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/**
 * Copyright (c) 2009-2012, Netbout.com
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met: 1) Redistributions of source code must retain the above
 * copyright notice, this list of conditions and the following
 * disclaimer. 2) Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following
 * disclaimer in the documentation and/or other materials provided
 * with the distribution. 3) Neither the name of the NetBout.com nor
 * the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.netbout.spi.xml;

import com.jcabi.urn.URN;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import javax.xml.transform.dom.DOMSource;
import org.w3c.dom.Document;

/**
 * Parses text and builds JAXB-annotated object.
 *
 * @author Yegor Bugayenko ([email protected])
 * @version $Id$
 */
public final class JaxbParser {

    /**
     * The XML content.
     */
    private final transient String xml;

    /**
     * Public ctor.
     * @param txt The XML text
     */
    public JaxbParser(final String txt) {
        this.xml = txt;
    }

    /**
     * Do this text has this object?
     * @param type The type I'm expecting
     * @return Do we have this object inside?
     * @param  Type of input
     */
    public  boolean has(final Class type) {
        return new DomParser(this.xml).belongsTo(JaxbPrinter.namespace(type));
    }

    /**
     * Parse the text and return an object.
     * @param type The type expected
     * @param  Type to be returned
     * @return The object just unmarshalled
     */
    public  T parse(final Class type) {
        JAXBContext ctx;
        try {
            ctx = JAXBContext.newInstance(type);
        } catch (javax.xml.bind.JAXBException ex) {
            throw new IllegalArgumentException(ex);
        }
        Unmarshaller umrsh;
        try {
            umrsh = ctx.createUnmarshaller();
        } catch (javax.xml.bind.JAXBException ex) {
            throw new IllegalStateException(ex);
        }
        final Document dom = JaxbParser.clear(
            new DomParser(this.xml).parse(),
            type
        );
        T token;
        try {
            token = (T) umrsh.unmarshal(new DOMSource(dom), type).getValue();
        } catch (javax.xml.bind.JAXBException ex) {
            throw new IllegalArgumentException(ex);
        }
        return token;
    }

    /**
     * Change the namespace of the root element of this document (and
     * all its children) according to the requirements of the provided JAXB
     * type.
     * @param dom The document
     * @param type The type we're expecting
     * @return The same document
     */
    private static Document clear(final Document dom, final Class type) {
        final URN required = JaxbPrinter.namespace(type);
        if (!required.isEmpty()) {
            final String actual = dom.getDocumentElement().getNamespaceURI();
            if (!DomParser.matches(required, actual)) {
                throw new IllegalArgumentException(
                    String.format(
                        "Actual namespace is '%s' while '%s' is required",
                        actual,
                        required
                    )
                );
            }
            DomParser.rename(
                dom,
                dom.getDocumentElement(),
                actual,
                required
            );
        }
        return dom;
    }

}