nodeimpl.java

Java的面向对象数据库系统的源代码

     * It does not duplicate it's context, that is, the node's parent or sibling.
     * Initially a clone node has no parents or siblings. However, the node does
     * belong to the same document, since all nodes must belong to some document.
     * The cloned node is never read-only.
     *
     * @param into A node into which to duplicate this one
     * @param deep True if deep cloning is required
     */
    public synchronized void cloneInto( NodeProxy into, boolean deep ) {
        NodeProxy child;

        // falko: this expression cannot be true in ozone so I commented this
        // out
        // Make sure no function messed up with the class types.
//        if (this.getClass() != into.getClass()) {
//            throw new IllegalArgumentException( "Argument 'into' not same type as this node." );
//        }

        // Duplicate node name and value.
        into.setNodeName( _nodeName );
        String nodeValue = getNodeValue();
        if (nodeValue != null) {
            into.setNodeValue( nodeValue );
        }
        into.setOwnerDocument( _ownerDocument );
        if (deep) {
            child = (NodeProxy)getFirstChild();
            while (child != null) {
                into.appendChild( child.cloneNode( true ) );
                child = (NodeProxy)child.getNextSibling();
            }
        }
    }


    public synchronized void setOwnerDocument( Document owner ) {
        Node node;

        if (owner == null) {
            _ownerDocument = null;
        } else {
            if (!(owner instanceof DocumentProxy)) {
                throw new IllegalArgumentException( "Argument 'owner' not of compatible DOM class." );
            }
            _ownerDocument = (DocumentProxy)owner;
        }
        node = getFirstChild();
        while (node != null) {
            ((NodeProxy)node).setOwnerDocument( owner );
            node = node.getNextSibling();
        }
    }


    /**
     * Renders this node read only, preventing it's contents from being modified.
     * Attempts to modify the node's contents will throw an exception. The node's
     * children are also made read-only.
     */
    public synchronized final void setReadOnly() {
        NodeProxy child;

        _readOnly = true;
        // Make all children read-only as well: this allows us to lock a branch
        // but, for example, move it to a different tree.
        child = (NodeProxy)getFirstChild();
        while (child != null) {
            child.setReadOnly();
            child = (NodeProxy)child.getNextSibling();
        }
    }


    /**
     * Returns true if node is read-only and cannot be modified, or if node
     * belongs to a read-only document.
     *
     * @return True if node is read-only and cannot be modified
     * @see #setReadOnly
     */
    public final boolean isReadOnly() {
        return _readOnly;
    }


    /**
     * Returns true if this node supports children. Other methods query this to
     * determine whether to properly support childern, return null or throw an
     * exception in response. The default method returns false.
     *
     * @return True if childern supported by this node type
     */
    boolean supportsChildern() {
        return false;
    }


    /**
     * Returns the <TT>index</TT>-th child of this node. This method is used
     * exclusively by {@link NodeListImpl}.
     *
     * @param index Index of child to retrieve
     * @return The child node or null
     * @see NodeListImpl#item(int)
     */
    public synchronized final Node getChild( int index ) {
        NodeProxy node;

        if (index < 0 || index > _childsCount) {
            return null;
        }
        node = (NodeProxy)getFirstChild();
        while (node != null && index > 0) {
            node = (NodeProxy)node.getNextSibling();
            --index;
        }
        return node;
    }


    /**
     * Returns the number of children in this node.  This method is used
     * exclusively by {@link NodeListImpl}.
     *
     * @return Number of childern in this node
     * @see NodeListImpl#getLength
     */
    public final int getChildCount() {
        return _childsCount;
    }


    /**
     * Hidden constructor creates a new node. Only one constructor is supported,
     * although cloning is also supported. Owner document must be supplied except
     * for {@link DocumentImpl} in which case the document itself becomes its
     * owner. Name must be supplied, either dynamic or static (e.g. "#document#").
     * <P>
     * If <TT>checkName</TT> is true, the supplied named is assumed to be a valid
     * XML name token, one that can contain any Unicode letter and digit, must
     * start with a letter, and may also contain hyphen, underscore, digit or colon.
     *
     * @param owner Document owner of this node, or null
     * @param name Name of node
     * @param value Initial value of node or null
     * @param checkName True if name is an XML name token
     * @throws org.w3c.dom.DOMException <TT>INVALID_CHARACTER_ERR</TT>
     *  Node name cannot contain whitespaces or non-printable characters
     */
    protected NodeImpl( DocumentImpl owner, String name, String value, boolean checkName ) throws DOMException{
        init( owner, name, value, checkName );
    }


    protected NodeImpl() {
    }


    public final void init( DocumentProxy owner, String name, String value, boolean checkName ) throws DOMException {
        char ch;
        int i;

        if (name == null) {
            throw new NullPointerException( "Argument 'name' is null." );
        }

