org.enhydra.apache.xerces.dom.RangeImpl Maven / Gradle / Ivy
/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*4dorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, International
* Business Machines, Inc., http://www.apache.org. For more
* information on the Apache Software Foundation, please see
* Please see the API documentation for the interface classes
* and use the interfaces in your client programs.
*/
public class RangeImpl implements Range {
//
// Constants
//
//
// Data
//
DocumentImpl fDocument;
Node fStartContainer;
Node fEndContainer;
int fStartOffset;
int fEndOffset;
boolean fIsCollapsed;
boolean fDetach = false;
Node fInsertNode = null;
Node fDeleteNode = null;
Node fSplitNode = null;
/** The constructor. Clients must use DocumentRange.createRange(),
* because it registers the Range with the document, so it can
* be fixed-up.
*/
public RangeImpl(DocumentImpl document) {
fDocument = document;
fStartContainer = document;
fEndContainer = document;
fStartOffset = 0;
fEndOffset = 0;
fDetach = false;
}
public Node getStartContainer() {
return fStartContainer;
}
public int getStartOffset() {
return fStartOffset;
}
public Node getEndContainer() {
return fEndContainer;
}
public int getEndOffset() {
return fEndOffset;
}
public boolean getCollapsed() {
return (fStartContainer == fEndContainer
&& fStartOffset == fEndOffset);
}
public Node getCommonAncestorContainer(){
Vector startV = new Vector();
Node node;
for (node=fStartContainer; node != null;
node=node.getParentNode())
{
startV.addElement(node);
}
Vector endV = new Vector();
for (node=fEndContainer; node != null;
node=node.getParentNode())
{
endV.addElement(node);
}
int s = startV.size()-1;
int e = endV.size()-1;
Object result = null;
while (s>=0 && e>=0) {
if (startV.elementAt(s) == endV.elementAt(e)) {
result = startV.elementAt(s);
} else {
break;
}
--s;
--e;
}
return (Node)result;
}
public void setStart(Node refNode, int offset)
throws RangeException, DOMException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !isLegalContainer(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
checkIndex(refNode, offset);
fStartContainer = refNode;
fStartOffset = offset;
}
public void setEnd(Node refNode, int offset)
throws RangeException, DOMException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !isLegalContainer(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
checkIndex(refNode, offset);
fEndContainer = refNode;
fEndOffset = offset;
}
public void setStartBefore(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !hasLegalRootContainer(refNode) ||
!isLegalContainedNode(refNode) )
{
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
fStartContainer = refNode.getParentNode();
int i = 0;
for (Node n = refNode; n!=null; n = n.getPreviousSibling()) {
i++;
}
fStartOffset = i-1;
}
public void setStartAfter(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !hasLegalRootContainer(refNode) ||
!isLegalContainedNode(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
fStartContainer = refNode.getParentNode();
int i = 0;
for (Node n = refNode; n!=null; n = n.getPreviousSibling()) {
i++;
}
fStartOffset = i;
}
public void setEndBefore(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !hasLegalRootContainer(refNode) ||
!isLegalContainedNode(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
fEndContainer = refNode.getParentNode();
int i = 0;
for (Node n = refNode; n!=null; n = n.getPreviousSibling()) {
i++;
}
fEndOffset = i-1;
}
public void setEndAfter(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !hasLegalRootContainer(refNode) ||
!isLegalContainedNode(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
fEndContainer = refNode.getParentNode();
int i = 0;
for (Node n = refNode; n!=null; n = n.getPreviousSibling()) {
i++;
}
fEndOffset = i;
}
public void collapse(boolean toStart) {
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if (toStart) {
fEndContainer = fStartContainer;
fEndOffset = fStartOffset;
} else {
fStartContainer = fEndContainer;
fStartOffset = fEndOffset;
}
}
public void selectNode(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !isLegalContainer( refNode.getParentNode() ) ||
!isLegalContainedNode( refNode ) ) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
Node parent = refNode.getParentNode();
if (parent != null ) // REVIST: what to do if it IS null?
{
fStartContainer = parent;
fEndContainer = parent;
int i = 0;
for (Node n = refNode; n!=null; n = n.getPreviousSibling()) {
i++;
}
fStartOffset = i-1;
fEndOffset = fStartOffset+1;
}
}
public void selectNodeContents(Node refNode)
throws RangeException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( !isLegalContainer(refNode)) {
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
fStartContainer = refNode;
fEndContainer = refNode;
Node first = refNode.getFirstChild();
fStartOffset = 0;
if (first == null) {
fEndOffset = 0;
} else {
int i = 0;
for (Node n = first; n!=null; n = n.getNextSibling()) {
i++;
}
fEndOffset = i;
}
}
public short compareBoundaryPoints(short how, Range sourceRange)
throws DOMException
{
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
Node endPointA;
Node endPointB;
int offsetA;
int offsetB;
if (how == START_TO_START) {
endPointA = sourceRange.getStartContainer();
endPointB = fStartContainer;
offsetA = sourceRange.getStartOffset();
offsetB = fStartOffset;
} else
if (how == START_TO_END) {
endPointA = sourceRange.getStartContainer();
endPointB = fEndContainer;
offsetA = sourceRange.getStartOffset();
offsetB = fEndOffset;
} else
if (how == END_TO_START) {
endPointA = sourceRange.getEndContainer();
endPointB = fStartContainer;
offsetA = sourceRange.getEndOffset();
offsetB = fStartOffset;
} else {
endPointA = sourceRange.getEndContainer();
endPointB = fEndContainer;
offsetA = sourceRange.getEndOffset();
offsetB = fEndOffset;
}
// The DOM Spec outlines four cases that need to be tested
// to compare two range boundary points:
// case 1: same container
// case 2: Child C of container A is ancestor of B
// case 3: Child C of container B is ancestor of A
// case 4: preorder traversal of context tree.
