source: [view]
dojo.provide("dojox.storage.Provider");
dojo.declare("dojox.storage.Provider", null, {
// summary: A singleton for working with dojox.storage.
// description:
// dojox.storage exposes the current available storage provider on this
// platform. It gives you methods such as dojox.storage.put(),
// dojox.storage.get(), etc.
//
// For more details on dojox.storage, see the primary documentation
// page at
// http://manual.dojotoolkit.org/storage.html
//
// Note for storage provider developers who are creating subclasses-
// This is the base class for all storage providers Specific kinds of
// Storage Providers should subclass this and implement these methods.
// You should avoid initialization in storage provider subclass's
// constructor; instead, perform initialization in your initialize()
// method.
constructor: function(){
},
// SUCCESS: String
// Flag that indicates a put() call to a
// storage provider was succesful.
SUCCESS: "success",
// FAILED: String
// Flag that indicates a put() call to
// a storage provider failed.
FAILED: "failed",
// PENDING: String
// Flag that indicates a put() call to a
// storage provider is pending user approval.
PENDING: "pending",
// SIZE_NOT_AVAILABLE: String
// Returned by getMaximumSize() if this storage provider can not determine
// the maximum amount of data it can support.
SIZE_NOT_AVAILABLE: "Size not available",
// SIZE_NO_LIMIT: String
// Returned by getMaximumSize() if this storage provider has no theoretical
// limit on the amount of data it can store.
SIZE_NO_LIMIT: "No size limit",
// DEFAULT_NAMESPACE: String
// The namespace for all storage operations. This is useful if several
// applications want access to the storage system from the same domain but
// want different storage silos.
DEFAULT_NAMESPACE: "default",
// onHideSettingsUI: Function
// If a function is assigned to this property, then when the settings
// provider's UI is closed this function is called. Useful, for example,
// if the user has just cleared out all storage for this provider using
// the settings UI, and you want to update your UI.
onHideSettingsUI: null,
initialize: function(){
// summary:
// Allows this storage provider to initialize itself. This is
// called after the page has finished loading, so you can not do
// document.writes(). Storage Provider subclasses should initialize
// themselves inside of here rather than in their function
// constructor.
console.warn("dojox.storage.initialize not implemented");
},
isAvailable: function(){ /*Boolean*/
// summary:
// Returns whether this storage provider is available on this
// platform.
console.warn("dojox.storage.isAvailable not implemented");
},
put: function( /*string*/ key,
/*object*/ value,
/*function*/ resultsHandler,
/*string?*/ namespace){
// summary:
// Puts a key and value into this storage system.
// description:
// Example-
// var resultsHandler = function(status, key, message, namespace){
// alert("status="+status+", key="+key+", message="+message);
// };
// dojox.storage.put("test", "hello world", resultsHandler);
//
// Arguments:
//
// status - The status of the put operation, given by
// dojox.storage.FAILED, dojox.storage.SUCCEEDED, or
// dojox.storage.PENDING
// key - The key that was used for the put
// message - An optional message if there was an error or things failed.
// namespace - The namespace of the key. This comes at the end since
// it was added later.
//
// Important note: if you are using Dojo Storage in conjunction with
// Dojo Offline, then you don't need to provide
// a resultsHandler; this is because for Dojo Offline we
// use Google Gears to persist data, which has unlimited data
// once the user has given permission. If you are using Dojo
// Storage apart from Dojo Offline, then under the covers hidden
// Flash might be used, which is both asychronous and which might
// get denied; in this case you must provide a resultsHandler.
// key:
// A string key to use when retrieving this value in the future.
// value:
// A value to store; this can be any JavaScript type.
// resultsHandler:
// A callback function that will receive three arguments. The
// first argument is one of three values: dojox.storage.SUCCESS,
// dojox.storage.FAILED, or dojox.storage.PENDING; these values
// determine how the put request went. In some storage systems
// users can deny a storage request, resulting in a
// dojox.storage.FAILED, while in other storage systems a storage
// request must wait for user approval, resulting in a
// dojox.storage.PENDING status until the request is either
// approved or denied, resulting in another call back with
// dojox.storage.SUCCESS.
// The second argument in the call back is the key name that was being stored.
// The third argument in the call back is an optional message that
// details possible error messages that might have occurred during
// the storage process.
// namespace:
// Optional string namespace that this value will be placed into;
// if left off, the value will be placed into dojox.storage.DEFAULT_NAMESPACE
console.warn("dojox.storage.put not implemented");
},
get: function(/*string*/ key, /*string?*/ namespace){ /*Object*/
// summary:
// Gets the value with the given key. Returns null if this key is
// not in the storage system.
// key:
// A string key to get the value of.
// namespace:
// Optional string namespace that this value will be retrieved from;
// if left off, the value will be retrieved from dojox.storage.DEFAULT_NAMESPACE
// return: Returns any JavaScript object type; null if the key is not present
console.warn("dojox.storage.get not implemented");
},
hasKey: function(/*string*/ key, /*string?*/ namespace){
// summary: Determines whether the storage has the given key.
return !!this.get(key, namespace); // Boolean
},
getKeys: function(/*string?*/ namespace){ /*Array*/
// summary: Enumerates all of the available keys in this storage system.
