source: Dev/trunk/src/client/dojox/wire/DataWire.js @ 532

dojo.provide("dojox.wire.DataWire");

dojo.require("dojox.wire.Wire");

dojo.declare("dojox.wire.DataWire", dojox.wire.Wire, {
        // summary:
        //              A Wire for item attributes of data stores
        // description:
        //              This class accesses item attributes of data stores with a dotted
        //              notation of attribute names specified to 'attribute' property,
        //              using data APIs of a data store specified to 'dataStore' property.
        //              The root object for this class must be an item of the data store.
        //              Intermediate attribute names in the dotted notation specify
        //              attributes for child items, which are used for repeated calls to
        //              data APIs until reached to a descendant attribute.
        //              Attribute names may have an array index, such as "a[0]", to
        //              identify an array element of the attribute value.
        
        _wireClass: "dojox.wire.DataWire",

        constructor: function(/*Object*/ args){
                // summary:
                //              Initialize properties
                // description:
                //              If 'dataStore' property is not specified, but 'parent' property
                //              is specified, 'dataStore' property is copied from the parent.
                // args:
                //              Arguments to initialize properties:
                //
                //              - dataStore: A data store
                //              - attribute: A dotted notation to a descendant attribute
                if(!this.dataStore && this.parent){
                        this.dataStore = this.parent.dataStore;
                }
        },
        _getValue: function(/*Object*/object){
                // summary:
                //              Return an attribute value of an item
                // description:
                //              This method uses a root item passed in 'object' argument and
                //              'attribute' property to call getValue() method of
                //              'dataStore'.
                //              If an attribute name have an array suffix ("[]"), getValues()
                //              method is called, instead.
                //              If an index is specified in the array suffix, an array element
                //              for the index is returned, instead of the array itself.
                // object:
                //              A root item
                // returns:
                //              A value found, otherwise 'undefined'
                if(!object || !this.attribute || !this.dataStore){
                        return object; //Object
                }

                var value = object;
                var list = this.attribute.split('.');
                for(var i in list){
                        value = this._getAttributeValue(value, list[i]);
                        if(!value){
                                return undefined; //undefined
                        }
                }
                return value; //anything
        },

        _setValue: function(/*Object*/object, /*anything*/value){
                // summary:
                //              Set an attribute value to an item
                // description:
                //              This method uses a root item passed in 'object' argument and
                //              'attribute' property to identify an item.
                //              Then, setValue() method of 'dataStore' is called with a leaf
                //              attribute name and 'value' argument.
                //              If an attribute name have an array suffix ("[]"), setValues()
                //              method is called, instead.
                //              If an index is specified in the array suffix, an array element
                //              for the index is set to 'value', instead of the array itself.
                // object:
                //              A root item
                // value:
                //              A value to set
                // returns:
                //              'object', or 'undefined' for invalid attribute
                if(!object || !this.attribute || !this.dataStore){
                        return object; //Object
                }

                var item = object;
                var list = this.attribute.split('.');
                var last = list.length - 1;
                for(var i = 0; i < last; i++){
                        item = this._getAttributeValue(item, list[i]);
                        if(!item){
                                return undefined; //undefined
                        }
                }
                this._setAttributeValue(item, list[last], value);
                return object; //Object
        },

        _getAttributeValue: function(/*Object*/item, /*String*/attribute){
                // summary:
                //              Return an attribute value of an item
                // description:
                //              This method uses an item passed in 'item' argument and
                //              'attribute' argument to call getValue() method of 'dataStore'.
                //              If an attribute name have an array suffix ("[]"), getValues()
                //              method is called, instead.
                //              If an index is specified in the array suffix, an array element
                //              for the index is returned, instead of the array itself.
                // item:
                //              An item
                // attribute:
                //              An attribute name
                // returns:
                //              A value found, otherwise 'undefined'
                var value = undefined;
                var i1 = attribute.indexOf('[');
                if(i1 >= 0){
                        var i2 = attribute.indexOf(']');
                        var index = attribute.substring(i1 + 1, i2);
                        attribute = attribute.substring(0, i1);
                        var array = this.dataStore.getValues(item, attribute);
                        if(array){
                                if(!index){ // return array for "attribute[]"
                                        value = array;
                                }else{
                                        value = array[index];
                                }
                        }
                }else{
                        value = this.dataStore.getValue(item, attribute);
                }
                return value; //anything
        },

        _setAttributeValue: function(/*Object*/item, /*String*/attribute, /*anything*/value){
                // summary:
                //              Set an attribute value to an item
                // description:
                //              This method uses an item passed in 'item' argument and
                //              'attribute' argument to call setValue() method of 'dataStore'
                //              with 'value' argument.
                //              If an attribute name have an array suffix ("[]"), setValues()
                //              method is called, instead.
                //              If an index is specified in the array suffix, an array element
                //              for the index is set to 'value', instead of the array itself.
                // item:
                //              An item
                // attribute:
                //              An attribute name
                // value:
                //              A value to set
                var i1 = attribute.indexOf('[');
                if(i1 >= 0){
                        var i2 = attribute.indexOf(']');
                        var index = attribute.substring(i1 + 1, i2);
                        attribute = attribute.substring(0, i1);
                        var array = null;
                        if(!index){ // replace whole array for "attribute[]"
                                array = value;
                        }else{
                                array = this.dataStore.getValues(item, attribute);
                                if(!array){
                                        array = [];
                                }
                                array[index] = value;
                        }
                        this.dataStore.setValues(item, attribute, array);
                }else{
                        this.dataStore.setValue(item, attribute, value);
                }
        }
});