com.pushtechnology.diffusion.client.features

Interface UpdateConstraint.Factory

Enclosing interface:

UpdateConstraint

public static interface UpdateConstraint.Factory

Factory for the constraint types.

An instance can be obtained by calling Diffusion.updateConstraints().

Method Summary

Modifier and Type	Method and Description
UpdateConstraint.PartialJSON	jsonValue() Create a constraint that partially matches the current topic value.
UpdateConstraint	locked(Session.SessionLock lock) Create a constraint requiring a lock to be held by the session.
UpdateConstraint	noTopic() Create a constraint requiring the path to have no topic.
UpdateConstraint	noValue() Create a constraint requiring the topic to have no value.
<V> UpdateConstraint	value(V value) Create a constraint requiring the current value of a topic to match the supplied value.

Method Detail

locked

UpdateConstraint locked(Session.SessionLock lock)

Create a constraint requiring a lock to be held by the session.

This can be used to coordinate operations between multiple sessions.

Parameters:

lock - the lock

Returns:

the constraint

value

<V> UpdateConstraint value(V value)

Create a constraint requiring the current value of a topic to match the supplied value.

When a string, int64 or double topic is updated to a null value, the topic is set to have no value. Use the noValue() constraint to check if the topic has no value.

This is useful when changing the value of a topic. This constraint is unsatisfied if no topic is present at the path, making it unsuitable for operations that try to add topics.

Type Parameters:

V - the value type

Parameters:

value - the value

Returns:

the constraint

noValue

UpdateConstraint noValue()

Create a constraint requiring the topic to have no value.

This is useful when setting the first value of a topic. This constraint is unsatisfied if no topic is present at the path, making it unsuitable for operations that try to add topics.

Returns:

the constraint

noTopic

UpdateConstraint noTopic()

Create a constraint requiring the path to have no topic.

This is useful when setting the first value of a topic being added using addAndSet without changing the value if the topic already exists. This constraint is unsatisfied if a topic is present at the path, making it unsuitable for operations that try to set topics without adding them.

Returns:

the constraint

jsonValue

UpdateConstraint.PartialJSON jsonValue()

Create a constraint that partially matches the current topic value.

The topic must be a JSON topic. The UpdateConstraint.PartialJSON partially describes the structure of a JSON value.

Returns:

the constraint