// case 1: same container
if (endPointA == endPointB) {
if (offsetA < offsetB) return 1;
if (offsetA == offsetB) return 0;
return -1;
}
// case 2: Child C of container A is ancestor of B
// This can be quickly tested by walking the parent chain of B
for ( Node c = endPointB, p = c.getParentNode();
p != null;
c = p, p = p.getParentNode())
{
if (p == endPointA) {
int index = indexOf(c, endPointA);
if (offsetA <= index) return 1;
return -1;
}
}
// case 3: Child C of container B is ancestor of A
// This can be quickly tested by walking the parent chain of A
for ( Node c = endPointA, p = c.getParentNode();
p != null;
c = p, p = p.getParentNode())
{
if (p == endPointB) {
int index = indexOf(c, endPointB);
if (index < offsetB) return 1;
return -1;
}
}
// case 4: preorder traversal of context tree.
// Instead of literally walking the context tree in pre-order,
// we use relative node depth walking which is usually faster
int depthDiff = 0;
for ( Node n = endPointA; n != null; n = n.getParentNode() )
depthDiff++;
for ( Node n = endPointB; n != null; n = n.getParentNode() )
depthDiff--;
while (depthDiff > 0) {
endPointA = endPointA.getParentNode();
depthDiff--;
}
while (depthDiff < 0) {
endPointB = endPointB.getParentNode();
depthDiff++;
}
for (Node pA = endPointA.getParentNode(),
pB = endPointB.getParentNode();
pA != pB;
pA = pA.getParentNode(), pB = pB.getParentNode() )
{
endPointA = pA;
endPointB = pB;
}
for ( Node n = endPointA.getNextSibling();
n != null;
n = n.getNextSibling() )
{
if (n == endPointB) {
return 1;
}
}
return -1;
}
public void deleteContents()
throws DOMException
{
traverseContents(DELETE_CONTENTS);
}
public DocumentFragment extractContents()
throws DOMException
{
return traverseContents(EXTRACT_CONTENTS);
}
public DocumentFragment cloneContents()
throws DOMException
{
return traverseContents(CLONE_CONTENTS);
}
public void insertNode(Node newNode)
throws DOMException, RangeException
{
if ( newNode == null ) return; //throw exception?
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
if ( fDocument != newNode.getOwnerDocument() ) {
throw new DOMException(DOMException.WRONG_DOCUMENT_ERR,"DOM004 Wrong document");
}
int type = newNode.getNodeType();
if (type == Node.ATTRIBUTE_NODE
|| type == Node.ENTITY_NODE
|| type == Node.NOTATION_NODE
|| type == Node.DOCUMENT_NODE)
{
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
Node cloneCurrent;
Node current;
int currentChildren = 0;
//boolean MULTIPLE_MODE = false;
if (fStartContainer.getNodeType() == Node.TEXT_NODE) {
Node parent = fStartContainer.getParentNode();
currentChildren = parent.getChildNodes().getLength(); //holds number of kids before insertion
// split text node: results is 3 nodes..
cloneCurrent = fStartContainer.cloneNode(false);
((TextImpl)cloneCurrent).setNodeValueInternal(
(cloneCurrent.getNodeValue()).substring(fStartOffset));
((TextImpl)fStartContainer).setNodeValueInternal(
(fStartContainer.getNodeValue()).substring(0,fStartOffset));
Node next = fStartContainer.getNextSibling();
if (next != null) {
if (parent != null) {
parent.insertBefore(newNode, next);
parent.insertBefore(cloneCurrent, next);
}
} else {
if (parent != null) {
parent.appendChild(newNode);
parent.appendChild(cloneCurrent);
}
}
//update ranges after the insertion
if ( fEndContainer == fStartContainer) {
fEndContainer = cloneCurrent; //endContainer is the new Node created
fEndOffset -= fStartOffset;
}
else if ( fEndContainer == parent ) { //endContainer was not a text Node.
