parentnode.java

来自「JAVA 所有包」· Java 代码 · 共 1,032 行 · 第 1/3 页

            // otherwise request a cache object
            fNodeListCache = ownerDocument.getNodeListCache(this);
        }
        if (fNodeListCache.fLength == -1) { // is the cached length invalid ?
            int l;
            ChildNode n;
            // start from the cached node if we have one
            if (fNodeListCache.fChildIndex != -1 &&
                fNodeListCache.fChild != null) {
                l = fNodeListCache.fChildIndex;
                n = fNodeListCache.fChild;
            } else {
                n = firstChild;
                l = 0;
            }
            while (n != null) {
                l++;
                n = n.nextSibling;
            }
            fNodeListCache.fLength = l;
        }

        return fNodeListCache.fLength;

    } // nodeListGetLength():int

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

    /**
     * Return the Nth immediate child of this node, or null if the index is
     * out of bounds.  Use to implement NodeList.item().
     * @param index int
     */
    private Node nodeListItem(int index) {

        if (fNodeListCache == null) {
            // get rid of trivial case
            if (firstChild == lastChild()) {
                return index == 0 ? firstChild : null;
            }
            // otherwise request a cache object
            fNodeListCache = ownerDocument.getNodeListCache(this);
        }
        int i = fNodeListCache.fChildIndex;
        ChildNode n = fNodeListCache.fChild;
        boolean firstAccess = true;
        // short way
        if (i != -1 && n != null) {
            firstAccess = false;
            if (i < index) {
                while (i < index && n != null) {
                    i++;
                    n = n.nextSibling;
                }
            }
            else if (i > index) {
                while (i > index && n != null) {
                    i--;
                    n = n.previousSibling();
                }
            }
        }
        else {
            // long way
            if (index < 0) {
                return null;
            }
            n = firstChild;
            for (i = 0; i < index && n != null; i++) {
                n = n.nextSibling;
            }
        }

        // release cache if reaching last child or first child
        if (!firstAccess && (n == firstChild || n == lastChild())) {
            fNodeListCache.fChildIndex = -1;
            fNodeListCache.fChild = null;
            ownerDocument.freeNodeListCache(fNodeListCache);
            // we can keep using the cache until it is actually reused
            // fNodeListCache will be nulled by the pool (document) if that
            // happens.
            // fNodeListCache = null;
        }
        else {
            // otherwise update it
            fNodeListCache.fChildIndex = i;
            fNodeListCache.fChild = n;
        }
        return n;

    } // nodeListItem(int):Node

    /**
     * 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) {
        return nodeListItem(index);
    } // item(int):Node

    /**
     * Create a NodeList to access children that is use by subclass elements
     * that have methods named getLength() or item(int).  ChildAndParentNode
     * optimizes getChildNodes() by implementing NodeList itself.  However if
     * a subclass Element implements methods with the same name as the NodeList
     * methods, they will override the actually methods in this class.
     * <p>
     * To use this method, the subclass should implement getChildNodes() and
     * have it call this method.  The resulting NodeList instance maybe
     * shared and cached in a transient field, but the cached value must be
     * cleared if the node is cloned.
     */
    protected final NodeList getChildNodesUnoptimized() {
        if (needsSyncChildren()) {
            synchronizeChildren();
        }
        return new NodeList() {
                /**
                 * @see NodeList.getLength()
                 */
                public int getLength() {
                    return nodeListGetLength();
                } // getLength():int
                
                /**
                 * @see NodeList.item(int)
                 */
                public Node item(int index) {
                    return nodeListItem(index);
                } // item(int):Node
            };
    } // getChildNodesUnoptimized():NodeList

    //
    // DOM2: methods, getters, setters
    //

    /**
     * Override default behavior to call normalize() on this Node's
     * children. It is up to implementors or Node to override normalize()
     * to take action.
     */
    public void normalize() {
        // No need to normalize if already normalized.
        if (isNormalized()) {
            return;
        }
        if (needsSyncChildren()) {
            synchronizeChildren();
        }
        ChildNode kid;
        for (kid = firstChild; kid != null; kid = kid.nextSibling) {
            kid.normalize();
        }
        isNormalized(true);
    }

    /**
     * DOM Level 3 WD- Experimental.
     * Override inherited behavior from NodeImpl to support deep equal.
     */
    public boolean isEqualNode(Node arg) {
        if (!super.isEqualNode(arg)) {
            return false;
        }
        // there are many ways to do this test, and there isn't any way
        // better than another. Performance may vary greatly depending on
        // the implementations involved. This one should work fine for us.
        Node child1 = getFirstChild();
        Node child2 = arg.getFirstChild();
        while (child1 != null && child2 != null) {
            if (!((NodeImpl) child1).isEqualNode(child2)) {
                return false;
            }
            child1 = child1.getNextSibling();
            child2 = child2.getNextSibling();
        }
        if (child1 != child2) {
            return false;
        }
        return true;
    }

    //
    // 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();
            }

            // Recursively set kids
            for (ChildNode mykid = firstChild;
                 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(Node)

    //
    // 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)

    /*
     * a class to store some user data along with its handler
     */
    class UserDataRecord implements Serializable {
        /** Serialization version. */
        private static final long serialVersionUID = 3258126977134310455L;
        
        Object fData;
        UserDataHandler fHandler;
        UserDataRecord(Object data, UserDataHandler handler) {
            fData = data;
            fHandler = handler;
        }
    }
} // class ParentNode