/**
 * @author Ed Spencer
 * @class Ext.data.Errors
 * @extends Ext.util.MixedCollection
 * 
 * 
Wraps a collection of validation error responses and provides convenient functions for
 * accessing and errors for specific fields.
 * 
 * 
Usually this class does not need to be instantiated directly - instances are instead created
 * automatically when {@link Ext.data.Model#validate validate} on a model instance:
 * 

//validate some existing model instance - in this case it returned 2 failures messages
var errors = myModel.validate();

errors.isValid(); //false

errors.length; //2
errors.getByField('name');  // [{field: 'name',  error: 'must be present'}]
errors.getByField('title'); // [{field: 'title', error: 'is too short'}]

 */
Ext.data.Errors = Ext.extend(Ext.util.MixedCollection, {
    
/**
     * Returns true if there are no errors in the collection
     * @return {Boolean} 
     */
    isValid: function() {
        return this.length == 0;
    },
    
    
/**
     * Returns all of the errors for the given field
     * @param {String} fieldName The field to get errors for
     * @return {Array} All errors for the given field
     */
    getByField: function(fieldName) {
        var errors = [],
            error, field, i;
            
        for (i = 0; i < this.length; i++) {
            error = this.items[i];
            
            if (error.field == fieldName) {
                errors.push(error);
            }
        }
        
        return errors;
    }
});