discoveryconfigadv.java

jxta平台的开发包

/*
 * Copyright (c) 2004 Sun Microsystems, Inc.  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. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    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.
 * ====================================================================
 *
 * 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.
 *
 * $Id: DiscoveryConfigAdv.java,v 1.4 2006/05/30 20:53:50 hamada Exp $
 */

package net.jxta.impl.protocol;

import java.net.URI;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;

import net.jxta.document.Advertisement;
import net.jxta.document.AdvertisementFactory;
import net.jxta.document.Attributable;
import net.jxta.document.Attribute;
import net.jxta.document.Document;
import net.jxta.document.Element;
import net.jxta.document.ExtendableAdvertisement;
import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredDocument;
import net.jxta.document.XMLElement;
import net.jxta.id.ID;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * Contains parameters for configuration of the Reference Implemenation
 * Rendezvous Service.
 *
 * <p/><pre><code>
 *
 * </code></pre>
 *
 */
public final class DiscoveryConfigAdv extends ExtendableAdvertisement {

    /**
     *  Instantiator for DiscoveryConfigAdv
     */
    public static class Instantiator implements AdvertisementFactory.Instantiator {

        /**
         * {@inheritDoc}
         */
        public String getAdvertisementType( ) {
            return advType;
        }

        /**
         * {@inheritDoc}
         */
        public Advertisement newInstance( ) {
            return new DiscoveryConfigAdv();
        }

        /**
         * {@inheritDoc}
         */
        public Advertisement newInstance(Element root) {
            return new DiscoveryConfigAdv( root );
        }
    };

    /**
     *  Log4J Logger
     */
    private static final Logger LOG = Logger.getLogger(DiscoveryConfigAdv.class.getName());


    /**
     *  Our DOCTYPE
     */
    private static final String advType =  "jxta:DiscoConfigAdv";

    private static final String FORWARD_ALWAYS_REPLICA = "forwardAlwaysReplica";
    private static final String FORWARD_BELOW_TRESHOLD = "forwardBelowThreshold";
    private static final String LOCAL_ONLY = "localOnly";

    private static final String [] fields = { };

    /**
     * If true, the discovery service will always forward queries to the replica peer
     * even if there are local responses, unless the replica peer is the local peer.
     */
    private boolean forwardAlwaysReplica = false;

    /**
     * If true, the discovery service will always forward queries if the number of local
     * responses is below the specified threshold. The threshold may be reduced by the number
     * of local responses before forwarding. NOTE: not yet implemented.
     */
    private boolean forwardBelowTreshold = false;

    /**
     * localOnly discovery.
     */
    private boolean localOnly = false;

    /**
     *  Returns the identifying type of this Advertisement.
     *
     *  <p/><b>Note:</b> This is a static method. It cannot be used to determine
     *  the runtime type of an advertisment. ie.
     *  </p><code><pre>
     *      Advertisement adv = module.getSomeAdv();
     *      String advType = adv.getAdvertisementType();
     *  </pre></code>
     *
     *  <p/><b>This is wrong and does not work the way you might expect.</b>
     *  This call is not polymorphic and calls
     *  Advertiement.getAdvertisementType() no matter what the real type of the
     *  advertisment.
     *
     * @return String the type of advertisement
     */
    public static String getAdvertisementType() {
        return advType ;
    }

    /**
     *  Use the Instantiator through the factory
     */
    DiscoveryConfigAdv() {}

    /**
     *  Use the Instantiator through the factory
     */
    DiscoveryConfigAdv(Element root) {
        if( !XMLElement.class.isInstance( root ) )
            throw new IllegalArgumentException( getClass().getName() + " only supports XLMElement" );

        XMLElement doc = (XMLElement) root;

        String doctype = doc.getName();

        String typedoctype = "";
        Attribute itsType = doc.getAttribute( "type" );
        if( null != itsType )
            typedoctype = itsType.getValue();

        if( !doctype.equals(getAdvertisementType()) && !getAdvertisementType().equals(typedoctype) ) {
            throw new IllegalArgumentException( "Could not construct : "
                                                + getClass().getName() + "from doc containing a " + doc.getName() );
        }

