DOMDataBinding.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */
package org.apache.tuscany.sca.databinding.xml;


import javax.xml.namespace.QName;

import org.apache.tuscany.sca.common.xml.dom.DOMHelper;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.databinding.BaseDataBinding;
import org.apache.tuscany.sca.databinding.TransformationContext;
import org.apache.tuscany.sca.databinding.WrapperHandler;
import org.apache.tuscany.sca.interfacedef.DataType;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.interfacedef.util.XMLType;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;

/**
 * DOM DataBinding
 *
 * @version $Rev$ $Date$
 * @tuscany.spi.extension.asclient
 */
public class DOMDataBinding extends BaseDataBinding {
    public static final String NAME = Node.class.getName();

    public static final String ROOT_NAMESPACE = "http://tuscany.apache.org/xmlns/sca/databinding/dom/1.0";
    public static final QName ROOT_ELEMENT = new QName(ROOT_NAMESPACE, "root");
    
    private DOMHelper domHelper;

    public DOMDataBinding(ExtensionPointRegistry registry) {
        super(NAME, Node.class);
        this.domHelper = DOMHelper.getInstance(registry);
    }

    @Override
    public WrapperHandler getWrapperHandler() {
        return new DOMWrapperHandler(domHelper);
    }

    @Override
    public Object copy(Object source,
                       DataType dataType,
                       DataType targetDataType,
                       Operation operation,
                       Operation targetOperation) {
        if (Node.class.isAssignableFrom(source.getClass())) {
            Node nodeSource = (Node)source;
            return nodeSource.cloneNode(true);
        }
        return super.copy(source, dataType, targetDataType, operation, targetOperation);
    }

    @Override
    public boolean introspect(DataType type, Operation operation) {
        if (Node.class.isAssignableFrom(type.getPhysical())) {
            if (type.getLogical() == null) {
                type.setLogical(new XMLType(ROOT_ELEMENT, null));
            }
            type.setDataBinding(NAME);
            return true;
        }
        return false;
    }

    /**
     * @param context
     * @param element
     */
    public static Element adjustElementName(TransformationContext context, Element element) {
        if (context != null) {
            DataType dataType = context.getTargetDataType();
            Object logical = dataType == null ? null : dataType.getLogical();
            if (!(logical instanceof XMLType)) {
                return element;
            }
            XMLType xmlType = (XMLType)logical;
            QName name = new QName(element.getNamespaceURI(), element.getLocalName());
            if (xmlType.isElement() && !xmlType.getElementName().equals(name)) {
                QName newName = xmlType.getElementName();
                String prefix = newName.getPrefix();
                String qname = newName.getLocalPart();
                if (prefix != null && !prefix.equals("")) {
                    qname = prefix + ":" + qname;
                }
                Document doc = element.getOwnerDocument();
                Element newElement = doc.createElementNS(newName.getNamespaceURI(), qname);
                // Copy the attributes to the new element
                NamedNodeMap attrs = element.getAttributes();
                for (int i = 0; i < attrs.getLength(); i++) {
                    Attr attr = (Attr)doc.importNode(attrs.item(i), true);
                    newElement.getAttributes().setNamedItem(attr);
                }
    
                // Move all the children
                while (element.hasChildNodes()) {
                    newElement.appendChild(element.getFirstChild());
                }
    
                // Replace the old node with the new node
                if (element.getParentNode() != null) {
                    element.getParentNode().replaceChild(newElement, element);
                }
    
                return newElement;
            }
        }
        return element;
    }
}