/*
* Copyright 2004-2012 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.scope;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.config.Scope;
import org.springframework.webflow.core.collection.MutableAttributeMap;
import org.springframework.webflow.execution.RequestContext;
import org.springframework.webflow.execution.RequestContextHolder;
/**
* Base class for {@link Scope} implementations that access a Web Flow scope from the current request.
*
* @author Keith Donald
*/
public abstract class AbstractWebFlowScope implements Scope {
/**
* Logger, usable by subclasses.
*/
protected final Log logger = LogFactory.getLog(getClass());
public Object get(String name, ObjectFactory<?> objectFactory) {
MutableAttributeMap<Object> scope = getScope();
Object scopedObject = scope.get(name);
if (scopedObject == null) {
if (logger.isDebugEnabled()) {
logger.debug("No scoped instance '" + name + "' found; creating new instance");
}
scopedObject = objectFactory.getObject();
scope.put(name, scopedObject);
} else {
if (logger.isDebugEnabled()) {
logger.debug("Returning scoped instance '" + name + "'");
}
}
return scopedObject;
}
public Object remove(String name) {
return getScope().remove(name);
}
/**
* Template method that returns the target scope map.
* @throws IllegalStateException if the scope could not be accessed
*/
protected abstract MutableAttributeMap<Object> getScope() throws IllegalStateException;
/**
* Always returns <code>null</code> as most Spring Web Flow scopes do not have obvious conversation ids. Subclasses
* should override this method where conversation ids can be intelligently returned.
* @return always returns <code>null</code>
*/
public String getConversationId() {
return null;
}
public Object resolveContextualObject(String key) {
return null;
}
/**
* Will not register a destruction callback as Spring Web Flow does not support destruction of scoped beans.
* Subclasses should override this method where where destruction can adequately be accomplished.
* @param name the name of the bean to register the callback for
* @param callback the callback to execute
*/
public void registerDestructionCallback(String name, Runnable callback) {
logger.warn("Destruction callback for '" + name + "' was not registered. Spring Web Flow does not "
+ "support destruction of scoped beans.");
}
protected RequestContext getRequiredRequestContext() {
RequestContext context = RequestContextHolder.getRequestContext();
if (context == null) {
throw new IllegalStateException(
"No request context bound to this thread; to access flow-scoped beans you must be running in a flow execution request");
}
return context;
}
}