/*
* 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: WireFormatMessageFactory.java,v 1.1 2005/05/03 06:49:05 hamada Exp $
*/
package net.jxta.impl.endpoint;
import java.io.InputStream;
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.document.MimeMediaType;
import net.jxta.endpoint.Message;
import net.jxta.util.ClassFactory;
/**
* This class is a class factory for Wire Format Messages. This class abstracts
* The implementation of Wire Format Messages and allows for construction based
* on the MimeType of InputStreams.
*
* <p>The WireFormatMessageFactory extends the ClassFactory to register the
* various Message wire format implementations into a static hastable. The
* factory is called with the Mime type requested to create the corresponding
* Wire Format type.
*
* @see net.jxta.endpoint.Message
* @see net.jxta.impl.endpoint.WireFormatMessage
* @see net.jxta.util.ClassFactory
* @see net.jxta.document.MimeMediaType
*
*/
public class WireFormatMessageFactory extends ClassFactory {
/**
* Log4J categorgy
*/
private static final Logger LOG = Logger.getLogger(WireFormatMessageFactory.class.getName());
/**
* Interface for instantiators of wire format messages.
*/
public interface Instantiator {
/**
* Returns the list of mime types supported by this serialization. All of
* mimetypes in this list should have no mime type parameters.
*/
public MimeMediaType [] getSupportedMimeTypes();
/**
* Returns a list of the content encodings supported by this serialization.
* These content encodings apply to both the overall coding of the message
* and to the encodig of individual elements.
*/
public MimeMediaType [] getSupportedContentEncodings();
/**
* Create a WireFormatMessage from an abstract message. It is an error
* (though lazily enforced) tomodify the abstract message during the
* lifetime of the WireFormatMessage.
*
* @param msg the message for which a serialization is desired.
* @param type the the serialization form desired. This can include
* mime parameters to control options.
* @param preferedContentEncoding An array of acceptable message encodings
* in descending order of preference. any or none of these encoding options
* may be used. May be null for unencoded messages.
* @return a proxy object for the abstract message which is a
* representation of the message in its serialized form.
*/
public WireFormatMessage toWire(Message msg, MimeMediaType type, MimeMediaType [] preferedContentEncoding);
/**
* Create an abstract message from a serialization.
*
* @param is The message stream. Message serializations must either use
* internal data or EOF to determine the length of the stream.
* @param type Declared message type of the stream including any optional
* configuration parameters.
* @param contentEncoding Content encoding (including optional parameters)
* which has been applied to the message. May be null for unencoded messages.
* @return a proxy object for the abstract message which is a
* representation of the message in its serialized form.
*/
public Message fromWire(InputStream is, MimeMediaType type, MimeMediaType contentEncoding) throws IOException;
};
/**
* This is the map of mime-types and constructors used by
* <CODE>newStructuredDocument</CODE>.
*/
private Map encodings = new Hashtable();
/**
* If true then the pre-defined set of StructuredDocument sub-classes has
* been registered from the property containing them.
*/
private volatile boolean loadedProperty = false;
/**
* This class is in fact a singleton. This is the instance that backs the
* static methods.
*/
private static WireFormatMessageFactory factory = new WireFormatMessageFactory();
/**
* Private constructor. This class is not meant to be instantiated except
* by itself.
*
*/
private WireFormatMessageFactory() {}
;
/**
* 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 synchronized boolean doLoadProperty() {
if(loadedProperty)
return true;
try {
return registerFromResources("net.jxta.impl.config",
"MsgWireFmtsInstanceTypes");
} catch (MissingResourceException notFound) {
if (LOG.isEnabledFor(Level.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 Map 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 mime 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.
*/
protected boolean registerAssoc(String className) {
boolean registeredSomething = false;
if (LOG.isEnabledFor(Level.DEBUG))
LOG.debug("Registering : " + className);
try {
Class msgClass = Class.forName(className);
Instantiator instantiator = (Instantiator)
(msgClass.getField("INSTANTIATOR").get(null));
MimeMediaType [] mimeTypes = instantiator.getSupportedMimeTypes();
for(int eachType = 0; eachType < mimeTypes.length; eachType++) {
if (LOG.isEnabledFor(Level.DEBUG))
LOG.debug(" Registering Type : " + mimeTypes[eachType].getMimeMediaType());
registeredSomething |=
registerInstantiator(mimeTypes[eachType], instantiator);
}
} catch(Exception all) {
if (LOG.isEnabledFor(Level.WARN))
LOG.warn("Failed to register '" + className + "'", all);
}
return registeredSomething;
}
/**
* Register an instantiator object a mime-type of documents to be
* constructed.
*
* @param mimetype the mime-type associated.
* @param instantiator the instantiator that wants to be registered..
* @return boolean true if the instantiator for this mime-type is now
* registered. If there was already an instantiator this mime-type then
* false will be returned.
* @throws SecurityException there were permission problems registering
* the instantiator.
*/
public static boolean registerInstantiator(
MimeMediaType mimetype,
Instantiator instantiator) {
boolean registered = factory.registerAssoc(mimetype.getMimeMediaType(),
instantiator);
return registered;
}
/**
* Constructs an instance of {@link WireFormatMessage} matching the type
* specified by the <CODE>type</CODE> parameter.
*
* @param msg the message for which a serialization is desired.
* @param type the the serialization form desired. This can include
* mime parameters to control options.
* @param preferedEncodings An array of acceptable message encodings
* in descending order of preference. any or none of these encoding options
* may be used. May be null for unencoded messages.
* @return a proxy object for the abstract message which is a
* representation of the message in its serialized form.
*/
public static WireFormatMessage toWire(Message msg, MimeMediaType type, MimeMediaType [] preferedEncodings) {
if(!factory.loadedProperty) {
factory.loadedProperty = factory.doLoadProperty();
}
Instantiator instantiator =
(Instantiator) factory.getInstantiator(type.getMimeMediaType());
return instantiator.toWire(msg, type, preferedEncodings);
}
/**
* Constructs an instance of <CODE>MessageWireFormat</CODE> matching the type
* specified by the <CODE>type</CODE> parameter.
*
* @param is The message stream. Message serializations must either use
* internal data or EOF to determine the length of the stream.
* @param type Declared message type of the stream including any optional
* configuration parameters.
* @param contentEncoding Content encoding (including optional parameters)
* which has been applied to the message. May be null for unencoded messages.
* @return the new abstract message.
*/
public static Message fromWire(InputStream is, MimeMediaType type, MimeMediaType contentEncoding) throws IOException {
if(!factory.loadedProperty) {
factory.loadedProperty = factory.doLoadProperty();
}
Instantiator instantiator =
(Instantiator) factory.getInstantiator(type.getMimeMediaType());
return instantiator.fromWire(is, type, contentEncoding);
}
}
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