//endOffset + = number_of_children_added
fEndOffset += (parent.getChildNodes().getLength() - currentChildren);
}
// signal other Ranges to update their start/end containers/offsets
signalSplitData(fStartContainer, cloneCurrent, fStartOffset);
} else { // ! TEXT_NODE
if ( fEndContainer == fStartContainer ) //need to remember number of kids
currentChildren= fEndContainer.getChildNodes().getLength();
current = fStartContainer.getFirstChild();
int i = 0;
for(i = 0; i < fStartOffset && current != null; i++) {
current=current.getNextSibling();
}
if (current != null) {
fStartContainer.insertBefore(newNode, current);
} else {
fStartContainer.appendChild(newNode);
}
//update fEndOffset. ex:
. Range(start;end): body,0; body,1
// insert :
. Range(start;end): body,0; body,2
if ( fEndContainer == fStartContainer ) { //update fEndOffset
fEndOffset += (fEndContainer.getChildNodes().getLength() - currentChildren);
}
}
}
public void surroundContents(Node newParent)
throws DOMException, RangeException
{
if (newParent==null) return;
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
int type = newParent.getNodeType();
if (type == Node.ATTRIBUTE_NODE
|| type == Node.ENTITY_NODE
|| type == Node.NOTATION_NODE
|| type == Node.DOCUMENT_TYPE_NODE
|| type == Node.DOCUMENT_NODE
|| type == Node.DOCUMENT_FRAGMENT_NODE)
{
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
Node root = getCommonAncestorContainer();
Node realStart = fStartContainer;
Node realEnd = fEndContainer;
if (fStartContainer.getNodeType() == Node.TEXT_NODE) {
realStart = fStartContainer.getParentNode();
}
if (fEndContainer.getNodeType() == Node.TEXT_NODE) {
realEnd = fEndContainer.getParentNode();
}
if (realStart != realEnd) {
throw new RangeExceptionImpl(
RangeException.BAD_BOUNDARYPOINTS_ERR,
"DOM013 Bad boundary points");
}
DocumentFragment frag = extractContents();
insertNode(newParent);
newParent.appendChild(frag);
selectNode(newParent);
}
public Range cloneRange(){
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
Range range = fDocument.createRange();
range.setStart(fStartContainer, fStartOffset);
range.setEnd(fEndContainer, fEndOffset);
return range;
}
public String toString(){
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
Node node = fStartContainer;
Node stopNode = fEndContainer;
StringBuffer sb = new StringBuffer();
if (fStartContainer.getNodeType() == Node.TEXT_NODE
|| fStartContainer.getNodeType() == Node.CDATA_SECTION_NODE
) {
if (fStartContainer == fEndContainer) {
sb.append(fStartContainer.getNodeValue().substring(fStartOffset, fEndOffset));
return sb.toString();
}
sb.append(fStartContainer.getNodeValue().substring(fStartOffset));
node=nextNode (node,true); //fEndContainer!=fStartContainer
}
else { //fStartContainer is not a TextNode
node=node.getFirstChild();
if (fStartOffset>0) { //find a first node within a range, specified by fStartOffset
int counter=0;
while (counter0 && stopNode!=null ){
--i;
stopNode = stopNode.getNextSibling();
}
if ( stopNode == null )
stopNode = nextNode( fEndContainer, false );
}
while (node != stopNode) { //look into all kids of the Range
if (node == null) break;
if (node.getNodeType() == Node.TEXT_NODE
|| node.getNodeType() == Node.CDATA_SECTION_NODE) {
sb.append(node.getNodeValue());
}
node = nextNode(node, true);
}
if (fEndContainer.getNodeType() == Node.TEXT_NODE
|| fEndContainer.getNodeType() == Node.CDATA_SECTION_NODE) {
sb.append(fEndContainer.getNodeValue().substring(0,fEndOffset));
}
return sb.toString();
}
public void detach() {
fDetach = true;
fDocument.removeRange(this);
}
//
// Mutation functions
//
/** Signal other Ranges to update their start/end
* containers/offsets. The data has already been split
* into the two Nodes.
*/
void signalSplitData(Node node, Node newNode, int offset) {
fSplitNode = node;
// notify document
fDocument.splitData(node, newNode, offset);
fSplitNode = null;
}
/** Fix up this Range if another Range has split a Text Node
* into 2 Nodes.
*/
void receiveSplitData(Node node, Node newNode, int offset) {
if (node == null || newNode == null) return;
if (fSplitNode == node) return;
if (node == fStartContainer
&& fStartContainer.getNodeType() == Node.TEXT_NODE) {
if (fStartOffset > offset) {
fStartOffset = fStartOffset - offset;
fStartContainer = newNode;
}
}
if (node == fEndContainer
&& fEndContainer.getNodeType() == Node.TEXT_NODE) {
if (fEndOffset > offset) {
fEndOffset = fEndOffset-offset;
fEndContainer = newNode;
}
}
}
/** This function inserts text into a Node and invokes
* a method to fix-up all other Ranges.
*/
void deleteData(CharacterData node, int offset, int count) {
fDeleteNode = node;
node.deleteData( offset, count);
fDeleteNode = null;
}
/** This function is called from DOM.
* The text has already beeen inserted.
* Fix-up any offsets.
*/
void receiveDeletedText(Node node, int offset, int count) {
if (node == null) return;
if (fDeleteNode == node) return;
if (node == fStartContainer
&& fStartContainer.getNodeType() == Node.TEXT_NODE) {
if (fStartOffset > offset+count) {
fStartOffset = offset+(fStartOffset-(offset+count));
} else
if (fStartOffset > offset) {
fStartOffset = offset;
}
}
if (node == fEndContainer
&& fEndContainer.getNodeType() == Node.TEXT_NODE) {
if (fEndOffset > offset+count) {
fEndOffset = offset+(fEndOffset-(offset+count));
} else
if (fEndOffset > offset) {
fEndOffset = offset;
}
}
}
/** This function inserts text into a Node and invokes
* a method to fix-up all other Ranges.
