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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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

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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;

    }

}