/*
* Copyright 2004-2015 the original author or authors.
*
* 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 org.springframework.webflow.conversation.impl;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.webflow.conversation.Conversation;
import org.springframework.webflow.conversation.ConversationId;
import org.springframework.webflow.conversation.ConversationParameters;
import org.springframework.webflow.conversation.NoSuchConversationException;
/**
* Container for conversations that is stored in the session. When the session
* expires this container will go with it, implicitly expiring all contained
* conversations.
*
* <p>This is an internal helper class of the
* {@link SessionBindingConversationManager}.
*
* @author Erwin Vervaet
* @author Rossen Stoyanchev
*/
public class ConversationContainer implements Serializable {
private static final Log logger = LogFactory.getLog(ConversationContainer.class);
/** Maximum number of conversations in this container. -1 for unlimited. */
private int maxConversations;
/** The key of this conversation container in the session. */
private String sessionKey;
/** The contained conversations. A list of {@link ContainedConversation} objects. */
private List<ContainedConversation> conversations;
/** The sequence for unique conversation identifiers within this container. */
private int conversationIdSequence;
/**
* Create a new conversation container.
* @param maxConversations the max number of allowed concurrent conversations, -1 for unlimited
* @param sessionKey the key of this conversation container in the session
*/
public ConversationContainer(int maxConversations, String sessionKey) {
this.maxConversations = maxConversations;
this.sessionKey = sessionKey;
this.conversations = new CopyOnWriteArrayList<ContainedConversation>();
}
/**
* Return the key of this conversation container in the session.
* For package level use only.
*/
String getSessionKey() {
return sessionKey;
}
/**
* Return the current size of the conversation container:
* the number of conversations contained within it.
*/
public int size() {
return conversations.size();
}
/**
* Create a new conversation based on given parameters and add it to the container.
* @param parameters descriptive conversation parameters
* @param lock the conversation lock
* @return the created conversation
*/
public synchronized Conversation createConversation(ConversationParameters parameters, ConversationLock lock) {
ContainedConversation conversation = createContainedConversation(nextId(), lock);
conversation.putAttribute("name", parameters.getName());
conversation.putAttribute("caption", parameters.getCaption());
conversation.putAttribute("description", parameters.getDescription());
conversations.add(conversation);
if (maxExceeded()) {
if (logger.isDebugEnabled()) {
logger.debug("The max number of flow executions has been exceeded for the current user. " +
"Removing the oldest conversation with id: " + conversations.get(0).getId());
}
// end oldest conversation
conversations.get(0).end();
}
return conversation;
}
protected ConversationId nextId() {
return new SimpleConversationId(++conversationIdSequence);
}
/**
* Return the identified conversation.
* @param id the id to lookup
* @return the conversation
* @throws NoSuchConversationException if the conversation cannot be found
*/
public synchronized Conversation getConversation(ConversationId id) throws NoSuchConversationException {
for (ContainedConversation conversation : conversations) {
if (conversation.getId().equals(id)) {
return conversation;
}
}
throw new NoSuchConversationException(id);
}
protected final List<ContainedConversation> getConversations() {
return conversations;
}
/**
* Remove identified conversation from this container.
*/
public synchronized void removeConversation(ConversationId id) {
for (Iterator<ContainedConversation> it = conversations.iterator(); it.hasNext();) {
ContainedConversation conversation = it.next();
if (conversation.getId().equals(id)) {
conversations.remove(conversation);
break;
}
}
}
/**
* Has the maximum number of allowed concurrent conversations in the session been exceeded?
*/
private boolean maxExceeded() {
return maxConversations > 0 && conversations.size() > maxConversations;
}
// Hook methods
protected ContainedConversation createContainedConversation(ConversationId id, ConversationLock lock) {
return new ContainedConversation(this, id, lock);
}
}