Java Code Examples for com.google.gwt.dom.client.Element#getFirstChild()

/**
  * Add back in the impl nodelets of the children.
  *
  * Override this to provide specific functionality as needed. For example,
  * ensuring certain children live in certain specific locations of the
  * doodad's dom.
  */
protected void reattachImplChildren() {
  ContentView renderedContent = getRenderedContentView();
  Element container = getContainerNodelet();
  if (container != null) {
    while (container.getFirstChild() != null) {
      container.getFirstChild().removeFromParent();
    }
    for (ContentNode node = renderedContent.getFirstChild(this); node != null;
        node = renderedContent.getNextSibling(node)) {
      container.appendChild(node.getImplNodelet());
    }
  } else {
    EditorStaticDeps.logger.error().log(
        "You need to override this method for your doodad: " + tagName);
  }
}
 

private void deletify(Element element) {
  if (element == null) {
    // NOTE(danilatos): Not handling the case where the content element
    // is transparent w.r.t. the rendered view, but has visible children.
    return;
  }

  DiffManager.styleElement(element, DiffType.DELETE,
      operationCtx.getCreator() != null ? operationCtx.getCreator().getAddress() : "",
      operationCtx.getHashedVersion().getVersion(), operationCtx.getTimestamp());
  DomHelper.makeUnselectable(element);

  for (Node n = element.getFirstChild(); n != null; n = n.getNextSibling()) {
    if (!DomHelper.isTextNode(n)) {
      deletify(n.<Element> cast());
    }
  }
}
 

private void deletify(Element element) {
  if (element == null) {
    // NOTE(danilatos): Not handling the case where the content element
    // is transparent w.r.t. the rendered view, but has visible children.
    return;
  }

  DiffManager.styleElement(element, DiffType.DELETE);
  DomHelper.makeUnselectable(element);

  for (Node n = element.getFirstChild(); n != null; n = n.getNextSibling()) {
    if (!DomHelper.isTextNode(n)) {
      deletify(n.<Element> cast());
    }
  }
}
 

/**
  * Add back in the impl nodelets of the children.
  *
  * Override this to provide specific functionality as needed. For example,
  * ensuring certain children live in certain specific locations of the
  * doodad's dom.
  */
protected void reattachImplChildren() {
  ContentView renderedContent = getRenderedContentView();
  Element container = getContainerNodelet();
  if (container != null) {
    while (container.getFirstChild() != null) {
      container.getFirstChild().removeFromParent();
    }
    for (ContentNode node = renderedContent.getFirstChild(this); node != null;
        node = renderedContent.getNextSibling(node)) {
      container.appendChild(node.getImplNodelet());
    }
  } else {
    EditorStaticDeps.logger.error().log(
        "You need to override this method for your doodad: " + tagName);
  }
}
 

/**
 * Remove the given node (leaving its children in the dom) if
 * it does not correspond to a wrapper ContentNode
 * @param node
 * @return true if the node was removed, false if not.
 */
private boolean maybeStrip(Node node) {
  if (node == null || DomHelper.isTextNode(node)) return false;

  Element element = node.cast();
  if (!NodeManager.hasBackReference(element)) {
    Node n;
    while ((n = element.getFirstChild()) != null) {
      element.getParentNode().insertBefore(n, element);
    }
    element.removeFromParent();
    return true;
  }
  return false;
}
 

/**
 * {@inheritDoc}
 */
@Override
public void onRemovingChild(Node child, Element paragraph) {
  Node first = paragraph.getFirstChild();
  BRElement spacer = getSpacer(paragraph);
  if (first == null) {
    appendSpacer(paragraph);
  } else if (first != spacer) {
    spacer.removeFromParent();
  }
}
 

/**
 * Mark implementation elements that aren't transparent as part of a
 * a complex implementation structure.
 *
 * @param element
 */
public static void walkImpl(Element element) {
  for (Node n = element.getFirstChild(); n != null;) {
    if (DomHelper.isTextNode(n)) {
      n = n.getNextSibling();
    } else {
      Element e = n.cast();
      if (!NodeManager.isTransparent(e)) {
        e.setPropertyBoolean(COMPLEX_IMPLEMENTATION_MARKER, true);
      }
      walkImpl(e);
      n = n.getNextSibling();
    }
  }
}
 

/**
 * Remove the given node (leaving its children in the dom) if
 * it does not correspond to a wrapper ContentNode
 * @param node
 * @return true if the node was removed, false if not.
 */
private boolean maybeStrip(Node node) {
  if (node == null || DomHelper.isTextNode(node)) return false;

