QRemoteObjectReplica Class

A class interacting with (but not implementing) a Qt API on the Remote Object network More...

Header: #include <QRemoteObjectReplica>
qmake: QT += remoteobjects
Inherits: QObject
Inherited By:

QRemoteObjectDynamicReplica and QRemoteObjectRegistry

Public Types

enum State { Uninitialized, Default, Valid, Suspect, SignatureMismatch }


  • node : QRemoteObjectNode *
  • state : const State
  • 1 property inherited from QObject

Public Functions

bool isInitialized() const
bool isReplicaValid() const
QRemoteObjectNode *node() const
void setNode(QRemoteObjectNode *node)
State state() const
bool waitForSource(int timeout = 30000)
  • 32 public functions inherited from QObject


void initialized()
void stateChanged(State state, State oldState)

Additional Inherited Members

  • 1 public slot inherited from QObject
  • 11 static public members inherited from QObject
  • 9 protected functions inherited from QObject

Detailed Description

A class interacting with (but not implementing) a Qt API on the Remote Object network

A Remote Object Replica is a QObject proxy for another QObject (called the Source object). Once initialized, a replica can be considered a "latent copy" of the Source object. That is, every change to a Q_PROPERTY on the Source, or signal emitted by the Source will be updated/emitted by all Replica objects. Latency is introduced by process scheduling by any OSes involved and network communication latency. As long as the replica has been initialized and the communication is not disrupted, receipt and order of changes is guaranteed.

The isInitialized and state properties (and corresponding initialized()/stateChanged() signals) allow the state of a Replica to be determined.

While Qt Remote Objects (QtRO) handles the initialization and synchronization of Replica objects, there are numerous steps happening behind the scenes which can fail and that aren't encountered in single process Qt applications. See Troubleshooting for advice on how to handle such issues when using a remote objects network.

Member Type Documentation

enum QRemoteObjectReplica::State

This enum type specifies the various state codes associated with QRemoteObjectReplica states:

QRemoteObjectReplica::Uninitialized0initial value of DynamicReplica, where nothing is known about the replica before connection to source.
QRemoteObjectReplica::Default1initial value of static replica, where any defaults set in the .rep file are available so it can be used if necessary.
QRemoteObjectReplica::Valid2indicates the replica is connected, has good property values and can be interacted with.
QRemoteObjectReplica::Suspect3error state that occurs if the connection to the source is lost after it is initialized.
QRemoteObjectReplica::SignatureMismatch4error state that occurs if a connection to the source is made, but the source and replica are not derived from the same .rep (only possible for static Replicas).

Property Documentation

node : QRemoteObjectNode *

This property holds a pointer to the node this object was acquired from.

Access functions:

QRemoteObjectNode *node() const
void setNode(QRemoteObjectNode *node)

state : const State

Returns the replica state.

This property holds the replica QRemoteObjectReplica::State.

Access functions:

State state() const

Notifier signal:

void stateChanged(State state, State oldState)

Member Function Documentation

[signal] void QRemoteObjectReplica::initialized()

This signal is emitted once the replica is initialized.

See also isInitialized() and stateChanged().

bool QRemoteObjectReplica::isInitialized() const

Returns true if this replica has been initialized with data from the Source object. Returns false otherwise.

See also state().

bool QRemoteObjectReplica::isReplicaValid() const

Returns true if this replica has been initialized and has a valid connection with the node hosting the Source. Returns false otherwise.

See also isInitialized().

State QRemoteObjectReplica::state() const

Returns true if this replica has been initialized with data from the Source object. Returns false otherwise.

Note: Getter function for property state.

See also isInitialized().

[signal] void QRemoteObjectReplica::stateChanged(State state, State oldState)

This signal is emitted whenever a replica's state toggles between QRemoteObjectReplica::State.

The change in state is represented with state and oldState.

Note: Notifier signal for property state.

See also state() and initialized().

bool QRemoteObjectReplica::waitForSource(int timeout = 30000)

Blocking call that waits for the replica to become initialized or until the timeout (in ms) expires. Returns true if the replica is initialized when the call completes, false otherwise.

If timeout is -1, this function will not time out.

See also isInitialized() and initialized().

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