*/
void insertData(CharacterData node, int index, String insert) {
fInsertNode = node;
node.insertData( index, insert);
fInsertNode = null;
}
/** This function is called from DOM.
* The text has already beeen inserted.
* Fix-up any offsets.
*/
void receiveInsertedText(Node node, int index, int len) {
if (node == null) return;
if (fInsertNode == node) return;
if (node == fStartContainer
&& fStartContainer.getNodeType() == Node.TEXT_NODE) {
if (index < fStartOffset) {
fStartOffset = fStartOffset+len;
}
}
if (node == fEndContainer
&& fEndContainer.getNodeType() == Node.TEXT_NODE) {
if (index < fEndOffset) {
fEndOffset = fEndOffset+len;
}
}
}
/** This function is called from DOM.
* The text has already beeen replaced.
* Fix-up any offsets.
*/
void receiveReplacedText(Node node) {
if (node == null) return;
if (node == fStartContainer
&& fStartContainer.getNodeType() == Node.TEXT_NODE) {
fStartOffset = 0;
}
if (node == fEndContainer
&& fEndContainer.getNodeType() == Node.TEXT_NODE) {
fEndOffset = 0;
}
}
/** This function is called from the DOM.
* This node has already been inserted into the DOM.
* Fix-up any offsets.
*/
public void insertedNodeFromDOM(Node node) {
if (node == null) return;
if (fInsertNode == node) return;
Node parent = node.getParentNode();
if (parent == fStartContainer) {
int index = indexOf(node, fStartContainer);
if (index < fStartOffset) {
fStartOffset++;
}
}
if (parent == fEndContainer) {
int index = indexOf(node, fEndContainer);
if (index < fEndOffset) {
fEndOffset++;
}
}
}
/** This function is called within Range
* instead of Node.removeChild,
* so that the range can remember that it is actively
* removing this child.
*/
Node fRemoveChild = null;
Node removeChild(Node parent, Node child) {
fRemoveChild = child;
Node n = parent.removeChild(child);
fRemoveChild = null;
return n;
}
/** This function must be called by the DOM _BEFORE_
* a node is deleted, because at that time it is
* connected in the DOM tree, which we depend on.
*/
void removeNode(Node node) {
if (node == null) return;
if (fRemoveChild == node) return;
Node parent = node.getParentNode();
if (parent == fStartContainer) {
int index = indexOf(node, fStartContainer);
if (index < fStartOffset) {
fStartOffset--;
}
}
if (parent == fEndContainer) {
int index = indexOf(node, fEndContainer);
if (index < fEndOffset) {
fEndOffset--;
}
}
//startContainer or endContainer or both is/are the ancestor(s) of the Node to be deleted
if (parent != fStartContainer
|| parent != fEndContainer) {
if (isAncestorOf(node, fStartContainer)) {
fStartContainer = parent;
fStartOffset = indexOf( node, parent);
}
if (isAncestorOf(node, fEndContainer)) {
fEndContainer = parent;
fEndOffset = indexOf( node, parent);
}
}
}
//
// Utility functions.
//
// parameters for traverseContents(int)
//REVIST: use boolean, since there are only 2 now...
static final int EXTRACT_CONTENTS = 1;
static final int CLONE_CONTENTS = 2;
static final int DELETE_CONTENTS = 3;
/**
* This is the master routine invoked to visit the nodes
* selected by this range. For each such node, different
* actions are taken depending on the value of the
* how argument.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a document fragment containing the range's content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but sill
* produced cloned content in a document fragment
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes.
*
*
* @return Returns a document fragment containing any
* copied or extracted nodes. If the how
* parameter was DELETE_CONTENTS, the
* return value is null.
*/
private DocumentFragment traverseContents( int how )
throws DOMException
{
if (fStartContainer == null || fEndContainer == null) {
return null; // REVIST: Throw exception?
}
//Check for a detached range.
if( fDetach) {
throw new DOMException(
DOMException.INVALID_STATE_ERR,
"DOM011 Invalid state");
}
/*
Traversal is accomplished by first determining the
relationship between the endpoints of the range.
For each of four significant relationships, we will
delegate the traversal call to a method that
can make appropriate assumptions.