  Element element = node.cast();
  if (!NodeManager.hasBackReference(element)) {
    Node n;
    while ((n = element.getFirstChild()) != null) {
      element.getParentNode().insertBefore(n, element);
    }
    element.removeFromParent();
    return true;
  }
  return false;
}
 

/**
 * Mark implementation elements that aren't transparent as part of a
 * a complex implementation structure.
 *
 * @param element
 */
public static void walkImpl(Element element) {
  for (Node n = element.getFirstChild(); n != null;) {
    if (DomHelper.isTextNode(n)) {
      n = n.getNextSibling();
    } else {
      Element e = n.cast();
      if (!NodeManager.isTransparent(e)) {
        e.setPropertyBoolean(COMPLEX_IMPLEMENTATION_MARKER, true);
      }
      walkImpl(e);
      n = n.getNextSibling();
    }
  }
}
 

/**
 * {@inheritDoc}
 */
@Override
public void onRemovingChild(Node child, Element paragraph) {
  Node first = paragraph.getFirstChild();
  BRElement spacer = getSpacer(paragraph);
  if (first == null) {
    appendSpacer(paragraph);
  } else if (first != spacer) {
    spacer.removeFromParent();
  }
}
 

private void updateCheckboxDom(ContentElement checkbox, boolean isChecked) {
  Element implNodelet = checkbox.getImplNodelet();
  InputElement checkboxElem = (InputElement) implNodelet.getFirstChild();
  checkboxElem.setChecked(isChecked);
}
 

/**
 * @param n Node to pretty print
 * @param selection Selection to mark in pretty print
 * @param indent Indentation level to print with.
 * @param multiLine True if output should be multi-line
 * @return A pretty-print HTML string (with '<' and '>' already escaped)
 */
private static String print(Node n, PointRange<Node> selection, int indent, boolean multiLine) {

  // Inspect selection's relevance to this element
  boolean collapsed = selection != null && selection.isCollapsed();
  boolean printStartMarker =
      selection != null && selection.getFirst().getContainer().equals(n);
  boolean printEndMarker =
      selection != null && !collapsed && selection.getSecond().getContainer().equals(n);
  String startMarker =
      printStartMarker ? (collapsed ? "|" : "[") : "";
  String endMarker = printEndMarker ? "]" : "";
  if (DomHelper.isTextNode(n)) {
    // Print text node as 'value'
    String value = displayWhitespace(n.getNodeValue());
    int startOffset = printStartMarker ? selection.getFirst().getTextOffset() : 0;
    int endOffset = printEndMarker ? selection.getSecond().getTextOffset() : value.length();
    String ret = "'" + value.substring(0, startOffset)
        + startMarker
        + value.substring(startOffset, endOffset)
        + endMarker
        + value.substring(endOffset, value.length())
        + "'" ;
    return multiLine ? StringUtil.xmlEscape(ret) : ret;
  } else {
    Element e = n.cast();
    if (e.getChildCount() == 0) {
      // Print child-less element as self-closing tag
      return startTag(e, true, multiLine);
    } else {
      boolean singleLineHtml = multiLine &&
        (e.getChildCount() == 1 &&
          e.getFirstChild()
          .getChildCount() == 0);
      // Print element w/ children. One line each for start tag, child, end tag
      String pretty = startTag(e, false, multiLine);
      Node child = e.getFirstChild();
      Node startNodeAfter = selection.getFirst().getNodeAfter();
      Node endNodeAfter = selection.getSecond().getNodeAfter();
      while (child != null) {
        pretty += (multiLine && !singleLineHtml ? newLine(indent + 1) : "")
          + (printStartMarker && child.equals(startNodeAfter) ? startMarker : "")
          + (printEndMarker && child.equals(endNodeAfter) ? endMarker : "")
          + print(child, selection, indent + 1, multiLine);
        child = child.getNextSibling();
      }
      if (printEndMarker && endNodeAfter == null) {
        pretty += endMarker;
      }
      return pretty + (multiLine  && !singleLineHtml ? newLine(indent) : "")
          + endTag(e, multiLine);
    }
  }
}
 

