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ContextHub Javascript API Reference

The ContextHub Javascript API is available to your scripts when the ContextHub component has been added to the page.

ContextHub Constants

Constant values that the ContextHub Javascript API defines.

Event Constants

The following table lists the names events that occur for ContextHub Stores. See also ContextHub.Utils.Eventing.

Constant	Description	Value
`ContextHub.Constants.EVENT_NAMESPACE`	ContextHub’s event namespace	`ch`
`ContextHub.Constants.EVENT_ALL_STORES_READY`	Indicates that all required stores are registered, initialized and ready to be consumed	`all-stores-ready`
`ContextHub.Constants.EVENT_STORES_PARTIALLY_READY`	Indicates that not all stores were initialized within a given timeout	`stores-partially-ready`
`ContextHub.Constants.EVENT_STORE_REGISTERED`	Fired when a store is registered	`store-registered`
`ContextHub.Constants.EVENT_STORE_READY`	Indicates that stores is ready to work. It is triggered immediately after registration, except JSONP stores, where it is fired when data is fetched).	`store-ready`
`ContextHub.Constants.EVENT_STORE_UPDATED`	Fired when a store updates its persistence	`store-updated`
`ContextHub.Constants.PERSISTENCE_CONTAINER_NAME`	Persistence container name	`ContextHubPersistence`
`ContextHub.Constants.SERVICE_RAW_RESPONSE_KEY`	Stores specific persistence key name where raw JSON result is stored	`/_/raw-response`
`ContextHub.Constants.SERVICE_RESPONSE_TIME_KEY`	Stores specific timestamp indicating when JSON data was fetched	`/_/response-time`
`ContextHub.Constants.SERVICE_LAST_URL_KEY`	Stores specific url of JSON service used during last call	`/_/url`
`ContextHub.Constants.IS_CONTAINER_EXPANDED`	Indicates whether ContextHub’s UI is expanded	`/_/container-expanded`

UI Event Constants

The following table lists the names of events that occur for the ContextHub UI.

Constant	Description	Value
`ContextHub.Constants.EVENT_UI_MODE_REGISTERED`	Fired when a mode is registered	`ui-mode-registered`
`ContextHub.Constants.EVENT_UI_MODE_UNREGISTERED`	Fired when a mode is unregistered	`ui-mode-unregistered`
`ContextHub.Constants.EVENT_UI_MODE_RENDERER_REGISTERED`	Fired when a mode renderer is registered	`ui-mode-renderer-registered`
`ContextHub.Constants.EVENT_UI_MODE_RENDERER_UNREGISTERED`	Fired when a mode renderer is unregistered	`ui-mode-renderer-unregistered`
`ContextHub.Constants.EVENT_UI_MODE_ADDED`	Fired when a new mode is added	`ui-mode-added`
`ContextHub.Constants.EVENT_UI_MODE_REMOVED`	Fired when a mode is removed	`ui-mode-removed`
`ContextHub.Constants.EVENT_UI_MODE_SELECTED`	Fired when a mode is selected by the user	`ui-mode-selected`
`ContextHub.Constants.EVENT_UI_MODULE_REGISTERED`	Fired when a new module is registered	`ui-module-registered`
`ContextHub.Constants.EVENT_UI_MODULE_UNREGISTERED`	Fired when a module is unregistered	`ui-module-unregistered`
`ContextHub.Constants.EVENT_UI_MODULE_RENDERER_REGISTERED`	Fired when a module renderer is registered	`ui-module-renderer-registered`
`ContextHub.Constants.EVENT_UI_MODULE_RENDERER_UNREGISTERED`	Fired when a module renderer is unregistered	`ui-module-renderer-unregistered`
`ContextHub.Constants.EVENT_UI_MODULE_ADDED`	Fired when a new module is added	`ui-module-added`
`ContextHub.Constants.EVENT_UI_MODULE_REMOVED`	Fired when a module is removed	`ui-module-removed`
`ContextHub.Constants.EVENT_UI_CONTAINER_ADDED`	Fired when the UI container is added to the page	`ui-container-added`
`ContextHub.Constants.EVENT_UI_CONTAINER_OPENED`	Fired when the ContextHub UI is opened	`ui-container-opened`
`ContextHub.Constants.EVENT_UI_CONTAINER_CLOSED`	Fired when the ContextHub UI is collapsed	`ui-container-closed`
`ContextHub.Constants.EVENT_UI_PROPERTY_MODIFIED`	Fired when a property is modified	`ui-property-modified`
`ContextHub.Constants.EVENT_UI_RENDERED`	Fired every time the ContextHub UI is rendered (e.g. after a property change)	`ui-rendered`
`ContextHub.Constants.EVENT_UI_INITIALIZED`	Fired when UI container gets initialized	`ui-initialized`
`ContextHub.Constants.ACTIVE_UI_MODE`	Indicates active UI mode	`/_/active-ui-mode`