*/
// case 1: same container
if ( fStartContainer == fEndContainer )
return traverseSameContainer( how );
// case 2: Child C of start container is ancestor of end container
// This can be quickly tested by walking the parent chain of
// end container
int endContainerDepth = 0;
for ( Node c = fEndContainer, p = c.getParentNode();
p != null;
c = p, p = p.getParentNode())
{
if (p == fStartContainer)
return traverseCommonStartContainer( c, how );
++endContainerDepth;
}
// case 3: Child C of container B is ancestor of A
// This can be quickly tested by walking the parent chain of A
int startContainerDepth = 0;
for ( Node c = fStartContainer, p = c.getParentNode();
p != null;
c = p, p = p.getParentNode())
{
if (p == fEndContainer)
return traverseCommonEndContainer( c, how );
++startContainerDepth;
}
// case 4: There is a common ancestor container. Find the
// ancestor siblings that are children of that container.
int depthDiff = startContainerDepth - endContainerDepth;
Node startNode = fStartContainer;
while (depthDiff > 0) {
startNode = startNode.getParentNode();
depthDiff--;
}
Node endNode = fEndContainer;
while (depthDiff < 0) {
endNode = endNode.getParentNode();
depthDiff++;
}
// ascend the ancestor hierarchy until we have a common parent.
for( Node sp = startNode.getParentNode(), ep = endNode.getParentNode();
sp!=ep;
sp = sp.getParentNode(), ep = ep.getParentNode() )
{
startNode = sp;
endNode = ep;
}
return traverseCommonAncestors( startNode, endNode, how );
}
/**
* Visits the nodes selected by this range when we know
* a-priori that the start and end containers are the same.
* This method is invoked by the generic traverse
* method.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a document fragment containing the range's content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but sill
* produced cloned content in a document fragment
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes.
*
*
* @return Returns a document fragment containing any
* copied or extracted nodes. If the how
* parameter was DELETE_CONTENTS, the
* return value is null.
*/
private DocumentFragment traverseSameContainer( int how )
{
DocumentFragment frag = null;
if ( how!=DELETE_CONTENTS)
frag = fDocument.createDocumentFragment();
// If selection is empty, just return the fragment
if ( fStartOffset==fEndOffset )
return frag;
// Text node needs special case handling
if ( fStartContainer.getNodeType()==Node.TEXT_NODE )
{
// get the substring
String s = fStartContainer.getNodeValue();
String sub = s.substring( fStartOffset, fEndOffset );
// set the original text node to its new value
if ( how != CLONE_CONTENTS )
{
fStartContainer.setNodeValue(
s.substring(0, fStartOffset ) +
s.substring(fEndOffset)
);
// Nothing is partially selected, so collapse to start point
collapse( true );
}
if ( how==DELETE_CONTENTS)
return null;
frag.appendChild( fDocument.createTextNode(sub) );
return frag;
}
// Copy nodes between the start/end offsets.
Node n = getSelectedNode( fStartContainer, fStartOffset );
int cnt = fEndOffset - fStartOffset;
while( cnt > 0 )
{
Node sibling = n.getNextSibling();
Node xferNode = traverseFullySelected( n, how );
if ( frag!=null )
frag.appendChild( xferNode );
--cnt;
n = sibling;
}
// Nothing is partially selected, so collapse to start point
if ( how != CLONE_CONTENTS )
collapse( true );
return frag;
}
/**
* Visits the nodes selected by this range when we know
* a-priori that the start and end containers are not the
* same, but the start container is an ancestor of the
* end container. This method is invoked by the generic
* traverse method.
*
* @param endAncestor
* The ancestor of the end container that is a direct child
* of the start container.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a document fragment containing the range's content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but sill
* produced cloned content in a document fragment
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes.
*
*
* @return Returns a document fragment containing any
* copied or extracted nodes. If the how
* parameter was DELETE_CONTENTS, the
* return value is null.
*/
private DocumentFragment
traverseCommonStartContainer( Node endAncestor, int how )
{
DocumentFragment frag = null;
if ( how!=DELETE_CONTENTS)
frag = fDocument.createDocumentFragment();
Node n = traverseRightBoundary( endAncestor, how );
if ( frag!=null )
frag.appendChild( n );
int endIdx = indexOf( endAncestor, fStartContainer );
int cnt = endIdx - fStartOffset;
if ( cnt <=0 )
{
// Collapse to just before the endAncestor, which
// is partially selected.
if ( how != CLONE_CONTENTS )
{
setEndBefore( endAncestor );
collapse( false );
}
return frag;
}
n = endAncestor.getPreviousSibling();
while( cnt > 0 )
{
Node sibling = n.getPreviousSibling();
Node xferNode = traverseFullySelected( n, how );
if ( frag!=null )
frag.insertBefore( xferNode, frag.getFirstChild() );
--cnt;
n = sibling;
}
// Collapse to just before the endAncestor, which
// is partially selected.
if ( how != CLONE_CONTENTS )
{
setEndBefore( endAncestor );
collapse( false );
}
return frag;
}
/**
* Visits the nodes selected by this range when we know
* a-priori that the start and end containers are not the
* same, but the end container is an ancestor of the
* start container. This method is invoked by the generic
* traverse method.
*
* @param startAncestor
* The ancestor of the start container that is a direct
* child of the end container.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a document fragment containing the range's content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but sill
* produced cloned content in a document fragment
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes.
*
*
* @return Returns a document fragment containing any
* copied or extracted nodes. If the how
* parameter was DELETE_CONTENTS, the
* return value is null.
