structureddocumentfactory.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
 * 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: StructuredDocumentFactory.java,v 1.30 2005/08/12 20:06:56 bondolo Exp $
 */
package net.jxta.document;

import java.io.InputStream;
import java.io.Reader;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;

import java.io.IOException;
import java.util.MissingResourceException;

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

import net.jxta.util.ClassFactory;
import net.jxta.endpoint.MessageElement;
import net.jxta.endpoint.TextMessageElement;

/**
 * A factory for constructing instances of {@link StructuredDocument}.
 * Behind the scenes, it also provides for the registration of the mime-types
 * and constructors needed to accomplish the construction. All supported
 * mime-types will need to register their implementation in this factory.
 *
 * <p>The configuration is done via the property
 * <tt>net.jxta.impl.config.StructuredDocumentInstanceTypes</tt>
 *
 * @see         net.jxta.document.Document
 * @see         net.jxta.document.StructuredTextDocument
 * @see         net.jxta.document.StructuredDocument
 * @see         net.jxta.document.MimeMediaType
 **/
public final class StructuredDocumentFactory extends ClassFactory {
    /**
     *  Log4J categorgy
     **/
    private static final Logger LOG = Logger.getLogger( StructuredDocumentFactory.class.getName());
    
    /**
     *  Interface for instantiators of StructuredDocuments
     **/
    public interface Instantiator {
        
        /**
         *  For mapping between extensions and mime types.
         **/
        class ExtensionMapping extends Object {
            /** The extension **/
            String          extension;
            
            /** mimetype it maps to **/
            MimeMediaType   mimetype;
            
            /**
             *  disabled constructor
             **/
            private ExtensionMapping() {}
            
            /**
             *  default constructor
             **/
            public ExtensionMapping( String extension, MimeMediaType mimetype ) {
                this.extension = extension;
                this.mimetype = mimetype;
            }
            
            public boolean equals( Object target ) {
                if( this == target ) {
                    return true;
                }
                
                if( target instanceof ExtensionMapping ) {
                    ExtensionMapping asMapping = (ExtensionMapping) target;
                    return ( extension.equals( asMapping.extension ) &&
                    mimetype.equals( asMapping.mimetype ) );
                } else
                    return false;
            }
            
            public int hashCode() {
                return extension.hashCode() ^ mimetype.hashCode();
            }
            
            public String toString() {
                return extension + " -> " + mimetype.toString();
            }
            
            /**
             *  returns the extension which is part of this mapping.
             *  @return the extension which is part of this mapping.
             **/
            public String getExtension() { return extension; }
            
            /**
             *  returns the MIME Media Type which is part of this mapping.
             *  @return the MIME Media Type which is part of this mapping.
             **/
            public MimeMediaType getMimeMediaType() { return mimetype; }
        }
        
        /**
         * Returns the MIME Media types supported by this this Document per
         * {@link <a href="http://www.ietf.org/rfc/rfc2046.txt">IETF RFC 2046 <i>MIME : Media Types</i></a>}.
         *
         * <p/>JXTA does not currently support the 'Multipart' or 'Message'
         * media types.
         *
         * @return An array of MimeMediaType objects containing the MIME Media Type
         *  for this Document.
         *
         **/
        MimeMediaType [] getSupportedMimeTypes();
        
        /**
         * Returns the mapping of file extension and mime-types for this type
         * of document. The default extension is mapped to the 'null' mime-type
         * and should only be used if no other mapping matches.
         *
         * @return An array of objects containing file extensions
         *
         */
        ExtensionMapping [] getSupportedFileExtensions();
        
        /**
         * Create a new structured document of the type specified by doctype.
         *
         * @param  mimeType    The mimetype to be associated with this instance.
         *  the base type must be one of the types returned by
         *  <tt>getSupportedMimeTypes</tt>. Some implementations may accept
         *  parameters in the params section of the mimetype.
         * @param  doctype     Type for the base node of the document.
         * @return StructuredDocument instance.
         **/
        StructuredDocument newInstance( MimeMediaType mimeType, String doctype );
        
        /**
         * Create a new structured document of the type specified by doctype.
         *
         * @param  mimeType    The mimetype to be associated with this instance.
         *  The base type must be one of the types returned by
         *  <tt>getSupportedMimeTypes</tt>. Some implementations may accept
         *  parameters in the params section of the mimetype.
         * @param  doctype     Type for the base node of the document.
         * @param  value     value for the base node of the document.
         * @return {@link StructuredDocument} instance.
         **/
        StructuredDocument newInstance( MimeMediaType mimeType, String doctype, String value );
        
        /**
         *  Create a structured document from a stream containing an appropriately serialized
         *  instance of the same document.
         *
         *  @param  mimeType    The mimetype to be associated with this instance.
         *      the base type must be one of the types returned by
         * <tt>getSupportedMimeTypes</tt>. Some implementations may accept
         * parameters in the params section of the mimetype.
         *  @param  source     Inputstream from which to read the instance.
         *  @return {@link StructuredDocument} instance.
         *  @exception  IOException occurs when there is a problem with the source input stream.
         **/
        StructuredDocument newInstance( MimeMediaType mimeType, InputStream source )
        throws IOException;
    }
    
    /**
     *  Interface for instantiators of StructuredTextDocuments
     **/
    public interface TextInstantiator extends Instantiator {
      
        /**
         *  Create a structured document from a Reader containing an appropriately serialized
         *  instance of the same document.
         *
         *  @param  mimeType    The mimetype to be associated with this instance.
         *      the base type must be one of the types returned by
         * <tt>getSupportedMimeTypes</tt>. Some implementations may accept
         * parameters in the params section of the mimetype.
         *  @param  source     Reader from which to read the instance.
         *  @return {@link StructuredDocument} instance.
         *  @exception  IOException occurs when there is a problem with the source input stream.
         **/
        StructuredDocument newInstance( MimeMediaType mimeType, Reader source )
        throws IOException;
    }

      /**
     *  This class is a singleton. This is the instance that backs the
     *  static methods.
     **/
    private static StructuredDocumentFactory factory =
    new StructuredDocumentFactory();
    
    /**
     *  This is the map of mime-types and instantiators used by
     *  <CODE>newStructuredDocument</CODE>.
     **/
    private final Map  encodings = new Hashtable();
    
    /**
     *  This is the map of extensions to mime-types used by
     *  {@link #getMimeTypeForFileExtension(String) }
     **/
    private final Map  extToMime = new HashMap();
    
    /**
     *  This is the map of mime-types to extensions used by
     *  {@link #getFileExtensionForMimeType(MimeMediaType mimetype) }
     **/
    private final Map  mimeToExt = new HashMap();
    
    /**
     *  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.
     *
     **/
    private StructuredDocumentFactory() {}
    
    /**
     *  Registers the pre-defined set of StructuredDocument sub-classes so that
     *  this factory can construct them.
     *
     *  @return boolean 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",
            "StructuredDocumentInstanceTypes" );
        }
        catch ( MissingResourceException notFound ) {
            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn( "Could not find net.jxta.impl.config properties file!" );
            }