user/src/com/google/gwt/user/client/ui/Label.java

/*
 * 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.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.HasAllMouseHandlers;
import com.google.gwt.event.dom.client.HasClickHandlers;
import com.google.gwt.event.dom.client.MouseDownEvent;
import com.google.gwt.event.dom.client.MouseDownHandler;
import com.google.gwt.event.dom.client.MouseMoveEvent;
import com.google.gwt.event.dom.client.MouseMoveHandler;
import com.google.gwt.event.dom.client.MouseOutEvent;
import com.google.gwt.event.dom.client.MouseOutHandler;
import com.google.gwt.event.dom.client.MouseOverEvent;
import com.google.gwt.event.dom.client.MouseOverHandler;
import com.google.gwt.event.dom.client.MouseUpEvent;
import com.google.gwt.event.dom.client.MouseUpHandler;
import com.google.gwt.event.dom.client.MouseWheelEvent;
import com.google.gwt.event.dom.client.MouseWheelHandler;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.i18n.client.BidiUtils;
import com.google.gwt.i18n.client.HasDirection;

/**
 * A widget that contains arbitrary text, <i>not</i> interpreted as HTML.
 * 
 * This widget uses a &lt;div&gt; element, causing it to be displayed with block
 * layout.
 * 
 * <h3>CSS Style Rules</h3>
 * <ul class='css'>
 * <li>.gwt-Label { }</li>
 * </ul>
 * 
 * <p>
 * <h3>Example</h3>
 * {@example com.google.gwt.examples.HTMLExample}
 * </p>
 */
@SuppressWarnings("deprecation")
public class Label extends Widget implements HasHorizontalAlignment, HasText,
    HasWordWrap, HasDirection, HasClickHandlers, SourcesClickEvents,
    SourcesMouseEvents, HasAllMouseHandlers {

  /**
   * Creates a Label widget that wraps an existing &lt;div&gt; or &lt;span&gt;
   * 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 Label wrap(Element element) {
    // Assert that the element is attached.
    assert Document.get().getBody().isOrHasChild(element);

    Label label = new Label(element);

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

    return label;
  }

  private HorizontalAlignmentConstant horzAlign;

  /**
   * Creates an empty label.
   */
  public Label() {
    setElement(Document.get().createDivElement());
    setStyleName("gwt-Label");
  }

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

  /**
   * Creates a label with the specified text.
   * 
   * @param text the new label's text
   * @param wordWrap <code>false</code> to disable word wrapping
   */
  public Label(String text, boolean wordWrap) {
    this(text);
    setWordWrap(wordWrap);
  }

  /**
   * This constructor may be used by subclasses to explicitly use an existing
   * element. This element must be either a &lt;div&gt; or &lt;span&gt; element.
   * 
   * @param element the element to be used
   */
  protected Label(Element element) {
    setElement(element);
    assert element.getTagName().equalsIgnoreCase("div")
        || element.getTagName().equalsIgnoreCase("span");
  }

  public HandlerRegistration addClickHandler(ClickHandler handler) {
    return addDomHandler(handler, ClickEvent.getType());
  }

  /**
   * @deprecated Use {@link #addClickHandler} instead
   */
  @Deprecated
  public void addClickListener(ClickListener listener) {
    ListenerWrapper.WrappedClickListener.add(this, listener);
  }

  public HandlerRegistration addMouseDownHandler(MouseDownHandler handler) {
    return addDomHandler(handler, MouseDownEvent.getType());
  }

  /**
   * @deprecated Use {@link #addMouseOverHandler} {@link
   * #addMouseMoveHandler}, {@link #addMouseDownHandler}, {@link
   * #addMouseUpHandler} and {@link #addMouseOutHandler} instead
   */
  @Deprecated
  public void addMouseListener(MouseListener listener) {
    ListenerWrapper.WrappedMouseListener.add(this, listener);
  }

  public HandlerRegistration addMouseMoveHandler(MouseMoveHandler handler) {
    return addDomHandler(handler, MouseMoveEvent.getType());
  }

  public HandlerRegistration addMouseOutHandler(MouseOutHandler handler) {
    return addDomHandler(handler, MouseOutEvent.getType());
  }

  public HandlerRegistration addMouseOverHandler(MouseOverHandler handler) {
    return addDomHandler(handler, MouseOverEvent.getType());
  }

  public HandlerRegistration addMouseUpHandler(MouseUpHandler handler) {
    return addDomHandler(handler, MouseUpEvent.getType());
  }

  public HandlerRegistration addMouseWheelHandler(MouseWheelHandler handler) {
    return addDomHandler(handler, MouseWheelEvent.getType());
  }

  /**
   * @deprecated Use {@link #addMouseWheelHandler} instead
   */
  @Deprecated
  public void addMouseWheelListener(MouseWheelListener listener) {
    ListenerWrapper.WrappedMouseWheelListener.add(this, listener);
  }

  public Direction getDirection() {
    return BidiUtils.getDirectionOnElement(getElement());
  }

  public HorizontalAlignmentConstant getHorizontalAlignment() {
    return horzAlign;
  }

  public String getText() {
    return getElement().getInnerText();
  }

  public boolean getWordWrap() {
    return !getElement().getStyle().getProperty("whiteSpace").equals("nowrap");
  }

  /**
   * @deprecated Use the {@link HandlerRegistration#removeHandler} method on 
   * the object returned by {@link #addClickHandler} instead
   */
  @Deprecated
  public void removeClickListener(ClickListener listener) {
    ListenerWrapper.WrappedClickListener.remove(this, listener);
  }

  /**
   * @deprecated Use the {@link HandlerRegistration#removeHandler}
   * method on the object returned by an add*Handler method instead
   */
  @Deprecated
  public void removeMouseListener(MouseListener listener) {
    ListenerWrapper.WrappedMouseListener.remove(this, listener);
  }

  /**
   * @deprecated Use the {@link HandlerRegistration#removeHandler}
   * method on the object returned by {@link #addMouseWheelHandler} instead
   */
  @Deprecated
  public void removeMouseWheelListener(MouseWheelListener listener) {
    ListenerWrapper.WrappedMouseWheelListener.remove(this, listener);
  }

  public void setDirection(Direction direction) {
    BidiUtils.setDirectionOnElement(getElement(), direction);
  }

  public void setHorizontalAlignment(HorizontalAlignmentConstant align) {
    horzAlign = align;
    getElement().getStyle().setProperty("textAlign", align.getTextAlignString());
  }

  public void setText(String text) {
    getElement().setInnerText(text);
  }

  public void setWordWrap(boolean wrap) {
    getElement().getStyle().setProperty("whiteSpace",
        wrap ? "normal" : "nowrap");
  }
}