object based on the specified tag and adds it to the this link's delivery list and its connection work list. TODO to clarify - this adds the delivery to the connection list. It is not yet clear why this is done or if it is useful for the application to be able to discover newly created deliveries from the Connection.getWorkHead().

Parameters:

tag - a tag for the delivery

Returns:

a new Delivery object

delivery

Delivery delivery(byte[] tag,
                int offset,
                int length)

Create a delivery object based on the specified tag. This form of the method is intended to allow the tag to be formed from a subsequence of the byte array passed in. This might allow more optimisation options in future but at present is not implemented.

Parameters:

tag - a tag for the delivery

offset - (currently ignored and must be 0)

length - (currently ignored and must be the length of the tag array

Returns:

a Delivery object

head

Delivery head()

Returns the head delivery on the link.

current

Delivery current()

Returns the current delivery

advance

boolean advance()

Attempts to advance the current delivery. Advances it to the next delivery if one exists, else null. The behaviour of this method is different for senders and receivers.

Returns:

true if it can advance, false if it cannot TODO document the meaning of the return value more fully. Currently Senderimpl only returns false if there is no current delivery

getSource

Source getSource()

getTarget

Target getTarget()

setSource

void setSource(Source address)

Sets the source for this link. The initiator of the link must always provide a Source. An application responding to the creation of the link should perform an application specific lookup on the getRemoteSource() to determine an actual Source. If it failed to determine an actual source, it should set null, and then go on to Endpoint.close() the link.

See Also:

"AMQP Spec 1.0 section 2.6.3"

setTarget

void setTarget(Target address)

Expected to be used in a similar manner to setSource(Source)

getRemoteSource

Source getRemoteSource()

See Also:

setSource(Source)

getRemoteTarget

Target getRemoteTarget()

See Also:

setTarget(Target)

next

Link next(EnumSet<EndpointState> local,
        EnumSet<EndpointState> remote)

getCredit

int getCredit()

Gets the credit balance for a link. Note that a sending link may still be used to send deliveries even if link credit is/reaches zero, however those deliveries will end up being queued by the link until enough credit is obtained from the receiver to send them over the wire. In this case the balance reported will go negative.

Returns:

the credit balance for the link

getQueued

int getQueued()

Gets the number of queued messages for a link. Links may queue deliveries for a number of reasons, for example there may be insufficient credit to send them to the receiver, they may not have yet had a chance to be written to the wire, or the receiving application has simply not yet processed them.

Returns:

the queued message count for the link

getUnsettled

int getUnsettled()

getSession

Session getSession()

getSenderSettleMode

SenderSettleMode getSenderSettleMode()

setSenderSettleMode

void setSenderSettleMode(SenderSettleMode senderSettleMode)

Sets the sender settle mode. Should only be called during link set-up, i.e. before calling Endpoint.open(). If this endpoint is the initiator of the link, this method can be used to set a value other than the default. If this endpoint is not the initiator, this method should be used to set a local value. According to the AMQP spec, the application may choose to accept the sender's suggestion (accessed by calling getRemoteSenderSettleMode()) or choose another value. The value has no effect on Proton, but may be useful to the application at a later point. In order to be AMQP compliant the application is responsible for honouring the settlement mode. See Link.

getRemoteSenderSettleMode

SenderSettleMode getRemoteSenderSettleMode()

See Also:

setSenderSettleMode(SenderSettleMode)

getReceiverSettleMode

ReceiverSettleMode getReceiverSettleMode()

setReceiverSettleMode

void setReceiverSettleMode(ReceiverSettleMode receiverSettleMode)

Sets the receiver settle mode. Used in analogous way to setSenderSettleMode(SenderSettleMode)

getRemoteReceiverSettleMode

ReceiverSettleMode getRemoteReceiverSettleMode()

See Also:

setReceiverSettleMode(ReceiverSettleMode)

setRemoteSenderSettleMode

@Deprecated
void setRemoteSenderSettleMode(SenderSettleMode remoteSenderSettleMode)

Deprecated.

TODO should this be part of the interface?

getProperties

Map<Symbol,Object> getProperties()

Gets the local link properties.

See Also:

setProperties(Map)

setProperties

void setProperties(Map<Symbol,Object> properties)

Sets the local link properties, to be conveyed to the peer via the Attach frame when attaching the link to the session. Must be called during link setup, i.e. before calling the Endpoint.open() method.

getRemoteProperties

Map<Symbol,Object> getRemoteProperties()

Gets the remote link properties, as conveyed from the peer via the Attach frame when attaching the link to the session.

Returns:

the properties Map conveyed by the peer, or null if there was none.

drained

int drained()

getRemoteCredit

int getRemoteCredit()

Returns a [locally generated] view of credit at the remote peer by considering the current link credit count as well as the effect of any locally queued messages.

Returns:

view of effective remote credit

getDrain

boolean getDrain()

detach

void detach()

detached

boolean detached()

setOfferedCapabilities

void setOfferedCapabilities(Symbol[] offeredCapabilities)

Sets the local link offered capabilities, to be conveyed to the peer via the Attach frame when attaching the link to the session. Must be called during link setup, i.e. before calling the Endpoint.open() method.

Parameters:

offeredCapabilities - the offered capabilities array to send, or null for none.

getOfferedCapabilities

Symbol[] getOfferedCapabilities()

Gets the local link offered capabilities.

Returns:

the offered capabilities array, or null if none was set.

See Also:

setOfferedCapabilities(Symbol[])

getRemoteOfferedCapabilities

Symbol[] getRemoteOfferedCapabilities()

Gets the remote link offered capabilities, as conveyed from the peer via the Attach frame when attaching the link to the session.

Returns:

the offered capabilities array conveyed by the peer, or null if there was none.

setDesiredCapabilities

void setDesiredCapabilities(Symbol[] desiredCapabilities)

Sets the local link desired capabilities, to be conveyed to the peer via the Attach frame when attaching the link to the session. Must be called during link setup, i.e. before calling the Endpoint.open() method.

Parameters:

desiredCapabilities - the desired capabilities array to send, or null for none.

getDesiredCapabilities

Symbol[] getDesiredCapabilities()

Gets the local link desired capabilities.

Returns:

the desired capabilities array, or null if none was set.

See Also:

setDesiredCapabilities(Symbol[])

getRemoteDesiredCapabilities

Symbol[] getRemoteDesiredCapabilities()

Gets the remote link desired capabilities, as conveyed from the peer via the Attach frame when attaching the link to the session.

Returns:

the desired capabilities array conveyed by the peer, or null if there was none.