    /**
     * @author Ed Spencer
     * @class Ext.data.Errors
     * @extends Ext.util.MixedCollection
     *
     * <p>Wraps a collection of validation error responses and provides convenient functions for
     * accessing and errors for specific fields.</p>
     *
     * <p>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:</p>
     *
    <pre><code>
    //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'}]
    </code></pre>
     */
    Ext.define('Ext.data.Errors', {
        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;
        }
    });