attrimpl.java

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        else {
            if (refInternal == null) {
                // this is an append
                ChildNode lastChild = firstChild.previousSibling;
                lastChild.nextSibling = newInternal;
                newInternal.previousSibling = lastChild;
                firstChild.previousSibling = newInternal;
            }
            else {
                // this is an insert
                if (refChild == firstChild) {
                    // at the head of the list
                    firstChild.isFirstChild(false);
                    newInternal.nextSibling = firstChild;
                    newInternal.previousSibling = firstChild.previousSibling;
                    firstChild.previousSibling = newInternal;
                    value = newInternal; // firstChild = newInternal;
                    newInternal.isFirstChild(true);
                }
                else {
                    // somewhere in the middle
                    ChildNode prev = refInternal.previousSibling;
                    newInternal.nextSibling = refInternal;
                    prev.nextSibling = newInternal;
                    refInternal.previousSibling = newInternal;
                    newInternal.previousSibling = prev;
                }
            }
        }

        changed();

        // notify document
        ownerDocument.insertedNode(this, newInternal, replace);

        checkNormalizationAfterInsert(newInternal);

        return newChild;

    } // internalInsertBefore(Node,Node,int):Node

    /**
     * Remove a child from this Node. The removed child's subtree
     * remains intact so it may be re-inserted elsewhere.
     *
     * @return oldChild, in its new state (removed).
     *
     * @throws DOMException(NOT_FOUND_ERR) if oldChild is not a child of
     * this node.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node removeChild(Node oldChild) 
        throws DOMException {
        // Tail-call, should be optimizable
        if (hasStringValue()) {
            // we don't have any child per say so it can't be one of them!
            String msg = DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "NOT_FOUND_ERR", null);
            throw new DOMException(DOMException.NOT_FOUND_ERR, msg);            
        }
        return internalRemoveChild(oldChild, false);
    } // removeChild(Node) :Node
     
    /** NON-DOM INTERNAL: Within DOM actions,we sometimes need to be able
     * to control which mutation events are spawned. This version of the
     * removeChild operation allows us to do so. It is not intended
     * for use by application programs.
     */
    Node internalRemoveChild(Node oldChild, boolean replace)
        throws DOMException {

        CoreDocumentImpl ownerDocument = ownerDocument();
        if (ownerDocument.errorChecking) {
            if (isReadOnly()) {
                String msg = DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "NO_MODIFICATION_ALLOWED_ERR", null);
                throw new DOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR, msg);
            }
            if (oldChild != null && oldChild.getParentNode() != this) {
                String msg = DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "NOT_FOUND_ERR", null);
                throw new DOMException(DOMException.NOT_FOUND_ERR, msg);
            }
        }

        ChildNode oldInternal = (ChildNode) oldChild;

        // notify document
        ownerDocument.removingNode(this, oldInternal, replace);

        // Patch linked list around oldChild
        // Note: lastChild == firstChild.previousSibling
        if (oldInternal == value) { // oldInternal == firstChild
            // removing first child
            oldInternal.isFirstChild(false);
            // next line is: firstChild = oldInternal.nextSibling
            value = oldInternal.nextSibling;
            ChildNode firstChild = (ChildNode) value;
            if (firstChild != null) {
                firstChild.isFirstChild(true);
                firstChild.previousSibling = oldInternal.previousSibling;
            }
        } else {
            ChildNode prev = oldInternal.previousSibling;
            ChildNode next = oldInternal.nextSibling;
            prev.nextSibling = next;
            if (next == null) {
                // removing last child
                ChildNode firstChild = (ChildNode) value;
                firstChild.previousSibling = prev;
            } else {
                // removing some other child in the middle
                next.previousSibling = prev;
            }
        }

        // Save previous sibling for normalization checking.
        ChildNode oldPreviousSibling = oldInternal.previousSibling();