ContextHub Javascript API Reference

The ContextHub object provides access to all stores.

Functions (ContextHub)

getAllStores()

Returns all registered ContextHub stores.

This function has no parameters.

Returns

An object that contains all ContextHub stores. Each store is an object that uses the same name as the store.

Example

The following example retrieves all stores and then retrieves the geolocation store:

var allStores = ContextHub.getAllStores();
var geoloc = allStores.geolocation

getStore(name)

Retrieves a store as a Javascript object.

Parameters

name: The name with which the store was registered.

Returns

An object that represents the store.

Example

The following example retrieves the geolocation store:

var geoloc = ContextHub.getStore("geolocation");

ContextHub.SegmentEngine.Segment

Represents a ContextHub segment. Use the ContextHub.SegmentEngine.SegmentManager to obtain segments.

Functions (ContextHub.ContextEngine.Segment)

getName()

Returns the name of the segment as a String value.

getPath()

Returns the repository path of the segment definition as a String value.

ContextHub.SegmentEngine.SegmentManager

Provides access to ContextHub segments.

Functions (ContextHub.SegmentEngine.SegmentManager)

getResolvedSegments()

Returns the segments that are resolved in the current context. This function has no parameters.

Returns

An array of ContextHub.SegmentEngine.Segment objects.

ContextHub.Store.Core

The base class for ContextHub stores.

Properties (ContextHub.Store.Core)

eventing

A ContextHub.Utils.Eventing object. Use this object for binding functions to store events. For information about the default value and initialization, see init(name,config).

name

The name of the store.

persistence

A ContextHub.Utils.Persistence object. For information about the default value and initialization, see init(name,config).

Functions (ContextHub.Store.Core)

addAllItems(tree, options)

Merges a data object or an array with the store data. Each key/value pair in the object or array is added to the store (via the setItem function):

Object: Keys are the property names.
Array: Keys are the array indices.

Note that values can be objects.

Parameters

tree: (Object or array) The data to add to the store.
options: (Object) An optional object of options that is passed to the setItem function. For information, see the options parameter of setItem(key,value,options).

Returns

A boolean value:

A value of true indicates the data object was stored.
A value of false indicates that the data store is unchanged.

addReference(key, anotherKey)

Creates a reference from one key to another key. A key cannot reference itself.

Parameters

key: The key that references anotherKey.
anotherkey: They key that is referenced by key.

Returns

A boolean value:

A value of true indicates that the reference was added.
A value of false indicates that no reference was added.

announceReadiness()

Triggers the ready event for this store. This function has no parameters and returns no value.

clean()

Removes all data from the store. The function has no parameters and no return value.

getItem(key)

Returns the value that is associated with a key.

Parameters

key: (String) The key for which to return the value.

Returns

An Object that represents the value for the key.

getKeys(includeInternals)

Retrieves the keys from the store. Optionally you can retrieve the keys that are used internally by the ContextHub framework.

Parameters

includeInternals: A value of true includes internally-used keys in the results. These keys begin with the underscore (_) character. The default value is false.

Returns

An array of key names ( string values).

getReferences()

Retrieves the references from the store.

