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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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package com.sun.tools.internal.xjc.reader.internalizer;

import java.util.Iterator;

import javax.xml.XMLConstants;

import javax.xml.namespace.NamespaceContext;

import org.w3c.dom.Element;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.Node;

/**

 * Implements {@link NamespaceContext} by looking at the in-scope

 * namespace binding of a DOM element.

 *

 * @author Kohsuke Kawaguchi

 */

final class NamespaceContextImpl implements NamespaceContext {

    private final Element e;

    public NamespaceContextImpl(Element e) {

        this.e = e;

    }

    public String getNamespaceURI(String prefix) {

        Node parent = e;

        String namespace = null;

        final String prefixColon = prefix + ':';

        if (prefix.equals("xml")) {

            namespace = XMLConstants.XML_NS_URI;

        } else {

            int type;

            while ((null != parent) && (null == namespace)

                    && (((type = parent.getNodeType()) == Node.ELEMENT_NODE)

                    || (type == Node.ENTITY_REFERENCE_NODE))) {

                if (type == Node.ELEMENT_NODE) {

                    if (parent.getNodeName().startsWith(prefixColon))

                        return parent.getNamespaceURI();

                    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();

            }

        }

        if(prefix.equals(""))

            return "";  // default namespace

        return namespace;

    }

    public String getPrefix(String namespaceURI) {

        throw new UnsupportedOperationException();

    }

    public Iterator getPrefixes(String namespaceURI) {

        throw new UnsupportedOperationException();

    }

}