Source: src/main/javascript/oracle/oj/ojvalidation/RequiredValidator.js

/**
 * Copyright (c) 2008, 2013, Oracle and/or its affiliates.
 * All rights reserved.
 */

/**
 * Constructs a RequiredValidator that ensures that the value provided is not empty
 * @param {Object=} options an object literal used to provide an optional hint and error message.<p>
 * @param {string=} options.hint an optional hint text. There is no default hint provided by this 
 * validator.
 * @param {string=} options.messageSummary - an optional custom error message summarizing the 
 * error. When not present, the default message summary is the resource defined with the key 
 * <code class="prettyprint">oj-validator.required.summary</code>.<p>
 * Tokens: {label} - this token can be used to substitute the label of the component at runtime. </p>
 * <p>
 * Example:<br/>
 * "'{label}' Required"<br/>
 * </p>
 * @param {string=} options.messageDetail - a custom error message used for creating detail part 
 * of message, when the value provided is empty. When not present, the default message detail is the 
 * resource defined with the key <code class="prettyprint">oj-validator.required.detail</code>.
 * <p>Tokens: {label} - this token can be used to substitute the label of the component at runtime.</p>
 * <p>
 * Example:<br/>
 * "A value is required for the field '{label}'."<br/>
 * </p>
 * 
 * @export
 * @constructor
 * @since 0.6
 * 
 */
oj.RequiredValidator = function(options) 
{
  this.Init(options);
};

// Subclass from oj.Object or oj.Validator. It does not matter
oj.Object.createSubclass(oj.RequiredValidator, oj.Validator, "oj.RequiredValidator");

// key to access required validator specific resources in the bundle 
oj.RequiredValidator._BUNDLE_KEY_DETAIL = "oj-validator.required.detail";
oj.RequiredValidator._BUNDLE_KEY_SUMMARY = "oj-validator.required.summary";

/**
 * Initializes validator instance with the set options
 * @param {Object=} options
 * @memberof oj.RequiredValidator
 * @instance
 * @export
 */
oj.RequiredValidator.prototype.Init = function(options) 
{
  oj.RequiredValidator.superclass.Init.call(this);
  this._options = options;
};

/**
 * Validates value to be non-empty
 * 
 * @param {Object|string|number} value that is being validated 
 * @returns {boolean} true if validation was was successful the value is non-empty
 * 
 * @throws {Error} when fails required-ness check
 * @memberof oj.RequiredValidator
 * @instance
 * @export
 */
oj.RequiredValidator.prototype.validate = function(value)
{
  var localizedDetail, localizedSummary, detail, summary, params = {}, label = "";
  // checks for empty arrays and String. Objects are considered non-null.
  // Need to specifically test for if value is 0 first if number is passed on.
  if ((typeof value === "number" && value === 0) || (value && value.length !== 0))
  {
    return true;
  }
  else
  {
    if (this._options)
    {
      // we have deprecated support for message param and instead use messageDetail.
      detail = this._options['messageDetail'] || this._options['message'] || null;
      summary = this._options['messageSummary'] || null;
      label = this._options['label'] || "";
    }
    params = {'label': label};
    localizedSummary = (summary) ? oj.Translations.applyParameters(summary, params) :
            oj.Translations.getTranslatedString(this._getSummaryKey(), params);
    localizedDetail = (detail) ? 
    oj.Translations.applyParameters(detail, params) : 
    oj.Translations.getTranslatedString(this._getDetailKey(), params);
    
    throw new oj.ValidatorError(localizedSummary, localizedDetail);
  }

};

/**
 * A message to be used as hint, when giving a hint on the expected pattern. There is no default 
 * hint for this property.
 * 
 * @returns {String|string|null} a hint message or null if no hint is available in the options
 * @memberof oj.RequiredValidator
 * @instance
 * @export
 */
oj.RequiredValidator.prototype.getHint = function()
{
  var hint = "";
  if (this._options && (this._options['hint']))
  {
    hint = oj.Translations.getTranslatedString(this._options['hint']);
  }
  
  return hint;
};

oj.RequiredValidator.prototype._getSummaryKey = function ()
{
  return oj.RequiredValidator._BUNDLE_KEY_SUMMARY;
};

oj.RequiredValidator.prototype._getDetailKey = function ()
{
  return oj.RequiredValidator._BUNDLE_KEY_DETAIL;
};