messagewireformatfactory.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

/*
 * 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
 * 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: MessageWireFormatFactory.java,v 1.2 2002/03/04 21:42:57 echtcherbina Exp $
 */

package net.jxta.impl.endpoint;


import java.io.InputStream;
import java.lang.reflect.Method;
import java.util.Hashtable;

import java.lang.reflect.InvocationTargetException;
import java.util.MissingResourceException;
//PDA requirement 18.02.2002
// this exception did not exist in jdk 1.1.8
// import java.lang.reflect.UndeclaredThrowableException;

import org.apache.log4j.Category; import org.apache.log4j.Priority;

import net.jxta.document.MimeMediaType;
import net.jxta.util.ClassFactory;

import net.jxta.impl.endpoint.MessageWireFormat;


/**
 * This class is a class factory for Advertisements. The class enables to hide
 * the implementation used to represent and create advertisements.
 *
 * <p>Advertisements are core objects that are used to advertise a Peer, a
 * PeerGroup, a Service, or a PipeServiceImpl. The Advertisement class provides a platform
 * independent representation of core objects that can be exchanged between
 * different implementations (Java, C).
 *
 * <p>The AdvertisementFactory extends the ClassFactory to register the various
 * types of adverstisements into a static hastable. The factory is called with
 * the Advertisement type requested to create the corresponding advertisement
 * type.
 *
 * @see net.jxta.document.Advertisement
 * @see net.jxta.document.Document
 * @see net.jxta.document.MimeMediaType
 * @see net.jxta.peergroup.PeerGroup
 * @see net.jxta.protocol.PeerAdvertisement
 * @see net.jxta.protocol.PeerGroupAdvertisement
 * @see net.jxta.protocol.PipeAdvertisement
 *
 * @version $Revision: 1.2 $
 * @since JXTA 1.0
 */

public class MessageWireFormatFactory extends ClassFactory {
    /**
     *  Log4J categorgy
     **/
    private static final Category LOG = Category.getInstance( MessageWireFormatFactory.class.getName());

    /**
     *  Interface for instantiators of StructuredDocuments
     **/
    public interface Instantiator {

    public MimeMediaType getOutputMimeType();

    public MessageWireFormat newInstance( MimeMediaType type );
    };

    /**
     *  This class is in fact a singleton. This is the instance that backs the
     *  static methods.
     **/
    private static MessageWireFormatFactory factory = new MessageWireFormatFactory();

    /**
     *  This is the map of mime-types and constructors used by
     *  <CODE>newStructuredDocument</CODE>.
     **/
    private Hashtable  encodings = new Hashtable();

    /**
     *  If true then the pre-defined set of StructuredDocument sub-classes has
     *  been registered from the property containing them.
     **/
    private boolean loadedProperty = false;

    /**
     *  Private constructor. This class is not meant to be instantiated except
     *  by itself.
     *
     *  @since JXTA 1.0
     **/
    private MessageWireFormatFactory() {};

    /**
     *  Registers the pre-defined set of StructuredDocument sub-classes so that
     *  this factory can construct them.
     *
     *  @return true if at least one of the StructuredDocument sub-classes could
     *  be registered otherwise false.
     **/
    private boolean doLoadProperty() {
        try {
            return registerFromResources( "net.jxta.impl.config",
            "MsgWireFmtInstanceTypes" );
        }
        catch ( MissingResourceException notFound ) {
            if (LOG.isEnabledFor(Priority.WARN)) LOG.warn( "Could not find net.jxta.impl.config properties file!" );
            return false;
        }
    }

    /**
     *  Used by ClassFactory methods to get the mapping of Mime Types to constructors.
     *
     *  @return the hashtable containing the mappings.
     **/
    protected Hashtable getAssocTable() {
        return encodings;
    }

    /**
     *  Used by ClassFactory methods to ensure that all of the instance classes
     *  which register with this factory have the correct base class
     *
     *  @return Class object of the key type.
     **/
    public Class getClassOfInstantiators() {
        // our key is the doctype names.
        return Instantiator.class;
    }

    /**
     *  Used by ClassFactory methods to ensure that all keys used with the mapping are
     *  of the correct type.
     *
     *  @return Class object of the key type.
     **/
    public Class getClassForKey() {
        // our key is the mime types.
        return String.class;
    }

    /**
     *  Register a class with the factory from its class name. We override the
     *  standard implementation to get the advertisement type from the class and
     *  use that as the key to register the class with the factory.
     *
     * @param className The class name which will be regiestered.
     * @return boolean true if the class was registered otherwise false.
     * @Exception Exception   when an error occurs.
     *
     *  @since JXTA 1.0
     */
    protected boolean registerAssoc( String className ) {
        boolean registeredSomething = false;

        try {
            Class wireFmtClass = Class.forName( className + "$Instantiator" );

            Instantiator instantiator = (Instantiator) wireFmtClass.newInstance();

            String mimeType = instantiator.getOutputMimeType().getMimeMediaType( );

            registeredSomething = registerAssoc( mimeType, instantiator );
        } catch( Exception all ) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug( "Failed to register '" + className + "'", all );
        }

        return registeredSomething;
    }

    /**
     * Register an instance class by mimetype.
     *
     * @param mimetype  the identifying value for this WireFormat instance type
     * @param instanceClass   the constructors to use in constructing objects
     *                           of this rootTypeIns type.
     * @return boolean  true if the rootType type is registered. If there is already a
     *                   constructor for this type then false will be returned.
     *
     * @exception NoSuchMethodException invalid registration
     *
     * @exception SecurityException  security error
     *
     * @version $Revision: 1.2 $
     * @since JXTA 1.0
     */
    public static boolean registerWireFormatInstance( MimeMediaType mimetype, Class instanceClass )
    throws NoSuchMethodException, SecurityException {
        boolean result = factory.registerAssoc( mimetype, instanceClass );

        return result;
    }

    /**
     * Constructs an instance of <CODE>MessageWireFormat</CODE> matching the type
     * specified by the <CODE>type</CODE> parameter.
     *
     * @param type Specifies the mime media type to be associated with the wire
     *  format instance to be created.
     * @return The instance of <CODE>MessageWireFormat</CODE> or null if it
     * could not be created.
     *
     * @version $Revision: 1.2 $
     * @since JXTA 1.0
     */

    public static MessageWireFormat newMessageWireFormat( MimeMediaType type ) {
        if( ! factory.loadedProperty )
            factory.loadedProperty = factory.doLoadProperty();

        Instantiator instantiator =
        (Instantiator) factory.getInstantiator( type.getMimeMediaType() );

        return instantiator.newInstance( type );
      }
}