Java example source code file (JAXPPrefixResolver.java)

This example Java source code file (JAXPPrefixResolver.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

dom, jaxpprefixresolver, namednodemap, namespacecontext, node, s_xmlnamespaceuri, string

The JAXPPrefixResolver.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 1999-2004 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.
 */
// $Id: JAXPPrefixResolver.java,v 1.1.2.1 2005/08/01 01:30:18 jeffsuttor Exp $

package com.sun.org.apache.xpath.internal.jaxp;

import org.w3c.dom.Node;
import org.w3c.dom.NamedNodeMap;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;

import javax.xml.namespace.NamespaceContext;

/**
 * <meta name="usage" content="general"/>
 * This class implements a Default PrefixResolver which
 * can be used to perform prefix-to-namespace lookup
 * for the XPath object.
 * This class delegates the resolution to the passed NamespaceContext
 */
public class JAXPPrefixResolver implements PrefixResolver
{

    private NamespaceContext namespaceContext;


    public JAXPPrefixResolver ( NamespaceContext nsContext ) {
        this.namespaceContext = nsContext;
    }


    public String getNamespaceForPrefix( String prefix ) {
        return namespaceContext.getNamespaceURI( prefix );
    }

    /**
     * Return the base identifier.
     *
     * @return null
     */
    public String getBaseIdentifier() {
        return null;
    }

    /**
     * @see PrefixResolver#handlesNullPrefixes()
     */
    public boolean handlesNullPrefixes() {
        return false;
    }


    /**
     * The URI for the XML namespace.
     * (Duplicate of that found in com.sun.org.apache.xpath.internal.XPathContext).
     */

    public static final String S_XMLNAMESPACEURI =
        "http://www.w3.org/XML/1998/namespace";


    /**
     * Given a prefix and a Context Node, get the corresponding namespace.
     * Warning: This will not work correctly if namespaceContext
     * is an attribute node.
     * @param prefix Prefix to resolve.
     * @param namespaceContext Node from which to start searching for a
     * xmlns attribute that binds a prefix to a namespace.
     * @return Namespace that prefix resolves to, or null if prefix
     * is not bound.
     */
    public String getNamespaceForPrefix(String prefix,
                                      org.w3c.dom.Node namespaceContext) {
        Node parent = namespaceContext;
        String namespace = null;

        if (prefix.equals("xml")) {
            namespace = S_XMLNAMESPACEURI;
        } else {
            int type;

            while ((null != parent) && (null == namespace)
                && (((type = parent.getNodeType()) == Node.ELEMENT_NODE)
                    || (type == Node.ENTITY_REFERENCE_NODE))) {

                if (type == Node.ELEMENT_NODE) {
                    NamedNodeMap nnm = parent.getAttributes();

                    for (int i = 0; i < nnm.getLength(); i++) {
                        Node attr = nnm.item(i);
                        String aname = attr.getNodeName();
                        boolean isPrefix = aname.startsWith("xmlns:");

                        if (isPrefix || aname.equals("xmlns")) {
                            int index = aname.indexOf(':');
                            String p =isPrefix ?aname.substring(index + 1) :"";

                            if (p.equals(prefix)) {
                                namespace = attr.getNodeValue();
                                break;
                            }
                        }
                    }
                }

                parent = parent.getParentNode();
            }
        }
        return namespace;
    }

}