/*
 * Copyright 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.user.client.ui;

import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;

import com.google.gwt.i18n.shared.DirectionEstimator;

/**
 * A widget that contains arbitrary text, <i>not</i> interpreted as HTML.
 *
 * This widget uses a <span> element, causing it to be displayed with
 * inline layout.
 *
 * <p>
 * <h3>Built-in Bidi Text Support</h3>
 * This widget is capable of automatically adjusting its direction according to
 * its content. This feature is controlled by {@link #setDirectionEstimator} or
 * passing a DirectionEstimator parameter to the constructor, and is off by
 * default.
 * </p>
 *
 * <h3>CSS Style Rules</h3>
 * <ul class='css'>
 * <li>.gwt-InlineLabel { }</li>
 * </ul>
 */
public class InlineLabel extends Label {

  /**
   * Creates a InlineLabel widget that wraps an existing <div> or
   * <span> element.
   *
   * This element must already be attached to the document. If the element is
   * removed from the document, you must call
   * {@link RootPanel#detachNow(Widget)}.
   *
   * @param element the element to be wrapped
   */
  public static InlineLabel wrap(Element element) {
    // Assert that the element is attached.
    assert Document.get().getBody().isOrHasChild(element);

    InlineLabel label = new InlineLabel(element);

    // Mark it attached and remember it for cleanup.
    label.onAttach();
    RootPanel.detachOnWindowClose(label);

    return label;
  }

  /**
   * Creates an empty label.
   */
  public InlineLabel() {
    super(Document.get().createSpanElement());
    setStyleName("gwt-InlineLabel");
  }

  /**
   * Creates a label with the specified text.
   *
   * @param text the new label's text
   */
  public InlineLabel(String text) {
    this();
    setText(text);
  }

  /**
   * Creates a label with the specified text and direction.
   *
   * @param text the new label's text
   * @param dir the text's direction. Note: {@code Direction.DEFAULT} means
   *        direction should be inherited from the widget's parent element.
   */
  public InlineLabel(String text, Direction dir) {
    this();
    setText(text, dir);
  }

  /**
   * Creates a label with the specified text and a default direction estimator.
   *
   * @param text the new label's text
   * @param directionEstimator A DirectionEstimator object used for automatic
   *          direction adjustment. For convenience,
   *          {@link Label#DEFAULT_DIRECTION_ESTIMATOR} can be used.
   */
  public InlineLabel(String text, DirectionEstimator directionEstimator) {
    this();
    setDirectionEstimator(directionEstimator);
    setText(text);
  }
  
  /**
   * This constructor may be used by subclasses to explicitly use an existing
   * element. This element must be either a <div> <span> element.
   *
   * @param element the element to be used
   */
  protected InlineLabel(Element element) {
    // super(element) also asserts that element is either a <div> or
    // <span>.
    super(element);
  }
}