*/
private DocumentFragment
traverseCommonEndContainer( Node startAncestor, int how )
{
DocumentFragment frag = null;
if ( how!=DELETE_CONTENTS)
frag = fDocument.createDocumentFragment();
Node n = traverseLeftBoundary( startAncestor, how );
if ( frag!=null )
frag.appendChild( n );
int startIdx = indexOf( startAncestor, fEndContainer );
++startIdx; // Because we already traversed it....
int cnt = fEndOffset - startIdx;
n = startAncestor.getNextSibling();
while( cnt > 0 )
{
Node sibling = n.getNextSibling();
Node xferNode = traverseFullySelected( n, how );
if ( frag!=null )
frag.appendChild( xferNode );
--cnt;
n = sibling;
}
if ( how != CLONE_CONTENTS )
{
setStartAfter( startAncestor );
collapse( true );
}
return frag;
}
/**
* Visits the nodes selected by this range when we know
* a-priori that the start and end containers are not
* the same, and we also know that neither the start
* nor end container is an ancestor of the other.
* This method is invoked by
* the generic traverse method.
*
* @param startAncestor
* Given a common ancestor of the start and end containers,
* this parameter is the ancestor (or self) of the start
* container that is a direct child of the common ancestor.
*
* @param endAncestor
* Given a common ancestor of the start and end containers,
* this parameter is the ancestor (or self) of the end
* container that is a direct child of the common ancestor.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a document fragment containing the range's content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but sill
* produced cloned content in a document fragment
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes.
*
*
* @return Returns a document fragment containing any
* copied or extracted nodes. If the how
* parameter was DELETE_CONTENTS, the
* return value is null.
*/
private DocumentFragment
traverseCommonAncestors( Node startAncestor, Node endAncestor, int how )
{
DocumentFragment frag = null;
if ( how!=DELETE_CONTENTS)
frag = fDocument.createDocumentFragment();
Node n = traverseLeftBoundary( startAncestor, how );
if ( frag!=null )
frag.appendChild( n );
Node commonParent = startAncestor.getParentNode();
int startOffset = indexOf( startAncestor, commonParent );
int endOffset = indexOf( endAncestor, commonParent );
++startOffset;
int cnt = endOffset - startOffset;
Node sibling = startAncestor.getNextSibling();
while( cnt > 0 )
{
Node nextSibling = sibling.getNextSibling();
n = traverseFullySelected( sibling, how );
if ( frag!=null )
frag.appendChild( n );
sibling = nextSibling;
--cnt;
}
n = traverseRightBoundary( endAncestor, how );
if ( frag!=null )
frag.appendChild( n );
if ( how != CLONE_CONTENTS )
{
setStartAfter( startAncestor );
collapse( true );
}
return frag;
}
/**
* Traverses the "right boundary" of this range and
* operates on each "boundary node" according to the
* how parameter. It is a-priori assumed
* by this method that the right boundary does
* not contain the range's start container.
*
* A "right boundary" is best visualized by thinking
* of a sample tree:
* A
* /|\
* / | \
* / | \
* B C D
* /|\ /|\
* E F G H I J
*
* Imagine first a range that begins between the
* "E" and "F" nodes and ends between the
* "I" and "J" nodes. The start container is
* "B" and the end container is "D". Given this setup,
* the following applies:
*
* Partially Selected Nodes: B, D
* Fully Selected Nodes: F, G, C, H, I
*
* The "right boundary" is the highest subtree node
* that contains the ending container. The root of
* this subtree is always partially selected.
*
* In this example, the nodes that are traversed
* as "right boundary" nodes are: H, I, and D.
*
* @param root The node that is the root of the "right boundary" subtree.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a node containing the boundaries content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* produced cloned content.
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes within the boundary.
*
*
* @return Returns a node that is the result of visiting nodes.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traverseRightBoundary( Node root, int how )
{
Node next = getSelectedNode( fEndContainer, fEndOffset-1 );
boolean isFullySelected = ( next!=fEndContainer );
if ( next==root )
return traverseNode( next, isFullySelected, false, how );
Node parent = next.getParentNode();
Node clonedParent = traverseNode( parent, false, false, how );
while( parent!=null )
{
while( next!=null )
{
Node prevSibling = next.getPreviousSibling();
Node clonedChild =
traverseNode( next, isFullySelected, false, how );
if ( how!=DELETE_CONTENTS )
{
clonedParent.insertBefore(
clonedChild,
clonedParent.getFirstChild()
);
}
isFullySelected = true;
next = prevSibling;
}
if ( parent==root )
return clonedParent;
next = parent.getPreviousSibling();
parent = parent.getParentNode();
Node clonedGrandParent = traverseNode( parent, false, false, how );
if ( how!=DELETE_CONTENTS )
clonedGrandParent.appendChild( clonedParent );
clonedParent = clonedGrandParent;
}
// should never occur
return null;
}
/**
* Traverses the "left boundary" of this range and
* operates on each "boundary node" according to the
* how parameter. It is a-priori assumed
* by this method that the left boundary does
* not contain the range's end container.
*
* A "left boundary" is best visualized by thinking
* of a sample tree:
*
* A
* /|\
* / | \
* / | \
* B C D
* /|\ /|\
* E F G H I J
*
* Imagine first a range that begins between the
* "E" and "F" nodes and ends between the
* "I" and "J" nodes. The start container is
* "B" and the end container is "D". Given this setup,
* the following applies:
*
* Partially Selected Nodes: B, D
* Fully Selected Nodes: F, G, C, H, I
*
* The "left boundary" is the highest subtree node
* that contains the starting container. The root of
* this subtree is always partially selected.
