/*
* Copyright 2002-2014 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.web.socket.server.standard;
import java.util.Arrays;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.websocket.server.ServerEndpoint;
import javax.websocket.server.ServerEndpointConfig.Configurator;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.stereotype.Component;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.WebApplicationContext;
/**
* A {@link javax.websocket.server.ServerEndpointConfig.Configurator} for initializing
* {@link ServerEndpoint}-annotated classes through Spring.
*
* <p>
* <pre class="code">
* @ServerEndpoint(value = "/echo", configurator = SpringConfigurator.class)
* public class EchoEndpoint {
* // ...
* }
* </pre>
*
* @author Rossen Stoyanchev
* @since 4.0
* @see ServerEndpointExporter
*/
public class SpringConfigurator extends Configurator {
private static final String NO_VALUE = ObjectUtils.identityToString(new Object());
private static final Log logger = LogFactory.getLog(SpringConfigurator.class);
private static final Map<String, Map<Class<?>, String>> cache =
new ConcurrentHashMap<String, Map<Class<?>, String>>();
@SuppressWarnings("unchecked")
@Override
public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException {
WebApplicationContext wac = ContextLoader.getCurrentWebApplicationContext();
if (wac == null) {
String message = "Failed to find the root WebApplicationContext. Was ContextLoaderListener not used?";
logger.error(message);
throw new IllegalStateException(message);
}
String beanName = ClassUtils.getShortNameAsProperty(endpointClass);
if (wac.containsBean(beanName)) {
T endpoint = wac.getBean(beanName, endpointClass);
if (logger.isTraceEnabled()) {
logger.trace("Using @ServerEndpoint singleton " + endpoint);
}
return endpoint;
}
Component annot = AnnotationUtils.findAnnotation(endpointClass, Component.class);
if ((annot != null) && wac.containsBean(annot.value())) {
T endpoint = wac.getBean(annot.value(), endpointClass);
if (logger.isTraceEnabled()) {
logger.trace("Using @ServerEndpoint singleton " + endpoint);
}
return endpoint;
}
beanName = getBeanNameByType(wac, endpointClass);
if (beanName != null) {
return (T) wac.getBean(beanName);
}
if (logger.isTraceEnabled()) {
logger.trace("Creating new @ServerEndpoint instance of type " + endpointClass);
}
return wac.getAutowireCapableBeanFactory().createBean(endpointClass);
}
private String getBeanNameByType(WebApplicationContext wac, Class<?> endpointClass) {
String wacId = wac.getId();
Map<Class<?>, String> beanNamesByType = cache.get(wacId);
if (beanNamesByType == null) {
beanNamesByType = new ConcurrentHashMap<Class<?>, String>();
cache.put(wacId, beanNamesByType);
}
if (!beanNamesByType.containsKey(endpointClass)) {
String[] names = wac.getBeanNamesForType(endpointClass);
if (names.length == 1) {
beanNamesByType.put(endpointClass, names[0]);
}
else {
beanNamesByType.put(endpointClass, NO_VALUE);
if (names.length > 1) {
throw new IllegalStateException("Found multiple @ServerEndpoint's of type [" +
endpointClass.getName() + "]: bean names " + Arrays.asList(names));
}
}
}
String beanName = beanNamesByType.get(endpointClass);
return (NO_VALUE.equals(beanName) ? null : beanName);
}
}