@SuppressWarnings("unused") // NOTE(user): may be used later
private Point<Node> linearSearchForRange(JsTextRangeIE target, Element parent) {
  try {
    // We'll iterate through the parent's children while moving
    // a new collapsed range, attempt, through the points before
    // each child.
    Node child = parent.getFirstChild();
    // Start attempt at beginning of parent
    JsTextRangeIE attempt = JsTextRangeIE.create().moveToElementText(parent).collapse(true);
    while (child != null) {
      // Treat text node children separately
      if (DomHelper.isTextNode(child)) {
        // Move attempt to end of the text node
        int len = child.<Text> cast().getLength();
        attempt.move(character, len);
        // Test if attempt is now at or past target
        if (attempt.compareEndPoints(StartToStart, target) >= 0) {
          // Target is in this text node. Compute the offset by creating a new
          // text range from target to attempt and measuring the length of the
          // text in that range
          JsTextRangeIE dup =
              attempt.duplicate().setEndPoint(StartToStart, target)
                  .setEndPoint(EndToEnd, attempt);
          return Point.inText(child, len - dup.getText().length());
        }
      } else {
        // Child is an element. Move attempt before child, and test
        // if attempt is at or past range
        attempt.moveToElementText(child.<Element> cast()).collapse(true);
        if (attempt.compareEndPoints(StartToStart, target) >= 0) {
          // Return the point before child
          return Point.inElement(parent, child);
        } else {
          // Move attempt past child
          // We use our inline, non-empty marker element to do this.
          // We also leave it in the dom for max reliability until it's needed
          // later, or gets taken out in the finally clause at the end of this method
          child.getParentNode().insertAfter(setter, child);
          // skip pass the setter.
          child = child.getNextSibling();

          attempt.moveToElementText(setter).collapse(false);
        }
      }
      // Move to next child
      child = child.getNextSibling();
    }

    // We didn't find target before or in children; return point at end of
    // parent
    return Point.<Node> end(parent);
    // TODO(user): look out for other corner cases
    // TODO(user, danilatos): implement danilatos' optimisation of first
    // checking inside the last text node that held a point.
    // TODO(user): consider binary rather than linear search for target
    // TODO(user): does this handle the end of a <p>ab[</p><p>]cd</p> type
    // selection?
    // TODO(danilatos): When someone selects the "newline" at the edge
    // of a <p>, e.g. <p>abc[</p><p>]def</p> (where [ ] is the sel)
    // this reports the selection still as <p>abc[]</p><p>def</p>
    // It appears to be a detectable scenario when the first line
    // is not empty, but it isn't when both lines are empty. However,
    // I did notice a difference before when I was experimenting with
    // getBookmark(), so perhaps we could resort to tricks with checking
    // bookmarks around paragraph boundaries...
    // TODO(user, danilatos): consider making attempt and other ranges
    // used here static singletons
  } finally {
    setter.removeFromParent();
  }
}
 

/**
 * Remove all children from an element
 * @param element
 */
public static void emptyElement(Element element) {
  while (element.getFirstChild() != null) {
    element.removeChild(element.getFirstChild());
  }
}
 

private void updateCheckboxDom(ContentElement checkbox, boolean isChecked) {
  Element implNodelet = checkbox.getImplNodelet();
  InputElement checkboxElem = (InputElement) implNodelet.getFirstChild();
  checkboxElem.setChecked(isChecked);
}
 

/**
 * @param n Node to pretty print
 * @param selection Selection to mark in pretty print
 * @param indent Indentation level to print with.
 * @param multiLine True if output should be multi-line
 * @return A pretty-print HTML string (with '<' and '>' already escaped)
 */
private static String print(Node n, PointRange<Node> selection, int indent, boolean multiLine) {