// return: Array of available keys
console.warn("dojox.storage.getKeys not implemented");
},
clear: function(/*string?*/ namespace){
// summary:
// Completely clears this storage system of all of it's values and
// keys. If 'namespace' is provided just clears the keys in that
// namespace.
console.warn("dojox.storage.clear not implemented");
},
remove: function(/*string*/ key, /*string?*/ namespace){
// summary: Removes the given key from this storage system.
console.warn("dojox.storage.remove not implemented");
},
getNamespaces: function(){ /*string[]*/
console.warn("dojox.storage.getNamespaces not implemented");
},
isPermanent: function(){ /*Boolean*/
// summary:
// Returns whether this storage provider's values are persisted
// when this platform is shutdown.
console.warn("dojox.storage.isPermanent not implemented");
},
getMaximumSize: function(){ /* mixed */
// summary: The maximum storage allowed by this provider
// returns:
// Returns the maximum storage size
// supported by this provider, in
// thousands of bytes (i.e., if it
// returns 60 then this means that 60K
// of storage is supported).
//
// If this provider can not determine
// it's maximum size, then
// dojox.storage.SIZE_NOT_AVAILABLE is
// returned; if there is no theoretical
// limit on the amount of storage
// this provider can return, then
// dojox.storage.SIZE_NO_LIMIT is
// returned
console.warn("dojox.storage.getMaximumSize not implemented");
},
putMultiple: function( /*array*/ keys,
/*array*/ values,
/*function*/ resultsHandler,
/*string?*/ namespace){
// summary:
// Puts multiple keys and values into this storage system.
// description:
// Example-
// var resultsHandler = function(status, key, message){
// alert("status="+status+", key="+key+", message="+message);
// };
// dojox.storage.put(["test"], ["hello world"], resultsHandler);
//
// Important note: if you are using Dojo Storage in conjunction with
// Dojo Offline, then you don't need to provide
// a resultsHandler; this is because for Dojo Offline we
// use Google Gears to persist data, which has unlimited data
// once the user has given permission. If you are using Dojo
// Storage apart from Dojo Offline, then under the covers hidden
// Flash might be used, which is both asychronous and which might
// get denied; in this case you must provide a resultsHandler.
// keys:
// An array of string keys to use when retrieving this value in the future,
// one per value to be stored
// values:
// An array of values to store; this can be any JavaScript type, though the
// performance of plain strings is considerably better
// resultsHandler:
// A callback function that will receive three arguments. The
// first argument is one of three values: dojox.storage.SUCCESS,
// dojox.storage.FAILED, or dojox.storage.PENDING; these values
// determine how the put request went. In some storage systems
// users can deny a storage request, resulting in a
// dojox.storage.FAILED, while in other storage systems a storage
// request must wait for user approval, resulting in a
// dojox.storage.PENDING status until the request is either
// approved or denied, resulting in another call back with
// dojox.storage.SUCCESS.
// The second argument in the call back is the key name that was being stored.
// The third argument in the call back is an optional message that
// details possible error messages that might have occurred during
// the storage process.
// namespace:
// Optional string namespace that this value will be placed into;
// if left off, the value will be placed into dojox.storage.DEFAULT_NAMESPACE
for(var i = 0; i < keys.length; i++){
dojox.storage.put(keys[i], values[i], resultsHandler, namespace);
}
},
getMultiple: function(/*array*/ keys, /*string?*/ namespace){ /*Object*/
// summary:
// Gets the valuse corresponding to each of the given keys.
// Returns a null array element for each given key that is
// not in the storage system.
// keys:
// An array of string keys to get the value of.
// namespace:
// Optional string namespace that this value will be retrieved from;
// if left off, the value will be retrieved from dojox.storage.DEFAULT_NAMESPACE
// return: Returns any JavaScript object type; null if the key is not present
var results = [];
for(var i = 0; i < keys.length; i++){
results.push(dojox.storage.get(keys[i], namespace));
}
return results;
},
removeMultiple: function(/*array*/ keys, /*string?*/ namespace) {
// summary: Removes the given keys from this storage system.
for(var i = 0; i < keys.length; i++){
dojox.storage.remove(keys[i], namespace);
}
},
isValidKeyArray: function( keys) {
if(keys === null || keys === undefined || !dojo.isArray(keys)){
return false;
}
// JAC: This could be optimized by running the key validity test
// directly over a joined string
return !dojo.some(keys, function(key){
return !this.isValidKey(key);
}, this); // Boolean
},
hasSettingsUI: function(){ /*Boolean*/
// summary: Determines whether this provider has a settings UI.
return false;
},
showSettingsUI: function(){
// summary: If this provider has a settings UI, determined
// by calling hasSettingsUI(), it is shown.
console.warn("dojox.storage.showSettingsUI not implemented");
},
hideSettingsUI: function(){
// summary: If this provider has a settings UI, hides it.
console.warn("dojox.storage.hideSettingsUI not implemented");
},
isValidKey: function(/*string*/ keyName){ /*Boolean*/
// summary:
// Subclasses can call this to ensure that the key given is valid
// in a consistent way across different storage providers. We use
// the lowest common denominator for key values allowed: only
// letters, numbers, and underscores are allowed. No spaces.
if(keyName === null || keyName === undefined){
return false;
}
return /^[0-9A-Za-z_]*$/.test(keyName);
},
getResourceList: function(){ /* Array[] */
// summary:
// Returns a list of URLs that this
// storage provider might depend on.
// description:
// This method returns a list of URLs that this
// storage provider depends on to do its work.
// This list is used by the Dojo Offline Toolkit
// to cache these resources to ensure the machinery
// used by this storage provider is available offline.
// What is returned is an array of URLs.
// Note that Dojo Offline uses Gears as its native
// storage provider, and does not support using other
// kinds of storage providers while offline anymore.
return [];