Returns

An array that uses referencing keys as indices for the referenced keys:

Referencing keys correspond with the key parameter of the addReference function.
Referenced keys correspond with the anotherKey parameter of the addReference function.

getTree(includeInternals)

Retrieves the data tree from the store. Optionally you can include the key/value pairs that are use internally by the ContextHub framework.

Parameters

includeInternals: A value of true includes internally-used key/value pairs in the results. The keys of this data begin with the underscore (_) character. The default value is false.

Returns

An object that represents the data tree. The keys are the property names of the object.

init(name, config)

Initializes the store.

Sets the store data to an empty object.
Sets the store references to an empty object.
The eventChannel is data:<name>, where <name> is the store name.
The storeDataKey is /store/<name>, where <name> is the store name.

Parameters

name: The name of the store.
config: An object that contains configuration properties:
- eventDeferring: Default value is 32.
- eventing: The ContextHub.Utils.Eventing object for this store. The default value is the ContextHub.eventing object uses.
- persistence: The ContextHub.Utils.Persistence object for this store. The default value is the ContextHub.persistence object.

isEventingPaused()

Determines whether eventing is paused for this store.

Returns

A boolean value:

true: Eventing is paused so that no events are triggered for this store.
false: Eventing is not paused so that events are triggered for this store.

pauseEventing()

Pauses eventing for the store so that no events are triggered. This function requires no parameters and returns no value.

removeItem(key, options)

Removes a key/value pair from the store.

When a key is removed, the function triggers the data event. The event data includes the store name, the name of the key that was removed, the value that was removed, new value for the key (null), and the action type of “remove”.

Optionally, you can prevent the triggering of the data event.

Parameters

key: (String) The name of the key to remove.
options: (Object) An object of options. The following object properties are valid:
- silent: A value of true prevents the triggering of the data event. The default value is false.

Returns

A boolean value:

A value of true indicates the key/value pair was removed.
A value of false indicates that the data store is unchanged because the key was not found in the store.

removeReference(key)

Removes a reference from the store.

Parameters

key: The key reference to remove. This parameter corresponds with the key parameter of the addReference function.

Returns

A boolean value:

A value of true indicates the reference was removed.
A value of false indicates that the key was not valid and the store is unchanged.

reset(keepRemainingData)

Resets the initial values of the store’s persisted data. Optionally, you can remove all other data from the store. Eventing is paused for this store while the store is reset. This function returns no value.

Initial values are provided in the initialValues property of the config object that is used to instantiate the store object.

Parameters

keepRemainingData: (Boolean) A value of true causes non-initial data to be persisted. A value of false causes all data to be removed except for the initial values.

resolveReference(key, retry)

Retrieves a referenced key. Optionally, you can specify the number of iterations to use for resolving the best match.

Parameters

key: (String) The key for which to resolve the reference. This key parameter corresponds with the key parameter of the addReference function.
retry: (Number) The number of iterations to use.

Returns

A string value that represents the referenced key. If no reference is resolved, the value of the key parameter is returned.

resumeEventing()

Resumes eventing for this store so that events are triggered. This function defines no parameters and returns no value.

setItem(key, value, options)

Adds a key/value pair to the store.

Triggers the data event only if the value for the key is different than the value that is currently stored for the key. You can optionally prevent the triggering of the data event.

The event data includes the store name, the key, the previous value, the new value, and the action type of set.

Parameters

key: (String) The name of the key.
options: (Object) An object of options. The following object properties are valid:
- silent: A value of true prevents the triggering of the data event. The default value is false.
value: (Object) The value to associate with the key.

Returns

A boolean value:

A value of true indicates the data object was stored.
A value of false indicates that the data store is unchanged.

ContextHub.Store.JSONPStore

A store that contains JSON data. The data is retrieved from an external JSONP service, or optionally from a service that returns JSON data. Specify the service details using the init function when you create an instance of this class.

The store uses in-memory persistance (Javascript variable). Store data is available only during the lifetime of the page.