*
* In this example, the nodes that are traversed
* as "left boundary" nodes are: F, G, and B.
*
* @param root The node that is the root of the "left boundary" subtree.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will produce
* a node containing the boundaries content.
* Partially selected nodes are copied, but fully
* selected nodes are moved.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* produced cloned content.
*
* DELETE_CONTENTS - will delete from
* the context tree of the range, all fully selected
* nodes within the boundary.
*
*
* @return Returns a node that is the result of visiting nodes.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traverseLeftBoundary( Node root, int how )
{
Node next = getSelectedNode( getStartContainer(), getStartOffset() );
boolean isFullySelected = ( next!=getStartContainer() );
if ( next==root )
return traverseNode( next, isFullySelected, true, how );
Node parent = next.getParentNode();
Node clonedParent = traverseNode( parent, false, true, how );
while( parent!=null )
{
while( next!=null )
{
Node nextSibling = next.getNextSibling();
Node clonedChild =
traverseNode( next, isFullySelected, true, how );
if ( how!=DELETE_CONTENTS )
clonedParent.appendChild(clonedChild);
isFullySelected = true;
next = nextSibling;
}
if ( parent==root )
return clonedParent;
next = parent.getNextSibling();
parent = parent.getParentNode();
Node clonedGrandParent = traverseNode( parent, false, true, how );
if ( how!=DELETE_CONTENTS )
clonedGrandParent.appendChild( clonedParent );
clonedParent = clonedGrandParent;
}
// should never occur
return null;
}
/**
* Utility method for traversing a single node.
* Does not properly handle a text node containing both the
* start and end offsets. Such nodes should
* have been previously detected and been routed to traverseTextNode.
*
* @param n The node to be traversed.
*
* @param isFullySelected
* Set to true if the node is fully selected. Should be
* false otherwise.
* Note that although the DOM 2 specification says that a
* text node that is boththe start and end container is not
* selected, we treat it here as if it were partially
* selected.
*
* @param isLeft Is true if we are traversing the node as part of navigating
* the "left boundary" of the range. If this value is false,
* it implies we are navigating the "right boundary" of the
* range.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will simply
* return the original node.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* return a cloned node.
*
* DELETE_CONTENTS - will delete the
* node from it's parent, but will return null.
*
*
* @return Returns a node that is the result of visiting the node.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traverseNode( Node n, boolean isFullySelected, boolean isLeft, int how )
{
if ( isFullySelected )
return traverseFullySelected( n, how );
if ( n.getNodeType()==Node.TEXT_NODE )
return traverseTextNode( n, isLeft, how );
return traversePartiallySelected( n, how );
}
/**
* Utility method for traversing a single node when
* we know a-priori that the node if fully
* selected.
*
* @param n The node to be traversed.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will simply
* return the original node.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* return a cloned node.
*
* DELETE_CONTENTS - will delete the
* node from it's parent, but will return null.
*
*
* @return Returns a node that is the result of visiting the node.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traverseFullySelected( Node n, int how )
{
switch( how )
{
case CLONE_CONTENTS:
return n.cloneNode( true );
case EXTRACT_CONTENTS:
if ( n.getNodeType()==Node.DOCUMENT_TYPE_NODE )
{
// TBD: This should be a HIERARCHY_REQUEST_ERR
throw new RangeExceptionImpl(
RangeException.INVALID_NODE_TYPE_ERR,
"DOM012 Invalid node type");
}
return n;
case DELETE_CONTENTS:
n.getParentNode().removeChild(n);
return null;
}
return null;
}
/**
* Utility method for traversing a single node when
* we know a-priori that the node if partially
* selected and is not a text node.
*
* @param n The node to be traversed.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will simply
* return the original node.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* return a cloned node.
*
* DELETE_CONTENTS - will delete the
* node from it's parent, but will return null.
*
*
* @return Returns a node that is the result of visiting the node.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traversePartiallySelected( Node n, int how )
{
switch( how )
{
case DELETE_CONTENTS:
return null;
case CLONE_CONTENTS:
case EXTRACT_CONTENTS:
return n.cloneNode( false );
}
return null;
}
/**
* Utility method for traversing a text node that we know
* a-priori to be on a left or right boundary of the range.
* This method does not properly handle text nodes that contain
* both the start and end points of the range.
*
* @param n The node to be traversed.
*
* @param isLeft Is true if we are traversing the node as part of navigating
* the "left boundary" of the range. If this value is false,
* it implies we are navigating the "right boundary" of the
* range.
*
* @param how Specifies what type of traversal is being
* requested (extract, clone, or delete).
* Legal values for this argument are:
*
*
* EXTRACT_CONTENTS - will simply
* return the original node.
*
* CLONE_CONTENTS - will leave the
* context tree of the range undisturbed, but will
* return a cloned node.
*
* DELETE_CONTENTS - will delete the
* node from it's parent, but will return null.
*
*
* @return Returns a node that is the result of visiting the node.
* If the traversal operation is
* DELETE_CONTENTS the return value is null.
