/* * Copyright (c) 2001-2007 Sun Microsystems, Inc.  All rights reserved. *   *  The Sun Project JXTA(TM) Software License *   *  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. The end-user documentation included with the redistribution, if any, must  *     include the following acknowledgment: "This product includes software  *     developed by Sun Microsystems, Inc. for JXTA(TM) technology."  *     Alternately, this acknowledgment may appear in the software itself, if  *     and wherever such third-party acknowledgments normally appear. *   *  4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must  *     not be used to endorse or promote products derived from this software  *     without prior written permission. For written permission, please contact  *     Project JXTA at http://www.jxta.org. *   *  5. Products derived from this software may not be called "JXTA", nor may  *     "JXTA" appear in their name, without prior written permission of Sun. *   *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 SUN  *  MICROSYSTEMS OR ITS 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. *   *  JXTA is a registered trademark of Sun Microsystems, Inc. in the United  *  States and other countries. *   *  Please see the license information page at : *  <http://www.jxta.org/project/www/license.html> for instructions on use of  *  the license in source files. *   *  ==================================================================== *   *  This software consists of voluntary contributions made by many individuals  *  on behalf of Project JXTA. For more information on Project JXTA, please see  *  http://www.jxta.org. *   *  This license is based on the BSD license adopted by the Apache Foundation.  */package net.jxta.document;/** * Extendable advertisements provide features for allowing inheritance of * advertisement types. The core and standard JXTA advertisements all allow * extension by extending this class. * * @see net.jxta.document.Advertisement * @see net.jxta.document.AdvertisementFactory * @see net.jxta.document.Document * @see net.jxta.document.MimeMediaType */public abstract class ExtendableAdvertisement extends Advertisement {    /**     *  If {@code true} then the advertisement will be pretty print formatted     *  when it is output as XML. Currently this must be specified at      *  construction time as it is normally a preference per advertisement type.     */    private transient boolean formatted;        /**     *  Default constructor. The advertisement will *not* be pretty-printed when     *  it is output as XML.     */    protected ExtendableAdvertisement() {        this(false);    }        /**     *  @param formatted If {@code true} then the advertisement will be pretty      *  print formatted when it is output as XML.     */    protected ExtendableAdvertisement(boolean formatted) {        this.formatted = formatted;    }        /**     * Returns the base type of this advertisement hierarchy. Typically, only     * the most basic advertisement of a type will implement this method and     * declare it as <code>final</code>.     *     * @return String the base type of advertisements in this hierarchy.     */    public abstract String getBaseAdvType();    /**     * Process an individual element from the document during parse. Normally,     * implementations will allow the base advertisements a chance to handle     * the element before attempting to handle the element themselves. ie.     * <p/>     * <pre><code>     *  protected boolean handleElement(Element elem) {     *     *      if (super.handleElement()) {     *           // it's been handled.     *           return true;     *           }     *      <i>... handle elements here ...</i>     *     *      // we don't know how to handle the element     *      return false;     *      }     *  </code></pre>     *     * @param elem The element to be processed.     * @return {@code true} if the element was recognized, otherwise false.     */    protected boolean handleElement(Element elem) {        // we don't handle any elements.        return false;    }    /**     * Process an individual attribute from the document root node. Normally,     * implementations will allow the base advertisements a chance to handle     * the attribute before attempting to handle the element themselves. ie.     * <p/>     * <p/><pre><code>     *  protected boolean handleAttribute( Attribute elem ) {     * <p/>     *      if (super.handleAttribute()) {     *           // it's been handled.     *           return true;     *           }     *     *      <i>... handle attributes here ...</i>     *     *      // we don't know how to handle the attribute     *      return false;     *      }     *  </code></pre>     *     * @param attrib The attribute to be processed.     * @return {@code true} if the attribute was recognized, otherwise false.     */    protected boolean handleAttribute(Attribute attrib) {        // "handle" the attributes that we choose to ignore.        if ("xmlns:jxta".equals(attrib.getName())) {            return true;        } else if ("xml:space".equals(attrib.getName())) {            return true;        } else if ("type".equals(attrib.getName())) {            return true;        }        return false;    }    /**     * {@inheritDoc}     * <p/>     * We don't have any content to add, just build the document instance and      * return it to implementations that actually do something with it.     */    @Override    public Document getDocument(MimeMediaType encodeAs) {        Document adv = StructuredDocumentFactory.newStructuredDocument(encodeAs, getBaseAdvType());        if (!(adv instanceof Attributable)) {            throw new IllegalArgumentException("Advertisements require document type with attribute support.");        }        if (adv instanceof XMLDocument) {            XMLDocument xmlAdv = (XMLDocument) adv;            xmlAdv.addAttribute("xmlns:jxta", "http://jxta.org");            if (!formatted) {                xmlAdv.addAttribute("xml:space", "preserve");            }        }        if (!getBaseAdvType().equals(getAdvType())) {            ((Attributable) adv).addAttribute("type", getAdvType());        }                return adv;    }}