ContextHub.Store.JSONPStore extends ContextHub.Store.Core and inherits the functions of that class.

Functions (ContextHub.Store.JSONPStore)

configureService(serviceConfig, override)

Configures the details for connecting to the JSONP service that this object uses. You can either update or replace the existing configuration. The function returns no value.

Parameters

serviceConfig: An object that contains the following properties:
- host: (String) The server name or IP address.
- jsonp: (Boolean) A value of true indicates that the service is a JSONP service, false otherwise. When true, the {callback: "ContextHub.Callbacks.Object.name} object is added to the service.params object.
- params: (Object) URL parameters represented as object properties. Parameter names are property names and parameter values are property values.
- path: (String) The path to the service.
- port: (Number) The port number of the service.
- secure: (String or Boolean) Determines the protocol to use for the service URL:
  - auto: //
  - true: https://
  - false: http://
override: (Boolean). A value of true causes the existing service configuration to be replaced by the properties of serviceConfig. A value of false causes the existing service configuration properties to be merged with the properties of serviceConfig.

getRawResponse()

Returns the raw response that is cached since the last call to the JSONP service. The function requires no parameters.

Returns

An object that represents the raw response.

getServiceDetails()

Retrieves the service object for this ContextHub.Store.JSONPStore object. The service object contains all of the information required to create the service URL.

Returns

An object with the following properties:

host: (String) The server name or IP address.
jsonp: (Boolean) A value of true indicates that the service is a JSONP service, false otherwise. When true, the {callback: "ContextHub.Callbacks.Object.name} object is added to the service.params object.
params: (Object) URL parameters represented as object properties. Parameter names are property names and parameter values are property values.
path: (String) The path to the service.
port: (Number) The port number of the service.
secure: (String or Boolean) Determines the protocol to use for the service URL:
- auto: //
- true: https://
- false: http://

getServiceURL(resolve)

Retrieves the URL of the JSONP service.

Parameters

resolve: (Boolean) Determines whether to include resolved parameters in the URL. A value of true resolves parameters, and false does not.

Returns

A string value that represents the service URL.

init(name, config)

initializes the ContextHub.Store.JSONPStore object.

Parameters

name: (String) The name of the store.
config: (Object) An object that contains the service property. The JSONPStore object uses the properties of the service object to construct the URL of the JSONP service:
- eventDeferring: 32.
- eventing: The ContextHub.Utils.Eventing object for this store. The default value is the ContextHub.eventing object.
- persistence: The ContextHub.Utils.Persistence object for this store. By default, memory persistence is used (Javascript object).
- service: (Object)
  - host: (String) The server name or IP address.
  - jsonp: (Boolean) A value of true indicates that the service is a JSONP service, false otherwise. When true, the {callback: "ContextHub.Callbacks.*Object.name*}object is added to service.params.
  - params: (Object) URL parameters represented as object properties. Parameter names and values are the object property names and values, respectively.
  - path: (String) The path to the service.
  - port: (Number) The port number of the service.
  - secure: (String or Boolean) Determines the protocol to use for the service URL:
    - auto: //
    - true: https://
    - false: http://
  - timeout: (Number) The amount of time to wait for the JSONP service to respond before timing out, in milliseconds.
    - ttl: The minimum amount of time in milliseconds that passes between calls to the JSONP service. (See the queryService function).

queryService(reload)

Queries the remote JSONP service and caches the response. If the amount of time since the previous call to this function is less than the value of config.service.ttl, the service is not called and the cached response is not changed. Optionally, you can force the service to be called. The config.service.ttlproperty is set when calling the init function to initialize the store.

Triggers the ready event when the query is finished. If the JSONP service URL is not set, the function does nothing.

Parameters

reload: (Boolean) A value of true removes the cached response and forces the JSONP service to be called.

reset

Resets the initial values of the store’s persisted data and then calls the JSONP service. Optionally, you can remove all other data from the store. Eventing is paused for this store while the initial values are reset. This function returns no value.

Initial values are provided in the initialValues property of the config object that is used to instantiate the store object.

