elementimpl.java

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/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed 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 com.sun.org.apache.xerces.internal.dom;

import org.w3c.dom.Attr;
import org.w3c.dom.DOMException;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

import org.w3c.dom.TypeInfo;
import com.sun.org.apache.xerces.internal.util.URI;

/**
 * Elements represent most of the "markup" and structure of the
 * document.  They contain both the data for the element itself
 * (element name and attributes), and any contained nodes, including
 * document text (as children).
 * <P>
 * Elements may have Attributes associated with them; the API for this is
 * defined in Node, but the function is implemented here. In general, XML
 * applications should retrive Attributes as Nodes, since they may contain
 * entity references and hence be a fairly complex sub-tree. HTML users will
 * be dealing with simple string values, and convenience methods are provided
 * to work in terms of Strings.
 * <P>
 * ElementImpl does not support Namespaces. ElementNSImpl, which inherits from
 * it, does.
 * @see ElementNSImpl
 * 
 * @xerces.internal
 *
 * @author Arnaud  Le Hors, IBM
 * @author Joe Kesselman, IBM
 * @author Andy Clark, IBM
 * @author Ralf Pfeiffer, IBM
 * @version $Id: ElementImpl.java,v 1.3 2005/09/02 05:52:22 neerajbj Exp $
 * @since  PR-DOM-Level-1-19980818.
 */
public class ElementImpl
    extends ParentNode
    implements Element, TypeInfo {

    //
    // Constants
    //

    /** Serialization version. */
    static final long serialVersionUID = 3717253516652722278L;
    //
    // Data
    //

    /** Element name. */
    protected String name;

    /** Attributes. */
    protected AttributeMap attributes;

    //
    // Constructors
    //

    /** Factory constructor. */
    public ElementImpl(CoreDocumentImpl ownerDoc, String name) {
    	super(ownerDoc);
        this.name = name;
        needsSyncData(true);    // synchronizeData will initialize attributes
    }

    // for ElementNSImpl
    protected ElementImpl() {}

    // Support for DOM Level 3 renameNode method.
    // Note: This only deals with part of the pb. CoreDocumentImpl
    // does all the work.
    void rename(String name) {
        if (needsSyncData()) {
            synchronizeData();
        }
	    this.name = name;
        reconcileDefaultAttributes();
    }

    //
    // Node methods
    //


    /**
     * A short integer indicating what type of node this is. The named
     * constants for this value are defined in the org.w3c.dom.Node interface.
     */
    public short getNodeType() {
        return Node.ELEMENT_NODE;
    }

    /**
     * Returns the element name
     */
    public String getNodeName() {
        if (needsSyncData()) {
            synchronizeData();
        }
        return name;
    }

    /**
     * Retrieve all the Attributes as a set. Note that this API is inherited
     * from Node rather than specified on Element; in fact only Elements will
     * ever have Attributes, but they want to allow folks to "blindly" operate
     * on the tree as a set of Nodes.
     */
    public NamedNodeMap getAttributes() {

        if (needsSyncData()) {
            synchronizeData();
        }
        if (attributes == null) {
            attributes = new AttributeMap(this, null);
        }
        return attributes;

    } // getAttributes():NamedNodeMap

    /**
     * Return a duplicate copy of this Element. Note that its children
     * will not be copied unless the "deep" flag is true, but Attributes
     * are <i>always</i> replicated.
     *
     * @see org.w3c.dom.Node#cloneNode(boolean)
     */
    public Node cloneNode(boolean deep) {

    	ElementImpl newnode = (ElementImpl) super.cloneNode(deep);
    	// Replicate NamedNodeMap rather than sharing it.
        if (attributes != null) {
            newnode.attributes = (AttributeMap) attributes.cloneMap(newnode);
        }
    	return newnode;

    } // cloneNode(boolean):Node

   /**
     * DOM Level 3 WD - Experimental.
     * Retrieve baseURI
     */
    public String getBaseURI() {

        if (needsSyncData()) {
            synchronizeData();
        }
        // Absolute base URI is computed according to 
        // XML Base (http://www.w3.org/TR/xmlbase/#granularity)
        // 1. The base URI specified by an xml:base attribute on the element, 
        // if one exists
        if (attributes != null) {
            Attr attrNode = (Attr)attributes.getNamedItem("xml:base");
            if (attrNode != null) {
                String uri =  attrNode.getNodeValue();
                if (uri.length() != 0 ) {// attribute value is always empty string
                    try {
                       uri = new URI(uri).toString();
                    }
                    catch (com.sun.org.apache.xerces.internal.util.URI.MalformedURIException e) {
                        // This may be a relative URI.
                        
