relayoptimizer.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
*  Copyright (c) 2001 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
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*  2. Redistributions in binary form must reproduce the above copyright
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*  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
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*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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*  ====================================================================
*
*  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: RelayOptimizer.java,v 1.4 2006/06/08 04:31:09 gonzo Exp $
*/
package net.jxta.ext.config.optimizers;

import net.jxta.ext.config.BaseProperty;
import net.jxta.ext.config.Configurator;
import net.jxta.ext.config.Optimizer;
import net.jxta.ext.config.probes.RelayProbe;

import net.jxta.ext.http.Dispatcher;
import net.jxta.ext.http.Message;

import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.StringReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Optimiser that removes the Relay client attribute if the hosting system is
 * directly reachible from the respective {@link net.jxta.ext.service.reflection.ReflectionServlet Reflection Service}.
 *
 * @author  james todd [gonzo at jxta dot org]
 */

public class RelayOptimizer
    extends BaseOptimizer
    implements Optimizer {

    /**
     * Reflection service property key.
     */
    
    public final static String REFLECTION_SERVICE_BOOTSTRAP_KEY =
        "reflection.service.bootstrap";
    
    /**
     * Reflection service maximum wait property key.
     */
    
    public final static String REFLECTION_SERVICE_MAX_WAIT_KEY =
        "reflection.service.max_wait";

    private final static int MAX_WAIT =  7 * 1000;

    private URI bootstrap = null;
    private int max_wait = MAX_WAIT;

    /**
     * Default constructor.
     */
    
    public RelayOptimizer() {
        configure();
    }

    /**
     * Optimizer implementation that removes the Relay client attribute if the
     * hosting system is directly reachible from the respective
     * {@link net.jxta.ext.service.reflection.ReflectionServlet Reflection Service}.
     */
    
    public void optimize(Configurator configurator) {
        List reflection = this.bootstrap != null ? getReflectionServices(configurator, this.bootstrap) : null;

        if (reflection != null &&
            reflection.size() > 0) {
            RelayProbe rp = new RelayProbe(reflection, configurator.getTransports());

            configurator.setRelayOutgoing(! rp.probe());
        }
    }

    private void configure() {
        List l = getProperty(REFLECTION_SERVICE_BOOTSTRAP_KEY);

        if (l != null &&
            l.size() > 0) {
            try {
                this.bootstrap = new URI((String)l.get(0));
            } catch (URISyntaxException use) {}
        }

        l = getProperty(REFLECTION_SERVICE_MAX_WAIT_KEY);

        if (l != null &&
            l.size() > 0) {
            try {
                this.max_wait = Integer.parseInt((String)l.get(0));
            } catch (NumberFormatException nfe) {}
        }
    }

    //    private URI getBootstrap(Configurator configurator) {
    //        return configurator.getReflectionBootstrapAddress();
    //    }

    private List getReflectionServices(Configurator configurator, URI bootstrap) {
        URL u = null;

        try {
            u = bootstrap != null ? bootstrap.toURL() : null;
        } catch (MalformedURLException mue) {}

        List l = null;

        if (u != null) {
            Message results = null;

            try {
                results = new Dispatcher(u, this.max_wait).dispatch();
            } catch (IOException ioe) {}

            String s = (results != null ? results.getBody() : null);

            if (s != null) {
                StreamTokenizer st = new StreamTokenizer(new StringReader(s));
                l = new ArrayList();

                st.wordChars(' ', '~');
                st.eolIsSignificant(true);

                try {
                    while (st.nextToken() != StreamTokenizer.TT_EOF) {
                        switch (st.ttype) {
                        case StreamTokenizer.TT_WORD:
                            try {
                                l.add(new URI(st.sval.trim()));
                            } catch (URISyntaxException use) {}

                            break;
                        default:
                        }
                    }
                } catch (IOException ioe) {}
            }
        }

        return l != null ? l : Collections.EMPTY_LIST;
    }
}