Parameters

keepRemainingData: (Boolean) A value of true causes non-initial data to be persisted. A value of false causes all data to be removed except for the initial values.

resolveParameter(f)

Resolves the given parameter.

ContextHub.Store.PersistedJSONPStore

ContextHub.Store.PersistedJSONPStore extends ContextHub.Store.JSONPStore so it inherits all of the functions of that class. However, the data that is retrieved from the JSONP service is persisted according to the configuration of ContextHub persistence. (See Persistence Modes:)

ContextHub.Store.PersistedStore

ContextHub.Store.PersistedStore extends ContextHub.Store.Core so it inherits all of the functions of that class. The data in this store is persisted according to the configuration of ContextHub persistence.

ContextHub.Store.SessionStore

ContextHub.Store.SessionStore extends ContextHub.Store.Core so it inherits all of the functions of that class. The data in this store is persisted using in-memory persistance (Javascript object).

ContextHub.UI

Manages UI modules and UI module renderers.

Functions (ContextHub.UI)

registerRenderer(moduleType, renderer, dontRender)

Registers a UI module renderer with ContextHub. After the renderer is registered, it can be used to create UI modules. Use this function when you are extending ContextHub.UI.BaseModuleRenderer to create a custom UI Module renderer.

Parameters

moduleType: (String) The identifier for the UI module renderer. If a renderer is already registered using the specified value, the existing renderer is unregistered before this renderer is registered.
renderer: (String) The name of the class that renders the UI module.
dontRender: (Boolean) Set to true to prevent the ContextHub UI from being rendered after the renderer is registered. The default value is false.

Example

The following example registers a renderer as the contexthub.browserinfo module type.

ContextHub.UI.registerRenderer('contexthub.browserinfo', new SurferinfoRenderer());

A utility class for interacting with cookies.

exists(key)

Determines whether a cookie exists.

Parameters

key: A String that contains the key of the cookie for which you are testing.

Returns

A boolean value of true indicates that the cookie exists.

Example

if (ContextHub.Utils.Cookie.exists("name")) {
   // conditionally-executed code
}

getAllItems(filter)

Returns all cookies that have keys that match a filter.

Parameters

filter: (Optional) Criteria for matching cookie keys. To return all cookies, specify no value. The following types are supported:
- String: The string is compared to the cookie key.
- Array: Each item in the array is a filter.
- A RegExp object: The test function of the object is used to match cookie keys.
- A function: A function that tests a cookie key for a match. The function must take the cookie key as a parameter and return true if the test confirms a match.

Returns

An object of cookies. Object properties are cookie keys and key values are cookie values.

Example

ContextHub.Utils.Cookie.getAllItems([/^cq-authoring/, /^cq-editor/])

getItem(key)

Returns a cookie value.

Parameters

key: The key of the cookie for which you want the value.

Returns

The cookie value, or null if no cookie was found for the key.

Example

ContextHub.Utils.Cookie.getItem("name");

getKeys(filter)

Returns an array of the keys of existing cookies that match a filter.

Parameters

filter: Criteria for matching cookie keys. The following types are supported:
- String: The string is compared to the cookie key.
- Array: Each item in the array is a filter.
- A RegExp object: The test function of the object is used to match cookie keys.
- A function: A function that tests a cookie key for a match. The function must take the cookie key as a parameter and return true if the test confirms a match.

Returns

An array of strings where each string is the key of a cookie that matches the filter.

Example

ContextHub.Utils.Cookie.getKeys([/^cq-authoring/, /^cq-editor/])

removeItem(key, options)

Removes a cookie. To remove the cookie, the value is set to an empty string and the expiry date is set to the day before the current date.

Parameters

key: A String value that represents the key of the cookie to remove.
options: An object that contains property values for configuring the cookie attributes. See the setItem function for information. The expires property has no effect.

Returns

This function does not return a value.

Example

ContextHub.Utils.Cookie.vanish([/^cq-authoring/, 'cq-scrollpos']);

setItem(key, value, options)

Creates a cookie of the given key and value, and adds the cookie to the current document. Optionally, you can specify options that configure the attributes of the cookie.