        _nodeName = name;
        _ownerDocument = owner;
        // Check the node name one character at a time to assure that no
        // illegal characters are used. Node name must conform to Name token
        // as defined in XML spec, including use of all Unicode letters and
        // digits.
        if (checkName && name.length() > 0) {
            ch = name.charAt( 0 );
            if (!Character.isLetter( ch ) && ch != '_' && ch != ':') {
                throw new DOMExceptionImpl( DOMException.INVALID_CHARACTER_ERR );
            }
            for (i = 1; i < name.length(); ++i) {
                ch = name.charAt( 1 );
                if (!Character.isLetterOrDigit( ch ) && ch != '_' && ch != ':' && ch != '-' && ch != '.') {
                    throw new DOMExceptionImpl( DOMException.INVALID_CHARACTER_ERR );
                }
            }
        }
        if (value != null) {
            setNodeValue( value );
        }
    }

    /**
     * Element declaration node. Not part of the DOM, identifies an element
     * declaration node appearing in the DTD.
     */
    public final static short ELEMENT_DECL_NODE = 13;


    /**
     * Attributes list declaration node. Not part of the DOM, identifies an
     * attributes list declaration node appearing in the DTD..
     */
    public final static short ATTLIST_DECL_NODE = 14;


    /**
     * Parameter entity declaration node. Not part of the DOM, identifies an
     * internal or external parameter entity declaration node appearing in the
     * DTD (see {@link ParamEntity}).
     */
    public final static short PARAM_ENTITY_NODE = 15;


    /**
     * This node ia part of a double-linked list that belongs to its parent.
     * This reference identifies the next child in the list. Class access
     * required by derived classes.
     */
    NodeProxy _nextNode;

    /**
     * This node ia part of a double-linked list that belongs to its parent.
     * This reference identifies the previous child in the list. Class access
     * required by derived classes.
     */
    NodeProxy _prevNode;

    /**
     * The parent of this node or null if the node has no parent. Class access
     * required by derived classes.
     */
    NodeProxy _parent;

    /**
     * The document owner of this node, or the document itself. If the node belongs
     * to any document, this will point to that document. For a document this will
     * point at the document itself ({@link #getOwnerDocument} will return null,
     * though). Class access required by derived classes.
     */
    DocumentProxy _ownerDocument;

    /**
     * The name of this node. All nodes have names, some are dynamic (e.g. the
     * tag name of an element), others are static (e.g. "#document").
     */
    private String _nodeName;

    /**
     * The value of this node. Not all nodes support values and this might be
     * null for some nodes.
     */
    private String _nodeValue;

    /**
     * The children of this node are arranged in a doubly linked lists.
     * This reference identifies the first child in the list.
     */
    private NodeProxy _firstChild;

    /**
     * The children of this node are arranged in a doubly linked lists.
     * This reference identifies the last child in the list.
     */
    private NodeProxy _lastChild;

    /**
     * Counts how many children nodes belong to this parent. Used to speed up
     * some checks.
     */
    private int _childsCount;

    /**
     * True if this node is read-only and its contents cannot be modified.
     */
    private boolean _readOnly;

    /**
     * Holdes a list of iterators that are observing this node of its
     * childern.
     */
    private NodeIteratorListener[] _iterators;


    /**
     */
    public void writeExternal( ObjectOutput out ) throws IOException {
        out.writeObject( _nextNode );
        out.writeObject( _prevNode );
        out.writeObject( _parent );
        out.writeObject( _ownerDocument );

        //out.writeObject (_nodeName);
        if (_nodeName != null) {
            out.writeByte( 1 );
            out.writeUTF( _nodeName );
        } else {
            out.writeByte( -1 );
        }

        // out.writeObject (_nodeValue);
        if (_nodeValue != null) {
            out.writeByte( 1 );
            out.writeUTF( _nodeValue );
        } else {
            out.writeByte( -1 );
        }

        out.writeObject( _firstChild );
        out.writeObject( _lastChild );
        out.writeInt( _childsCount );
        out.writeBoolean( _readOnly );

        if (_iterators != null) {
            int len = _iterators.length;
            out.writeInt( len );
            for (int i = 0; i < len; i++) {
                out.writeObject( _iterators[i] );
            }
        } else {
            out.writeInt( -1 );
        }
    }


    /**
     */
    public void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
        _nextNode = (NodeProxy)in.readObject();
        _prevNode = (NodeProxy)in.readObject();
        _parent = (NodeProxy)in.readObject();
        _ownerDocument = (DocumentProxy)in.readObject();

        int n = in.readByte();
        if (n > 0) {
            _nodeName = in.readUTF();
        } else {
            _nodeName = null;
        }

        //_nodeValue = (String)in.readObject();
        n = in.readByte();
        if (n > 0) {
            _nodeValue = in.readUTF();
        } else {
            _nodeValue = null;
        }

        _firstChild = (NodeProxy)in.readObject();
        _lastChild = (NodeProxy)in.readObject();
        _childsCount = in.readInt();
        _readOnly = in.readBoolean();

        int len = in.readInt();
        if (len > -1) {
            _iterators = new NodeIteratorListener[len];
            for (int i = 0; i < len; i++) {
                _iterators[i] = (NodeIteratorListener)in.readObject();
            }
        } else {
            _iterators = null;
        }
    }

    public boolean isSupported(String s, String s1) {
        throw new DOMExceptionImpl( DOMException.NOT_SUPPORTED_ERR,
                "Node.getLocalName(): ozone's persistent DOM doesn't support DOM level 2 yet." );
    }
}