        // Remove oldInternal's references to tree
        oldInternal.ownerNode       = ownerDocument;
        oldInternal.isOwned(false);
        oldInternal.nextSibling     = null;
        oldInternal.previousSibling = null;

        changed();

        // notify document
        ownerDocument.removedNode(this, replace);

        checkNormalizationAfterRemove(oldPreviousSibling);

        return oldInternal;

    } // internalRemoveChild(Node,int):Node

    /**
     * Make newChild occupy the location that oldChild used to
     * have. Note that newChild will first be removed from its previous
     * parent, if any. Equivalent to inserting newChild before oldChild,
     * then removing oldChild.
     *
     * @return oldChild, in its new state (removed).
     *
     * @throws DOMException(HIERARCHY_REQUEST_ERR) if newChild is of a
     * type that shouldn't be a child of this node, or if newChild is
     * one of our ancestors.
     *
     * @throws DOMException(WRONG_DOCUMENT_ERR) if newChild has a
     * different owner document than we do.
     *
     * @throws DOMException(NOT_FOUND_ERR) if oldChild is not a child of
     * this node.
     *
     * @throws DOMException(NO_MODIFICATION_ALLOWED_ERR) if this node is
     * read-only.
     */
    public Node replaceChild(Node newChild, Node oldChild)
        throws DOMException {

        makeChildNode();

        // If Mutation Events are being generated, this operation might
        // throw aggregate events twice when modifying an Attr -- once 
        // on insertion and once on removal. DOM Level 2 does not specify 
        // this as either desirable or undesirable, but hints that
        // aggregations should be issued only once per user request.

        // notify document
        CoreDocumentImpl ownerDocument = ownerDocument();
        ownerDocument.replacingNode(this);

        internalInsertBefore(newChild, oldChild, true);
        if (newChild != oldChild) {
            internalRemoveChild(oldChild, true);
        }

        // notify document
        ownerDocument.replacedNode(this);

        return oldChild;
    }

    //
    // NodeList methods
    //

    /**
     * NodeList method: Count the immediate children of this node
     * @return int
     */
    public int getLength() {

        if (hasStringValue()) {
            return 1;
        }
        ChildNode node = (ChildNode) value;
        int length = 0;
        for (; node != null; node = node.nextSibling) {
            length++;
        }
        return length;

    } // getLength():int

    /**
     * NodeList method: Return the Nth immediate child of this node, or
     * null if the index is out of bounds.
     * @return org.w3c.dom.Node
     * @param Index int
     */
    public Node item(int index) {

        if (hasStringValue()) {
            if (index != 0 || value == null) {
                return null;
            }
            else {
                makeChildNode();
                return (Node) value;
            }
        }
        if (index < 0) {
            return null;
        }
        ChildNode node = (ChildNode) value;
        for (int i = 0; i < index && node != null; i++) {
            node = node.nextSibling;
        } 
        return node;

    } // item(int):Node

    //
    // DOM3
    //

    /**
     * DOM Level 3 WD- Experimental.
     * Override inherited behavior from ParentNode to support deep equal.
     * isEqualNode is always deep on Attr nodes.
     */
    public boolean isEqualNode(Node arg) {
        return super.isEqualNode(arg);
    }

    /**
     * Introduced in DOM Level 3. <p>
     * Checks if a type is derived from another by restriction. See:
     * http://www.w3.org/TR/DOM-Level-3-Core/core.html#TypeInfo-isDerivedFrom
     * 
     * @param ancestorNS 
     *        The namspace of the ancestor type declaration
     * @param ancestorName
     *        The name of the ancestor type declaration
     * @param type
     *        The reference type definition
     * 
     * @return boolean True if the type is derived by restriciton for the
     *         reference type
     */
    public boolean isDerivedFrom(String typeNamespaceArg, 
                                 String typeNameArg, 
                                 int derivationMethod) {
                                 	
        return false;
    }
        

    //
    // Public methods
    //

    /**
     * Override default behavior so that if deep is true, children are also
     * toggled.
     * @see Node
     * <P>
     * Note: this will not change the state of an EntityReference or its
     * children, which are always read-only.
     */
    public void setReadOnly(boolean readOnly, boolean deep) {