Parameters

key: A String that contains the key of the cookie.
value: A String that contains the cookie value.
options: (Optional) An object that contains any of the following properties that configure the cookie attributes:
- expires: A date or number value that specifies when the cookie expires. A date value specifies the absolute time of expiry. A number (in days) sets the time of expiry to the current time plus the number. The default value is undefined.
- secure: A boolean value that specifies the Secure attribute of the cookie. The default value is false.
- path: A String value to use as the Path attribute of the cookie. The default value is undefined.

Returns

The cookie with the set value.

Example

ContextHub.Utils.Cookie.setItem("name", "mycookie", {
    expires: 3,
    domain: 'localhost',
    path: '/some/directory',
    secure: true
});

Removes all cookies that match a given filter. Cookies are matched using the getKeys function and removed using the removeItem function.

Parameters

filter: The filter argument to use in the call to the getKeys function.
options: The options argument to use in the call to the removeItem function.

Returns

This function does not return a value.

ContextHub.Utils.Eventing

Enables you to bind and unbind functions to ContextHub store events. Access ContextHub.Utils.Eventing objects for a store using the eventing property of the store.

Functions (ContextHub.Utils.Eventing)

off(name, selector)

Unbinds a function from an event.

Parameters

name: The name of the event for which you are unbinding the function.
selector: The selector that identifies the bind. (See the selector parameter for the on and once functions).

Returns

This function returns no value.

on(name, handler, selector, triggerForPastEvents)

Binds a function to an event. The function is called every time the event occurs. Optionally, the function can be called for events that have occurred in the past, before the binding is established.

Parameters

name: (String) The name of the event to which you are binding the function.
handler: (Function) The function to bind to the event.
selector: (String) A unique identifier for the bind. You need the selector to identify the bind if you want to use the off function to remove the bind.
triggerForPastEvents: (Boolean) Indicates whether the handler should be executed for events that occurred in the past. A value of true calls the handler for past events. A value of false calls the handler for future events. The default value is true.

Returns

When the triggerForPastEvents argument is true, this function returns a boolean value that indicates whether the event occurred in the past:

true: The event occurred in the past and the handler will be called.
false: The event has not occurred in the past.

If triggerForPastEvents is false, this function returns no value.

Example

The following example binds a function to the data event of the geolocation store. The function populates an element on the page with the value for the latitude data item from the store.

<div class="location">
    <p>latitude: <span id="lat"></span></p>
</div>

<script>
    var geostore = ContextHub.getStore("geolocation");
    geostore.eventing.on(ContextHub.Constants.EVENT_DATA_UPDATE,getlat,"getlat");

    function getlat(){
       latitude = geostore.getItem("latitude");
       $("#lat").html(latitude);
    }
</script>

once(name, handler, selector, triggerForPastEvents)

Binds a function to an event. The function is called only once, for the first occurrence of the event. Optionally, the function can be called for the event that has occurred in the past, before the binding is established.

Parameters

name: (String) The name of the event to which you are binding the function.
handler: (Function) The function to bind to the event.
selector: (String) A unique identifier for the bind. You need the selector to identify the bind if you want to use the off function to remove the bind.
triggerForPastEvents: (Boolean) Indicates whether the handler should be executed for events that occurred in the past. A value of true calls the handler for past events. A value of false calls the handler for future events. The default value is true.

Returns

When the triggerForPastEvents argument is true, this function returns a boolean value that indicates whether the event occurred in the past:

true: The event occurred in the past and the handler will be called.
false: The event has not occurred in the past.

If triggerForPastEvents is false, this function returns no value.

ContextHub.Utils.inheritance

A utility class that enables an object to inherit the properties and methods of another object.

Functions (ContextHub.Utils.inheritance)

inherit(child, parent)

Causes an object to inherit the properties and methods of another object.

Parameters

child: (Object) The object that inherits.
parent: (Object) The object that defines the properties and methods that are inherited.