*/
private Node traverseTextNode( Node n, boolean isLeft, int how )
{
String txtValue = n.getNodeValue();
String newNodeValue;
String oldNodeValue;
if ( isLeft )
{
int offset = getStartOffset();
newNodeValue = txtValue.substring( offset );
oldNodeValue = txtValue.substring( 0, offset );
}
else
{
int offset = getEndOffset();
newNodeValue = txtValue.substring( 0, offset );
oldNodeValue = txtValue.substring( offset );
}
if ( how != CLONE_CONTENTS )
n.setNodeValue( oldNodeValue );
if ( how==DELETE_CONTENTS )
return null;
Node newNode = n.cloneNode( false );
newNode.setNodeValue( newNodeValue );
return newNode;
}
void checkIndex(Node refNode, int offset) throws DOMException
{
if (offset < 0) {
throw new DOMException(
DOMException.INDEX_SIZE_ERR,
"DOM004 Index out of bounds");
}
int type = refNode.getNodeType();
// If the node contains text, ensure that the
// offset of the range is <= to the length of the text
if (type == Node.TEXT_NODE
|| type == Node.CDATA_SECTION_NODE
|| type == Node.COMMENT_NODE
|| type == Node.PROCESSING_INSTRUCTION_NODE) {
if (offset > refNode.getNodeValue().length()) {
throw new DOMException(DOMException.INDEX_SIZE_ERR,
"DOM004 Index out of bounds");
}
}
else {
// Since the node is not text, ensure that the offset
// is valid with respect to the number of child nodes
if (offset > refNode.getChildNodes().getLength()) {
throw new DOMException(DOMException.INDEX_SIZE_ERR,
"DOM004 Index out of bounds");
}
}
}
/**
* Given a node, calculate what the Range's root container
* for that node would be.
*/
private Node getRootContainer( Node node )
{
if ( node==null )
return null;
while( node.getParentNode()!=null )
node = node.getParentNode();
return node;
}
/**
* Returns true IFF the given node can serve as a container
* for a range's boundary points.
*/
private boolean isLegalContainer( Node node )
{
if ( node==null )
return false;
while( node!=null )
{
switch( node.getNodeType() )
{
case Node.ENTITY_NODE:
case Node.NOTATION_NODE:
case Node.DOCUMENT_TYPE_NODE:
return false;
}
node = node.getParentNode();
}
return true;
}
/**
* Finds the root container for the given node and determines
* if that root container is legal with respect to the
* DOM 2 specification. At present, that means the root
* container must be either an attribute, a document,
* or a document fragment.
*/
private boolean hasLegalRootContainer( Node node )
{
if ( node==null )
return false;
Node rootContainer = getRootContainer( node );
switch( rootContainer.getNodeType() )
{
case Node.ATTRIBUTE_NODE:
case Node.DOCUMENT_NODE:
case Node.DOCUMENT_FRAGMENT_NODE:
return true;
}
return false;
}
/**
* Returns true IFF the given node can be contained by
* a range.
*/
private boolean isLegalContainedNode( Node node )
{
if ( node==null )
return false;
switch( node.getNodeType() )
{
case Node.DOCUMENT_NODE:
case Node.DOCUMENT_FRAGMENT_NODE:
case Node.ATTRIBUTE_NODE:
case Node.ENTITY_NODE:
case Node.NOTATION_NODE:
return false;
}
return true;
}
Node nextNode(Node node, boolean visitChildren) {
if (node == null) return null;
Node result;
if (visitChildren) {
result = node.getFirstChild();
if (result != null) {
return result;
}
}
// if hasSibling, return sibling
result = node.getNextSibling();
if (result != null) {
return result;
}
// return parent's 1st sibling.
Node parent = node.getParentNode();
while (parent != null
&& parent != fDocument
) {
result = parent.getNextSibling();
if (result != null) {
return result;
} else {
parent = parent.getParentNode();
}
} // while (parent != null && parent != fRoot) {
// end of list, return null
return null;
}
/** is a an ancestor of b ? */
boolean isAncestorOf(Node a, Node b) {
for (Node node=b; node != null; node=node.getParentNode()) {
if (node == a) return true;
}
return false;
}
/** what is the index of the child in the parent */
int indexOf(Node child, Node parent) {
if (child.getParentNode() != parent) return -1;
int i = 0;
for(Node node = parent.getFirstChild(); node!= child; node=node.getNextSibling()) {
i++;
}
return i;
}
/**
* Utility method to retrieve a child node by index. This method
* assumes the caller is trying to find out which node is
* selected by the given index. Note that if the index is
* greater than the number of children, this implies that the
* first node selected is the parent node itself.
*
* @param container A container node
*
* @param offset An offset within the container for which a selected node should
* be computed. If the offset is less than zero, or if the offset
* is greater than the number of children, the container is returned.
*
* @return Returns either a child node of the container or the
* container itself.
*/
private Node getSelectedNode( Node container, int offset )
{
if ( container.getNodeType() == Node.TEXT_NODE )
return container;
// This case is an important convenience for
// traverseRightBoundary()
if ( offset<0 )
return container;
Node child = container.getFirstChild();
while( child!=null && offset > 0 )
{
--offset;
child = child.getNextSibling();
}
if ( child!=null )
return child;
return container;
}
}