Java tutorial
/** * Copyright 2002-2015 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 ch.rasc.wampspring.config; import java.util.HashMap; import java.util.Map; import org.apache.commons.logging.LogFactory; import org.springframework.util.StringUtils; import org.springframework.web.socket.WebSocketSession; /** * @author Rossen Stoyanchev * @author Ralph Schaer */ public class WampSession { private final static String PREFIXES = WampSession.class.getName() + ".PREFIXES"; private final static String AUTH_KEY = WampSession.class.getName() + ".AUTH_KEY"; private final static String CHALLENGE = WampSession.class.getName() + ".CHALLENGE"; private final static String SIGNATURE = WampSession.class.getName() + ".SIGNATURE"; /** Key for the mutex session attribute */ public static final String SESSION_MUTEX_NAME = WampSession.class.getName() + ".MUTEX"; /** Key set after the session is completed */ public static final String SESSION_COMPLETED_NAME = WampSession.class.getName() + ".COMPLETED"; /** Prefix for the name of session attributes used to store destruction callbacks. */ public static final String DESTRUCTION_CALLBACK_NAME_PREFIX = WampSession.class.getName() + ".DESTRUCTION_CALLBACK."; private final WebSocketSession webSocketSession; public WampSession(WebSocketSession webSocketSession) { this.webSocketSession = webSocketSession; } /** * Return the value for the attribute of the given name, if any. * @param name the name of the attribute * @return the current attribute value, or {@code null} if not found */ @SuppressWarnings("unchecked") public <T> T getAttribute(String name) { return (T) this.webSocketSession.getAttributes().get(name); } public WebSocketSession getWebSocketSession() { return this.webSocketSession; } /** * Set the value with the given name replacing an existing value (if any). * @param name the name of the attribute * @param value the value for the attribute */ public void setAttribute(String name, Object value) { this.webSocketSession.getAttributes().put(name, value); } /** * Remove the attribute of the given name, if it exists. * <p> * Also removes the registered destruction callback for the specified attribute, if * any. However it <i>does not</i> execute</i> the callback. It is assumed the removed * object will continue to be used and destroyed independently at the appropriate * time. * @param name the name of the attribute */ public void removeAttribute(String name) { this.webSocketSession.getAttributes().remove(name); removeDestructionCallback(name); } /** * Retrieve the names of all attributes. * @return the attribute names as String array, never {@code null} */ public String[] getAttributeNames() { return StringUtils.toStringArray(this.webSocketSession.getAttributes().keySet()); } /** * Register a callback to execute on destruction of the specified attribute. The * callback is executed when the session is closed. * @param name the name of the attribute to register the callback for * @param callback the destruction callback to be executed */ public void registerDestructionCallback(String name, Runnable callback) { synchronized (getSessionMutex()) { if (isSessionCompleted()) { throw new IllegalStateException("Session id=" + getWebSocketSessionId() + " already completed"); } setAttribute(DESTRUCTION_CALLBACK_NAME_PREFIX + name, callback); } } private void removeDestructionCallback(String name) { synchronized (getSessionMutex()) { this.webSocketSession.getAttributes().remove(DESTRUCTION_CALLBACK_NAME_PREFIX + name); } } /** * Return an id for the associated WebSocket session. * @return the session id as String (never {@code null}) */ public String getWebSocketSessionId() { return this.webSocketSession.getId(); } /** * Expose the object to synchronize on for the underlying session. * @return the session mutex to use (never {@code null}) */ public Object getSessionMutex() { Object mutex = getAttribute(SESSION_MUTEX_NAME); if (mutex == null) { mutex = this.webSocketSession.getAttributes(); } return mutex; } /** * Whether the {@link #sessionCompleted()} was already invoked. */ public boolean isSessionCompleted() { return getAttribute(SESSION_COMPLETED_NAME) != null; } /** * Invoked when the session is completed. Executed completion callbacks. */ public void sessionCompleted() { synchronized (getSessionMutex()) { if (!isSessionCompleted()) { executeDestructionCallbacks(); setAttribute(SESSION_COMPLETED_NAME, Boolean.TRUE); } } } private void executeDestructionCallbacks() { for (Map.Entry<String, Object> entry : this.webSocketSession.getAttributes().entrySet()) { if (entry.getKey().startsWith(DESTRUCTION_CALLBACK_NAME_PREFIX)) { try { ((Runnable) entry.getValue()).run(); } catch (Throwable ex) { LogFactory.getLog(getClass()).error("Uncaught error in session attribute destruction callback", ex); } } } } public boolean isAuthRequested() { return getAuthKey() != null; } public boolean isAuthenticated() { return getSignature() != null; } public String getAuthKey() { return getAttribute(AUTH_KEY); } public void setAuthKey(String authKey) { setAttribute(AUTH_KEY, authKey); } public String getChallenge() { return getAttribute(CHALLENGE); } public void setChallenge(String challenge) { setAttribute(CHALLENGE, challenge); } public String getSignature() { return getAttribute(SIGNATURE); } public void setSignature(String signature) { setAttribute(SIGNATURE, signature); } public void addPrefix(String prefix, String uri) { Map<String, String> prefixes = getPrefixes(); if (prefixes == null) { prefixes = new HashMap<>(); setAttribute(PREFIXES, prefixes); } prefixes.put(prefix, uri); } public boolean hasPrefixes() { Map<String, String> prefixes = getPrefixes(); return prefixes == null || prefixes.isEmpty(); } public String getPrefix(String curie) { Map<String, String> prefixes = getPrefixes(); if (prefixes != null) { return prefixes.get(curie); } return null; } public Map<String, String> getPrefixes() { return getAttribute(PREFIXES); } }