ContextHub.Utils.JSON

Provides functions for serializing objects into JSON format and deserializing JSON strings into objects.

Functions (ContextHub.Utils.JSON)

parse(data)

Parses a string value as JSON and converts it into a javascript object.

Parameters

data: A string value in JSON format.

Returns

A Javascript object.

Example

The code:

ContextHub.Utils.JSON.parse("{'city':'Basel','country':'Switzerland','population':'173330'}");

Returns the following object:

Object {
   city: "Basel",
   country: "Switzerland",
   population: 173330
}

stringify(data)

Serializes Javascript values and objects into string values of JSON format.

Parameters

data: The value or object to serialize. This function supports boolean, array, number, string, and date values.

Returns

The serialized string value. When data is a R egExp value, this function returns an empty object. When data is a function, returns undefined.

Example

The following code:

ContextHub.Utils.JSON.stringify({
   city: "Basel",
   country: "Switzerland",
   population: 173330
});

Returns:

"{'city':'Basel','country':'Switzerland','population':'173330'}":

ContextHub.Utils.JSON.tree

This class facilitates the manipulation of data objects that to be stored or are retrieved from ContextHub stores.

Functions (ContextHub.Utils.JSON.tree)

addAllItems()

Creates a copy of a data object and adds to it the data tree from a second object. The function returns the copy and does not modify either of the original objects. When the data trees of the two objects contain identical keys, the value of the second object overwrites the value of the first object.

Parameters

tree: The object that is copied.
secondTree: The object that is merged with the copy of the tree object.

Returns

An object that contains the merged data.

cleanup()

Creates a copy of an object, finds and removes items in the data tree that contain no values, null values, or undefined values, and returns the copy.

Parameters

tree: The object to clean.

Returns

A copy of tree that is cleaned.

getItem()

Retrieves the value from an object for the a key.

Parameters

tree: The data object.
key: The key for the value that you want to retrieve.

Returns

The value that corresponds with the key. When the key has child keys, this function returns a complex object. When the type of the value for the key is undefined, null is returned.

Example

Consider the following Javascript object:

myObject {
  user: {
    location: {
      city: "Basel",
        details: {
          population: 173330,
          elevation: 260
        }
      }
    }
  }

The following example code returns the value 260:

ContextHub.Utils.JSON.tree.getItem(myObject, "/user/location/details/elevation");

The following example code retrieves the value for a key that has child keys:

ContextHub.Utils.JSON.tree.getItem(myObject, "/user");

The function returns the following object:

Object {
  location: {
    city: "Basel",
    details: {
      population: 173330,
      elevation: 260
    }
  }
}

getKeys()

Retrieves all keys from the data tree of an object. Optionally, you can retrieve only the keys of the children of a specific key. You can also optionally specify a sort order of the retrieved keys.

Parameters

tree: The object from which to retrieve the keys of the data tree.
parent: (Optional) The key of an item in the data tree for which you want to retrieve the keys of the child items.
order: (Optional) A function that determines the sort order of the returned keys. (See Array.prototype.sort on the Mozilla Developer Network.)

Returns

An array of keys.

Example

Consider the following object:

myObject {
  location: {
    weather: {
      temperature: "28C",
      humidity: "77%",
      precipitation: "10%",
      wind: "8km/h"
    },
    city: "Basel",
    country: "Switzerland",
    longitude: 7.5925727,
    latitude: 47.557421
  }
}

The ContextHub.Utils.JSON.tree.getKeys(myObject); script returns the following array:

["/location", "/location/city", "/location/country", "/location/latitude", "/location/longitude", "/location/weather", "/location/weather/humidity", "/location/weather/precipitation", "/location/weather/temperature", "/location/weather/wind"]

removeItem()

Creates a copy of a given object, removes the specified branch from the data tree, and returns the modified copy.

Parameters

tree: A data object.
key: The key to remove.

Returns

A copy of the original data object with the key removed.

