dojo.provide("dojo.data.old.provider.Base");
dojo.require("dojo.lang.assert");
// -------------------------------------------------------------------
// Constructor
// -------------------------------------------------------------------
dojo.data.old.provider.Base = function() {
/**
* summary:
* A Data Provider serves as a connection to some data source,
* like a relational database. This data provider Base class
* serves as an abstract superclass for other data provider
* classes.
*/
this._countOfNestedTransactions = 0;
this._changesInCurrentTransaction = null;
};
// -------------------------------------------------------------------
// Public instance methods
// -------------------------------------------------------------------
dojo.data.old.provider.Base.prototype.beginTransaction = function() {
/**
* Marks the beginning of a transaction.
*
* Each time you call beginTransaction() you open a new transaction,
* which you need to close later using endTransaction(). Transactions
* may be nested, but the beginTransaction and endTransaction calls
* always need to come in pairs.
*/
if (this._countOfNestedTransactions === 0) {
this._changesInCurrentTransaction = [];
}
this._countOfNestedTransactions += 1;
};
dojo.data.old.provider.Base.prototype.endTransaction = function() {
/**
* Marks the end of a transaction.
*/
this._countOfNestedTransactions -= 1;
dojo.lang.assert(this._countOfNestedTransactions >= 0);
if (this._countOfNestedTransactions === 0) {
var listOfChangesMade = this._saveChanges();
this._changesInCurrentTransaction = null;
if (listOfChangesMade.length > 0) {
// dojo.debug("endTransaction: " + listOfChangesMade.length + " changes made");
this._notifyObserversOfChanges(listOfChangesMade);
}
}
};
dojo.data.old.provider.Base.prototype.getNewItemToLoad = function() {
return this._newItem(); // dojo.data.old.Item
};
dojo.data.old.provider.Base.prototype.newItem = function(/* string */ itemName) {
/**
* Creates a new item.
*/
dojo.lang.assertType(itemName, String, {optional: true});
var item = this._newItem();
if (itemName) {
item.set('name', itemName);
}
return item; // dojo.data.old.Item
};
dojo.data.old.provider.Base.prototype.newAttribute = function(/* string */ attributeId) {
/**
* Creates a new attribute.
*/
dojo.lang.assertType(attributeId, String, {optional: true});
var attribute = this._newAttribute(attributeId);
return attribute; // dojo.data.old.Attribute
};
dojo.data.old.provider.Base.prototype.getAttribute = function(/* string */ attributeId) {
dojo.unimplemented('dojo.data.old.provider.Base');
var attribute;
return attribute; // dojo.data.old.Attribute
};
dojo.data.old.provider.Base.prototype.getAttributes = function() {
dojo.unimplemented('dojo.data.old.provider.Base');
return this._arrayOfAttributes; // Array
};
dojo.data.old.provider.Base.prototype.fetchArray = function() {
dojo.unimplemented('dojo.data.old.provider.Base');
return []; // Array
};
dojo.data.old.provider.Base.prototype.fetchResultSet = function() {
dojo.unimplemented('dojo.data.old.provider.Base');
var resultSet;
return resultSet; // dojo.data.old.ResultSet
};
dojo.data.old.provider.Base.prototype.noteChange = function(/* dojo.data.old.Item */ item, /* string or dojo.data.old.Attribute */ attribute, /* anything */ value) {
var change = {item: item, attribute: attribute, value: value};
if (this._countOfNestedTransactions === 0) {
this.beginTransaction();
this._changesInCurrentTransaction.push(change);
this.endTransaction();
} else {
this._changesInCurrentTransaction.push(change);
}
};
dojo.data.old.provider.Base.prototype.addItemObserver = function(/* dojo.data.old.Item */ item, /* object */ observer) {
/**
* summary: Registers an object as an observer of an item,
* so that the object will be notified when the item changes.
*/
dojo.lang.assertType(item, dojo.data.old.Item);
item.addObserver(observer);
};
dojo.data.old.provider.Base.prototype.removeItemObserver = function(/* dojo.data.old.Item */ item, /* object */ observer) {
/**
* summary: Removes the observer registration for a previously
* registered object.
*/
dojo.lang.assertType(item, dojo.data.old.Item);
item.removeObserver(observer);
};
// -------------------------------------------------------------------
// Private instance methods
// -------------------------------------------------------------------
dojo.data.old.provider.Base.prototype._newItem = function() {
var item = new dojo.data.old.Item(this);
return item; // dojo.data.old.Item
};
dojo.data.old.provider.Base.prototype._newAttribute = function(/* String */ attributeId) {
var attribute = new dojo.data.old.Attribute(this);
return attribute; // dojo.data.old.Attribute
};
dojo.data.old.provider.Base.prototype._saveChanges = function() {
var arrayOfChangesMade = this._changesInCurrentTransaction;
return arrayOfChangesMade; // Array
};
dojo.data.old.provider.Base.prototype._notifyObserversOfChanges = function(/* Array */ arrayOfChanges) {
var arrayOfResultSets = this._getResultSets();
for (var i in arrayOfChanges) {
var change = arrayOfChanges[i];
var changedItem = change.item;
var arrayOfItemObservers = changedItem.getObservers();
for (var j in arrayOfItemObservers) {
var observer = arrayOfItemObservers[j];
observer.observedObjectHasChanged(changedItem, change);
}
for (var k in arrayOfResultSets) {
var resultSet = arrayOfResultSets[k];
var arrayOfResultSetObservers = resultSet.getObservers();
for (var m in arrayOfResultSetObservers) {
observer = arrayOfResultSetObservers[m];
observer.observedObjectHasChanged(resultSet, change);
}
}
}
};
dojo.data.old.provider.Base.prototype._getResultSets = function() {
dojo.unimplemented('dojo.data.old.provider.Base');
return []; // Array
};