        super.setReadOnly(readOnly, deep);

        if (deep) {

            if (needsSyncChildren()) {
                synchronizeChildren();
            }

            if (hasStringValue()) {
                return;
            }
            // Recursively set kids
            for (ChildNode mykid = (ChildNode) value;
                 mykid != null;
                 mykid = mykid.nextSibling) {
                if (mykid.getNodeType() != Node.ENTITY_REFERENCE_NODE) {
                    mykid.setReadOnly(readOnly,true);
                }
            }
        }
    } // setReadOnly(boolean,boolean)

    //
    // Protected methods
    //

    /**
     * Override this method in subclass to hook in efficient
     * internal data structure.
     */
    protected void synchronizeChildren() {
        // By default just change the flag to avoid calling this method again
        needsSyncChildren(false);
    }

    /**
     * Checks the normalized state of this node after inserting a child.
     * If the inserted child causes this node to be unnormalized, then this
     * node is flagged accordingly.
     * The conditions for changing the normalized state are:
     * <ul>
     * <li>The inserted child is a text node and one of its adjacent siblings
     * is also a text node.
     * <li>The inserted child is is itself unnormalized.
     * </ul>
     *
     * @param insertedChild the child node that was inserted into this node
     *
     * @throws NullPointerException if the inserted child is <code>null</code>
     */
    void checkNormalizationAfterInsert(ChildNode insertedChild) {
        // See if insertion caused this node to be unnormalized.
        if (insertedChild.getNodeType() == Node.TEXT_NODE) {
            ChildNode prev = insertedChild.previousSibling();
            ChildNode next = insertedChild.nextSibling;
            // If an adjacent sibling of the new child is a text node,
            // flag this node as unnormalized.
            if ((prev != null && prev.getNodeType() == Node.TEXT_NODE) ||
                (next != null && next.getNodeType() == Node.TEXT_NODE)) {
                isNormalized(false);
            }
        }
        else {
            // If the new child is not normalized,
            // then this node is inherently not normalized.
            if (!insertedChild.isNormalized()) {
                isNormalized(false);
            }
        }
    } // checkNormalizationAfterInsert(ChildNode)

    /**
     * Checks the normalized of this node after removing a child.
     * If the removed child causes this node to be unnormalized, then this
     * node is flagged accordingly.
     * The conditions for changing the normalized state are:
     * <ul>
     * <li>The removed child had two adjacent siblings that were text nodes.
     * </ul>
     *
     * @param previousSibling the previous sibling of the removed child, or
     * <code>null</code>
     */
    void checkNormalizationAfterRemove(ChildNode previousSibling) {
        // See if removal caused this node to be unnormalized.
        // If the adjacent siblings of the removed child were both text nodes,
        // flag this node as unnormalized.
        if (previousSibling != null &&
            previousSibling.getNodeType() == Node.TEXT_NODE) {

            ChildNode next = previousSibling.nextSibling;
            if (next != null && next.getNodeType() == Node.TEXT_NODE) {
                isNormalized(false);
            }
        }
    } // checkNormalizationAfterRemove(ChildNode)

    //
    // Serialization methods
    //

    /** Serialize object. */
    private void writeObject(ObjectOutputStream out) throws IOException {

        // synchronize chilren
        if (needsSyncChildren()) {
            synchronizeChildren();
        }
        // write object
        out.defaultWriteObject();

    } // writeObject(ObjectOutputStream)

    /** Deserialize object. */
    private void readObject(ObjectInputStream ois)
        throws ClassNotFoundException, IOException {

        // perform default deseralization
        ois.defaultReadObject();

        // hardset synchildren - so we don't try to sync -
        // it does not make any sense to try to synchildren when we just
        // deserialize object.
        needsSyncChildren(false);

    } // readObject(ObjectInputStream)


} // class AttrImpl