/** * @author Ed Spencer * @class Ext.data.Field * @extends Object * ** *Fields are used to define what a Model is. They aren't instantiated directly - instead, {@link Ext#regModel} * creates a Field instance for each field configured in a {@link Ext.data.Model Model}. For example, we might set up a * model like this:
** *Ext.regModel('User', { fields: [ 'name', 'email', {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'} ] });
Four fields will have been created for the User Model - name, email, age and gender. Note that we specified a * couple of different formats here; if we only pass in the string name of the field (as with name and email), the * field is set up with the 'auto' type. It's as if we'd done this instead:
** *Ext.regModel('User', { fields: [ {name: 'name', type: 'auto'}, {name: 'email', type: 'auto'}, {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'} ] });
Types and conversion
* *The {@link #type} is important - it's used to automatically convert data passed to the field into the correct * format. In our example above, the name and email fields used the 'auto' type and will just accept anything that is * passed into them. The 'age' field had an 'int' type however, so if we passed 25.4 this would be rounded to 25.
* *Sometimes a simple type isn't enough, or we want to perform some processing when we load a Field's data. We can * do this using a {@link #convert} function. Here, we're going to create a new field based on another:
*
Ext.regModel('User', { fields: [ 'name', 'email', {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'}, { name: 'firstName', convert: function(value, record) { var fullName = record.get('name'), splits = fullName.split(" "), firstName = splits[0]; return firstName; } } ] });
Now when we create a new User, the firstName is populated automatically based on the name:
*
var ed = Ext.ModelMgr.create({name: 'Ed Spencer'}, 'User');
console.log(ed.get('firstName')); //logs 'Ed', based on our convert function
*
* In fact, if we log out all of the data inside ed, we'll see this:
*
console.log(ed.data);
//outputs this:
{
age: 0,
email: "",
firstName: "Ed",
gender: "Unknown",
name: "Ed Spencer"
}
*
* The age field has been given a default of zero because we made it an int type. As an auto field, email has * defaulted to an empty string. When we registered the User model we set gender's {@link #defaultValue} to 'Unknown' * so we see that now. Let's correct that and satisfy ourselves that the types work as we expect:
*
ed.set('gender', 'Male');
ed.get('gender'); //returns 'Male'
ed.set('age', 25.4);
ed.get('age'); //returns 25 - we wanted an int, not a float, so no decimal places allowed
*
*/
Ext.define('Ext.data.Field', {
requires: ['Ext.data.Types', 'Ext.data.SortTypes'],
constructor : function(config) {
if (Ext.isString(config)) {
config = {name: config};
}
Ext.apply(this, config);
var types = Ext.data.Types,
st = this.sortType,
t;
if (this.type) {
if (Ext.isString(this.type)) {
this.type = types[this.type.toUpperCase()] || types.AUTO;
}
} else {
this.type = types.AUTO;
}
// named sortTypes are supported, here we look them up
if (Ext.isString(st)) {
this.sortType = Ext.data.SortTypes[st];
} else if(Ext.isEmpty(st)) {
this.sortType = this.type.sortType;
}
if (!this.convert) {
this.convert = this.type.convert;
}
},
/**
* @cfg {String} name
* The name by which the field is referenced within the Model. This is referenced by, for example,
* the dataIndex
property in column definition objects passed to {@link Ext.grid.ColumnModel}.
* Note: In the simplest case, if no properties other than name
are required, a field
* definition may consist of just a String for the field name.
{@link Ext.data.Field#convert convert}
* has not been specified. This may be specified as a string value. Possible values are
* This may also be specified by referencing a member of the {@link Ext.data.Types} class.
*Developers may create their own application-specific data types by defining new members of the * {@link Ext.data.Types} class.
*/ /** * @cfg {Function} convert * (Optional) A function which converts the value provided by the Reader into an object that will be stored * in the Model. It is passed the following parameters:{@link Ext.data.Field#defaultValue defaultValue}
.
// example of convert function
function fullName(v, record){
return record.name.last + ', ' + record.name.first;
}
function location(v, record){
return !record.city ? '' : (record.city + ', ' + record.state);
}
var Dude = Ext.regModel({
fields: [
{name: 'fullname', convert: fullName},
{name: 'firstname', mapping: 'name.first'},
{name: 'lastname', mapping: 'name.last'},
{name: 'city', defaultValue: 'homeless'},
'state',
{name: 'location', convert: location}
]
});
// create the data store
var store = new Ext.data.Store({
reader: {
type: 'json',
model: 'Dude',
idProperty: 'key',
root: 'daRoot',
totalProperty: 'total'
}
});
var myData = [
{ key: 1,
name: { first: 'Fat', last: 'Albert' }
// notice no city, state provided in data object
},
{ key: 2,
name: { first: 'Barney', last: 'Rubble' },
city: 'Bedrock', state: 'Stoneridge'
},
{ key: 3,
name: { first: 'Cliff', last: 'Claven' },
city: 'Boston', state: 'MA'
}
];
*
*/
/**
* @cfg {String} dateFormat
* (Optional) Used when converting received data into a Date when the {@link #type} is specified as "date"
.
A format string for the {@link Date#parseDate Ext.Date.parseDate} function, or "timestamp" if the * value provided by the Reader is a UNIX timestamp, or "time" if the value provided by the Reader is a * javascript millisecond timestamp. See {@link Date}
*/ dateFormat: null, /** * @cfg {Boolean} useNull *(Optional) Use when converting received data into a Number type (either int or float). If the value cannot be parsed, * null will be used if useNull is true, otherwise the value will be 0. Defaults to false */ useNull: false,
/** * @cfg {Mixed} defaultValue * (Optional) The default value used when a Model is being created by a {@link Ext.data.Reader Reader} * when the item referenced by the{@link Ext.data.Field#mapping mapping}
does not exist in the data
* object (i.e. undefined). (defaults to "")
*/
defaultValue: "",
/**
* @cfg {String/Number} mapping
* (Optional) A path expression for use by the {@link Ext.data.DataReader} implementation * that is creating the {@link Ext.data.Model Model} to extract the Field value from the data object. * If the path expression is the same as the field name, the mapping may be omitted.
*The form of the mapping expression depends on the Reader being used.
*If a more complex value extraction strategy is required, then configure the Field with a {@link #convert} * function. This is passed the whole row object, and may interrogate it in whatever way is necessary in order to * return the desired data.
*/ mapping: null, /** * @cfg {Function} sortType * (Optional) A function which converts a Field's value to a comparable value in order to ensure * correct sort ordering. Predefined functions are provided in {@link Ext.data.SortTypes}. A custom * sort example:
// current sort after sort we want
// +-+------+ +-+------+
// |1|First | |1|First |
// |2|Last | |3|Second|
// |3|Second| |2|Last |
// +-+------+ +-+------+
sortType: function(value) {
switch (value.toLowerCase()) // native toLowerCase():
{
case 'first': return 1;
case 'second': return 2;
default: return 3;
}
}
*
*/
sortType : null,
/**
* @cfg {String} sortDir
* (Optional) Initial direction to sort ("ASC"
or "DESC"
). Defaults to
* "ASC"
.
*/
sortDir : "ASC",
/**
* @cfg {Boolean} allowBlank
* @private
* (Optional) Used for validating a {@link Ext.data.Model model}, defaults to true
.
* An empty value here will cause {@link Ext.data.Model}.{@link Ext.data.Model#isValid isValid}
* to evaluate to false
.
*/
allowBlank : true
});