Example

Consider the following object:

myObject {
  one: {
    foo: "bar",
    two: {
      three: {
        four: {
          five: 5,
          six: 6
        }
      }
    }
  }
}

The following example script removes the /one/two/three/four branch from the data tree:

myObject = ContextHub.Utils.JSON.tree.removeItem(myObject, "/one/two/three/four");

The function returns the following object:

myObject {
  one: {
    foo: "bar"
  }
}

sanitizeKey(key)

Sanitizes string values to make them usable as keys. To sanitize a string, this function performs the following actions:

Reduces multiple consecutive forward slashes to a single slash.
Removes whitespace from the beginning and ending of the string.
Splits the result into an array of strings that are demarcated by slashes.

Use the resultant array to create a usable key.

Parameters

key: The string to sanitize.

Returns

An array of string values where each string is the portion of the key that was demarcated by slashes. represents the sanitized key. If the sanitized array has a length of zero, this function returns null.

Example

The following code sanitizes a string to produce the array ["this", "is", "a", "path"], and then generates the key "/this/is/a/path" from the array:

var key = " / this////is/a/path ";
ContextHub.Utils.JSON.tree.sanitizeKey(key)
"/" + ContextHub.Utils.JSON.tree.sanitizeKey(key).join("/");

setItem(tree, key, value)

Adds a key/value pair to the data tree of a copy of an object. For information about data trees, see Persistence.

Parameters

tree: A data object.
key: The key to associate with the value that you are adding. The key is the path to the item in the data tree. This function calls ContextHub.Utils.JSON.tree.sanitize to sanitize the key before adding it.
value: The value to add to the data tree.

Returns

A copy of the tree object that includes the key/ value pair.

Example

Consider the following Javascript code:

var myObject = {
     user: {
        location: {
           city: "Basel"
           }
        }
     };

var myKey = "/user/location/details";

var myValue = {
      population: 173330,
      elevation: 260
     };

myObject = ContextHub.Utils.JSON.tree.setItem(myObject, myKey, myValue);

ContextHub.Utils.storeCandidates

Enables you to register store candidates and obtain registered store candidates.

Functions (ContextHub.Utils.storeCandidates)

getRegisteredCandidates(storeType)

Returns the store types that are registered as store candidates. Either retrieve the registered candidates of a specific store type or of all store types.

Parameters

storeType: (String) The name of the store type. See the storeType parameter of the ContextHub.Utils.storeCandidates.registerStoreCandidate function.

Returns

An object of store types. The object properties are the store type names, and the property values are an array of registered store candidates.

getStoreFromCandidates(storeType)

Returns a store type from the registered candidates. If more than one store type of the same name is registered, the function returns the store type with the highest priority.

Parameters

storeType: (String) The name of the store candidate. See the storeType parameter of the ContextHub.Utils.storeCandidates.registerStoreCandidate function.

Returns

An object that represents the registered store candidate. If the requested store Type is not registered, an error is thrown.

getSupportedStoreTypes()

Returns the names of the store types that are registered as store candidates. This function requires no parameters.

Returns

An array of string values, where each string is the storetype with which a store candidate was registered. See the storeType parameter of the ContextHub.Utils.storeCandidates.registerStoreCandidate function.

registerStoreCandidate(store, storeType, priority, applies)

Registers a store object as a store candidate using a name and priority.

The priority is a number that indicates the importance of same-named stores. When a store candidate is registered using the same name as an already-registered store candidate, the candidate with the higher priority is used. When registering a store candidate, the store is registered only if the priority is higher than same-named registered store candidates.

Parameters

store: (Object) The store object to register as a store candidate.
storeType: (String) The name of the store candidate. This value is required when creating an instance of the store candidate.
priority: (Number) The priority of the store candidate.
applies: (Function) The function to invoke that evaluates the applicability of the store in the current environment. The function must return true if the store is applicable, and false otherwise. The default value is a function that returns true: function() {return true;}

Example

ContextHub.Utils.storeCandidates.registerStoreCandidate(myStoreCandidate,
                                'contexthub.mystorecandiate', 0);