  // Inspect selection's relevance to this element
  boolean collapsed = selection != null && selection.isCollapsed();
  boolean printStartMarker =
      selection != null && selection.getFirst().getContainer().equals(n);
  boolean printEndMarker =
      selection != null && !collapsed && selection.getSecond().getContainer().equals(n);
  String startMarker =
      printStartMarker ? (collapsed ? "|" : "[") : "";
  String endMarker = printEndMarker ? "]" : "";
  if (DomHelper.isTextNode(n)) {
    // Print text node as 'value'
    String value = displayWhitespace(n.getNodeValue());
    int startOffset = printStartMarker ? selection.getFirst().getTextOffset() : 0;
    int endOffset = printEndMarker ? selection.getSecond().getTextOffset() : value.length();
    String ret = "'" + value.substring(0, startOffset)
        + startMarker
        + value.substring(startOffset, endOffset)
        + endMarker
        + value.substring(endOffset, value.length())
        + "'" ;
    return multiLine ? StringUtil.xmlEscape(ret) : ret;
  } else {
    Element e = n.cast();
    if (e.getChildCount() == 0) {
      // Print child-less element as self-closing tag
      return startTag(e, true, multiLine);
    } else {
      boolean singleLineHtml = multiLine &&
        (e.getChildCount() == 1 &&
          e.getFirstChild()
          .getChildCount() == 0);
      // Print element w/ children. One line each for start tag, child, end tag
      String pretty = startTag(e, false, multiLine);
      Node child = e.getFirstChild();
      Node startNodeAfter = selection.getFirst().getNodeAfter();
      Node endNodeAfter = selection.getSecond().getNodeAfter();
      while (child != null) {
        pretty += (multiLine && !singleLineHtml ? newLine(indent + 1) : "")
          + (printStartMarker && child.equals(startNodeAfter) ? startMarker : "")
          + (printEndMarker && child.equals(endNodeAfter) ? endMarker : "")
          + print(child, selection, indent + 1, multiLine);
        child = child.getNextSibling();
      }
      if (printEndMarker && endNodeAfter == null) {
        pretty += endMarker;
      }
      return pretty + (multiLine  && !singleLineHtml ? newLine(indent) : "")
          + endTag(e, multiLine);
    }
  }
}
 

@SuppressWarnings("unused") // NOTE(user): may be used later
private Point<Node> linearSearchForRange(JsTextRangeIE target, Element parent) {
  try {
    // We'll iterate through the parent's children while moving
    // a new collapsed range, attempt, through the points before
    // each child.
    Node child = parent.getFirstChild();
    // Start attempt at beginning of parent
    JsTextRangeIE attempt = JsTextRangeIE.create().moveToElementText(parent).collapse(true);
    while (child != null) {
      // Treat text node children separately
      if (DomHelper.isTextNode(child)) {
        // Move attempt to end of the text node
        int len = child.<Text> cast().getLength();
        attempt.move(character, len);
        // Test if attempt is now at or past target
        if (attempt.compareEndPoints(StartToStart, target) >= 0) {
          // Target is in this text node. Compute the offset by creating a new
          // text range from target to attempt and measuring the length of the
          // text in that range
          JsTextRangeIE dup =
              attempt.duplicate().setEndPoint(StartToStart, target)
                  .setEndPoint(EndToEnd, attempt);
          return Point.inText(child, len - dup.getText().length());
        }
      } else {
        // Child is an element. Move attempt before child, and test
        // if attempt is at or past range
        attempt.moveToElementText(child.<Element> cast()).collapse(true);
        if (attempt.compareEndPoints(StartToStart, target) >= 0) {
          // Return the point before child
          return Point.inElement(parent, child);
        } else {
          // Move attempt past child
          // We use our inline, non-empty marker element to do this.
          // We also leave it in the dom for max reliability until it's needed
          // later, or gets taken out in the finally clause at the end of this method
          child.getParentNode().insertAfter(setter, child);
          // skip pass the setter.
          child = child.getNextSibling();

          attempt.moveToElementText(setter).collapse(false);
        }
      }
      // Move to next child
      child = child.getNextSibling();
    }

    // We didn't find target before or in children; return point at end of
    // parent
    return Point.<Node> end(parent);
    // TODO(user): look out for other corner cases
    // TODO(user, danilatos): implement danilatos' optimisation of first
    // checking inside the last text node that held a point.
    // TODO(user): consider binary rather than linear search for target
    // TODO(user): does this handle the end of a <p>ab[</p><p>]cd</p> type
    // selection?
    // TODO(danilatos): When someone selects the "newline" at the edge
    // of a <p>, e.g. <p>abc[</p><p>]def</p> (where [ ] is the sel)
    // this reports the selection still as <p>abc[]</p><p>def</p>
    // It appears to be a detectable scenario when the first line
    // is not empty, but it isn't when both lines are empty. However,
    // I did notice a difference before when I was experimenting with
    // getBookmark(), so perhaps we could resort to tricks with checking
    // bookmarks around paragraph boundaries...
    // TODO(user, danilatos): consider making attempt and other ranges
    // used here static singletons
  } finally {
    setter.removeFromParent();
  }
}
 

/**
 * Remove all children from an element
 * @param element
 */
public static void emptyElement(Element element) {
  while (element.getFirstChild() != null) {
    element.removeChild(element.getFirstChild());
  }
}