package com.dbxml.labrador.services;
/*
* The dbXML Labrador Software License, Version 1.0
*
*
* Copyright (c) 2003 The dbXML Group, L.L.C. 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
* dbXML Group, L.L.C. (http://www.dbxml.com/)."
* Alternately, this acknowledgment may appear in the software
* itself, if and wherever such third-party acknowledgments normally
* appear.
*
* 4. The names "Labrador" and "dbXML Group" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* info@dbxml.com
*
* 5. Products derived from this software may not be called "Labrador",
* nor may "Labrador" appear in their name, without prior written
* permission of The dbXML Group, L.L.C..
*
* 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 THE DBXML GROUP, L.L.C. 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.
* ====================================================================
*
* $Id: InterfaceService.java,v 1.9 2003/10/06 17:36:33 bradford Exp $
*/
import com.dbxml.labrador.Describer;
import com.dbxml.labrador.Discovery;
import com.dbxml.labrador.ID;
import com.dbxml.labrador.Resolver;
import com.dbxml.labrador.broker.Broker;
import com.dbxml.labrador.exceptions.RequestException;
import com.dbxml.labrador.objects.SimpleObject;
import java.io.IOException;
import java.io.StringWriter;
import java.util.Map;
import java.util.WeakHashMap;
/**
* InterfaceService is the Labrador interface service. It retrieves an
* Instance's Discovery interface (if it has one), and describes that
* interface to the result stream using an associated Describer.
*/
public class InterfaceService extends SimpleObject {
private static final int BUFFER_SIZE = 8192;
private static final String SERVICE_NAME = "/services/InterfaceService";
private static final ID SERVICE_ID = new ID(SERVICE_NAME);
private Map cache = new WeakHashMap();
private Object cacheMutex = new Object();
public InterfaceService() {
super(SERVICE_ID);
}
public static final String[] PARAMS_describe = {"name", "type"};
public String describe(String name, String type) throws RequestException, IOException {
ID id = new ID(name);
String key = type + ":" + id;
String result;
synchronized ( cacheMutex ) {
result = (String)cache.get(key);
}
if ( result != null )
return result;
else {
// The the Broker instance
Broker broker = Broker.getInstance();
// Get the Describer for the specified type
Describer describer = broker.getDescriber(type);
// Retrieve the best Resolver
Resolver resolver = broker.getBestResolver(id);
// Retrieve the Discovery interface from the Resolver
Discovery discovery = resolver.getDiscovery(id);
// Stream the description to the StringWriter
StringWriter sw = new StringWriter(BUFFER_SIZE);
describer.describe(id, discovery, sw);
result = sw.toString();
synchronized ( cacheMutex ) {
cache.put(key, result);
}
return result;
}
}
}