ch.entwine.weblounge.common.impl.security.AccessControlParser.java Source code

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Here is the source code for ch.entwine.weblounge.common.impl.security.AccessControlParser.java

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/*
 *  Weblounge: Web Content Management System
 *  Copyright (c) 2003 - 2011 The Weblounge Team
 *  http://entwinemedia.com/weblounge
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software Foundation
 *  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

package ch.entwine.weblounge.common.impl.security;

import ch.entwine.weblounge.common.security.AccessControlList;

import org.apache.commons.io.IOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.io.Writer;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.parsers.DocumentBuilderFactory;

/**
 * Marshals and unmarshals {@link AccessControlListImpl}s to and from XML.
 */
public final class AccessControlParser {
    private static final JAXBContext jaxbContext;

    static {
        try {
            jaxbContext = JAXBContext.newInstance("ch.entwine.weblounge.security",
                    AccessControlParser.class.getClassLoader());
        } catch (JAXBException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Disallow construction of this utility class.
     */
    private AccessControlParser() {
    }

    public static AccessControlList parseAcl(String serializedForm) throws IOException {
        return parseAcl(IOUtils.toInputStream(serializedForm, "utf-8"));
    }

    /**
     * Reads an ACL from an xml input stream.
     * 
     * @param in
     *          the xml input stream
     * @return the access control list
     * @throws IOException
     *           if there is a problem reading the stream
     */
    public static AccessControlList parseAcl(InputStream in) throws IOException {
        Unmarshaller unmarshaller;
        try {
            unmarshaller = jaxbContext.createUnmarshaller();
            return unmarshaller.unmarshal(DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(in),
                    AccessControlListImpl.class).getValue();
        } catch (Throwable t) {
            throw new IOException(t);
        } finally {
            IOUtils.closeQuietly(in);
        }
    }

    /**
     * Serializes an AccessControlList to its XML form.
     * 
     * @param acl
     *          the access control list
     * @return the xml as a string
     * @throws IOException
     *           if there is a problem marshaling the xml
     */
    public static String toXml(AccessControlList acl) throws IOException {
        try {
            Marshaller marshaller = jaxbContext.createMarshaller();
            Writer writer = new StringWriter();
            marshaller.marshal(acl, writer);
            return writer.toString();
        } catch (JAXBException e) {
            throw new IOException(e);
        }
    }

}