        Enumeration eachAttr = doc.getAttributes();

        while (eachAttr.hasMoreElements()) {
            Attribute aDiscoAttr = (Attribute) eachAttr.nextElement();
            String name = aDiscoAttr.getName();
            boolean flag = Boolean.valueOf(aDiscoAttr.getValue().trim()).booleanValue();

            if( FORWARD_ALWAYS_REPLICA.equals(name) ) {
                forwardAlwaysReplica = flag;
            } else if ( FORWARD_BELOW_TRESHOLD.equals(name) ) {
                forwardBelowTreshold = flag;
            } else if ( LOCAL_ONLY.equals(name) ) {
                localOnly = flag;
            } else {
                if ( LOG.isEnabledFor(Level.WARN) ) {
                    LOG.warn( "Unhandled Attribute: " + name );
                }
            }
        }
    }

    /**
     * Make a safe clone of this DiscoveryConfigAdv.
     *
     * @return Object A copy of this DiscoveryConfigAdv
     */
    public Object clone() {

        DiscoveryConfigAdv result = new DiscoveryConfigAdv();

        return result;
    }

    /**
     * {@inheritDoc}
     */
    public String getAdvType() {
        return getAdvertisementType();
    }

    /**
     * {@inheritDoc}
     */
    public final String getBaseAdvType() {
        return getAdvertisementType();
    }

    /**
     *  {@inheritDoc}
     */
    public ID getID() {
        return ID.nullID;
    }

    /**
     *  {@inheritDoc}
     */
    public Document getDocument( MimeMediaType encodeAs ) {
        StructuredDocument adv = (StructuredDocument) super.getDocument( encodeAs );

        if( adv instanceof Attributable ) {
            Attributable attrDoc = (Attributable) adv;

            // Do not output if false. It is the default value.
            if (forwardAlwaysReplica) {
                attrDoc.addAttribute( FORWARD_ALWAYS_REPLICA, Boolean.toString(forwardAlwaysReplica) );
            }
            if (forwardBelowTreshold) {
                attrDoc.addAttribute( FORWARD_BELOW_TRESHOLD, Boolean.toString(forwardBelowTreshold) );
            }
            if (localOnly) {
                attrDoc.addAttribute( FORWARD_BELOW_TRESHOLD, Boolean.toString(localOnly) );
            }
        }
        return adv;
    }

    /**
     *  {@inheritDoc}
     */
    public String [] getIndexFields() {
        return fields;
    }

    /**
     * True if this discovery service will forward queries to the replica peer in all cases, rather
     * than only in the absence of local responses.
     *
     * @return The current setting.
     */
    public boolean getForwardAlwaysReplica() {
        return forwardAlwaysReplica;
    }

    /**
     * Specifies if this discovery service will forward queries to the replica peer in all cases, rather than only in the absence
     * of local responses.
     *
     * @param newvalue The new setting.
     */
    public void setForwardAlwaysReplica(boolean newvalue) {
        forwardAlwaysReplica = newvalue;
    }

    /**
     * True if this discovery service will forward queries when the number of local responses
     * is below the specified treshold, rather than only in the absence of local responses.
     *
     * @return The current setting.
     */
    public boolean getForwardBelowTreshold() {
        return forwardBelowTreshold;
    }

    /**
     * Specifies if this discovery service will forward queries when the number of local responses is below the specified
     * treshold, rather than only in the absence of local responses.
     *
     * @param newvalue The new setting.
     */
    public void setForwardBelowTreshold(boolean newvalue) {
        forwardBelowTreshold = newvalue;
    }

    /**
     * True if this discovery service performs only local discovery.
     *
     * @return The current setting.
     */
    public boolean getLocalOnly() {
        return localOnly;
    }

    /**
     * Specifies if this discovery service will perform local only discovery.
     *
     * @param newvalue The new setting.
     */
    public void setLocalOnly(boolean newvalue) {
        localOnly = newvalue;
    }
}