DefaultConversationService.java

/**
 * Copyright 2010 CosmoCode GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.cosmocode.palava.ipc.conversation;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;
import com.google.inject.Inject;
import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.name.Names;

import de.cosmocode.palava.ipc.IpcSession;

/**
 * Default {@link ConversationService} implementation.
 *
 * @since 1.4
 * @author Willi Schoenborn
 */
final class DefaultConversationService implements ConversationService {

    private static final Logger LOG = LoggerFactory.getLogger(DefaultConversationService.class);

    private final Provider<IpcSession> currentSession;
    
    @Inject
    public DefaultConversationService(Provider<IpcSession> currentSession) {
        this.currentSession = Preconditions.checkNotNull(currentSession, "CurrentSession");
    }

    @Override
    public Conversation get(String name) {
        final String key = Key.get(Conversation.class, Names.named(name)).toString();
        final IpcSession session = currentSession.get();
        final Conversation present = (Conversation) session.get(key);
        if (present == null) {
            final Conversation conversation = new DefaultConversation(session, key);
            LOG.trace("Starting new conversation {}", conversation);
            session.put(key, conversation);
            return conversation;
        } else {
            LOG.trace("Found old conversation {} in session", present);
            return present;
        }
    }

}