                        // Make any parentURI into a URI object to use with the URI(URI, String) constructor
                        String parentBaseURI = (this.ownerNode != null) ? this.ownerNode.getBaseURI() : null;
                        if (parentBaseURI != null){
                            try{
                                uri = new URI(new URI(parentBaseURI), uri).toString();
                            }
                            catch (com.sun.org.apache.xerces.internal.util.URI.MalformedURIException ex){
                                // This should never happen: parent should have checked the URI and returned null if invalid.
                                return null;
                            }
                            return uri;
                        }
                        return null;
                    }
                    return uri;
                }
            }
        }

        // 2.the base URI of the element's parent element within the 
        // document or external entity, if one exists 
		// 3. the base URI of the document entity or external entity 
		// containing the element
		
		// ownerNode serves as a parent or as document
		String baseURI = (this.ownerNode != null) ? this.ownerNode.getBaseURI() : null ;
        //base URI of parent element is not null
        if(baseURI != null){
            try {
                //return valid absolute base URI
               return new URI(baseURI).toString();
            }
            catch (com.sun.org.apache.xerces.internal.util.URI.MalformedURIException e){
                return null;
            }
        }
        return null;
    } //getBaseURI



    /**
     * NON-DOM
     * set the ownerDocument of this node, its children, and its attributes
     */
    void setOwnerDocument(CoreDocumentImpl doc) {
	super.setOwnerDocument(doc);
        if (attributes != null) {
            attributes.setOwnerDocument(doc);
        }
    }

    //
    // Element methods
    //

    /**
     * Look up a single Attribute by name. Returns the Attribute's
     * string value, or an empty string (NOT null!) to indicate that the
     * name did not map to a currently defined attribute.
     * <p>
     * Note: Attributes may contain complex node trees. This method
     * returns the "flattened" string obtained from Attribute.getValue().
     * If you need the structure information, see getAttributeNode().
     */
    public String getAttribute(String name) {

        if (needsSyncData()) {
            synchronizeData();
        }
        if (attributes == null) {
            return "";
        }
        Attr attr = (Attr)(attributes.getNamedItem(name));
        return (attr == null) ? "" : attr.getValue();

    } // getAttribute(String):String


    /**
     * Look up a single Attribute by name. Returns the Attribute Node,
     * so its complete child tree is available. This could be important in
     * XML, where the string rendering may not be sufficient information.
     * <p>
     * If no matching attribute is available, returns null.
     */
    public Attr getAttributeNode(String name) {

        if (needsSyncData()) {
            synchronizeData();
        }
        if (attributes == null) {
            return null;
        }
        return (Attr)attributes.getNamedItem(name);

    } // getAttributeNode(String):Attr


    /**
     * Returns a NodeList of all descendent nodes (children,
     * grandchildren, and so on) which are Elements and which have the
     * specified tag name.
     * <p>
     * Note: NodeList is a "live" view of the DOM. Its contents will
     * change as the DOM changes, and alterations made to the NodeList
     * will be reflected in the DOM.
     *
     * @param tagname The type of element to gather. To obtain a list of
     * all elements no matter what their names, use the wild-card tag
     * name "*".
     *
     * @see DeepNodeListImpl
     */
    public NodeList getElementsByTagName(String tagname) {
    	return new DeepNodeListImpl(this,tagname);
    }

    /**
     * Returns the name of the Element. Note that Element.nodeName() is
     * defined to also return the tag name.
     * <p>
     * This is case-preserving in XML. HTML should uppercasify it on the
     * way in.
     */
    public String getTagName() {
        if (needsSyncData()) {
            synchronizeData();
        }
    	return name;
    }

    /**
     * In "normal form" (as read from a source file), there will never be two
     * Text children in succession. But DOM users may create successive Text
     * nodes in the course of manipulating the document. Normalize walks the
     * sub-tree and merges adjacent Texts, as if the DOM had been written out
     * and read back in again. This simplifies implementation of higher-level
     * functions that may want to assume that the document is in standard form.
     * <p>
     * To normalize a Document, normalize its top-level Element child.
     * <p>
     * As of PR-DOM-Level-1-19980818, CDATA -- despite being a subclass of
     * Text -- is considered "markup" and will _not_ be merged either with
     * normal Text or with other CDATASections.
     */
    public void normalize() {
        // No need to normalize if already normalized.
        if (isNormalized()) {
            return;
        }
        if (needsSyncChildren()) {
            synchronizeChildren();
        }
        ChildNode kid, next;
        for (kid = firstChild; kid != null; kid = next) {
            next = kid.nextSibling;

            // If kid is a text node, we need to check for one of two
            // conditions:
            //   1) There is an adjacent text node
            //   2) There is no adjacent text node, but kid is
            //      an empty text node.
            if ( kid.getNodeType() == Node.TEXT_NODE )
            {
                // If an adjacent text node, merge it with kid
                if ( next!=null && next.getNodeType() == Node.TEXT_NODE )
                {
                    ((Text)kid).appendData(next.getNodeValue());
                    removeChild( next );
                    next = kid; // Don't advance; there might be another.
                }
                else
                {
                    // If kid is empty, remove it
                    if ( kid.getNodeValue() == null || kid.getNodeValue().length() == 0 ) {
                        removeChild( kid );
                    }
                }
            }

            // Otherwise it might be an Element, which is handled recursively
            else if (kid.getNodeType() == Node.ELEMENT_NODE) {
                kid.normalize();
            }
        }

        // We must also normalize all of the attributes
        if ( attributes!=null )
        {
            for( int i=0; i<attributes.getLength(); ++i )
            {
                Node attr = attributes.item(i);
                attr.normalize();
            }
        }

    	// changed() will have occurred when the removeChild() was done,
    	// so does not have to be reissued.

        isNormalized(true);
    } // normalize()

    /**
     * Remove the named attribute from this Element. If the removed