SPR-6416, initial commit for the conversation management

org.springframework.web/src/main/java/org/springframework/web/conversation/SessionBasedConversationRepository.java

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+/*
+ * Copyright 2002-2011 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.conversation;
+
+import java.io.Serializable;
+
+import org.springframework.conversation.Conversation;
+import org.springframework.conversation.manager.AbstractConversationRepository;
+import org.springframework.conversation.manager.MutableConversation;
+import org.springframework.util.Assert;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
+
+/**
+ * A conversation store implementation ({@link org.springframework.conversation.manager.ConversationRepository}) based
+ * on a web environment where the conversations are most likely to be stored in the current session.
+ *
+ * @author Micha Kiener
+ * @since 3.1
+ */
+public class SessionBasedConversationRepository extends AbstractConversationRepository {
+
+	/** The name of the attribute for the conversation map within the session. */
+	public static final String CONVERSATION_STORE_ATTR_NAME = SessionBasedConversationRepository.class.getName();
+
+
+	public MutableConversation getConversation(String id) {
+		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
+		Object conversation = attributes
+				.getAttribute(getSessionAttributeNameForConversationId(id), RequestAttributes.SCOPE_GLOBAL_SESSION);
+		Assert.isInstanceOf(Conversation.class, conversation);
+		return (MutableConversation) conversation;
+	}
+
+	public void storeConversation(MutableConversation conversation) {
+		conversation.setId(createNextConversationId());
+		
+		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
+		String conversationSessionAttributeName = getSessionAttributeNameForConversationId(conversation.getId());
+
+		attributes.setAttribute(conversationSessionAttributeName, conversation, RequestAttributes.SCOPE_GLOBAL_SESSION);
+		attributes.registerDestructionCallback(conversationSessionAttributeName,
+				new ConversationDestructionCallback(conversation), RequestAttributes.SCOPE_GLOBAL_SESSION);
+	}
+
+	@Override
+	protected void removeSingleConversationObject(MutableConversation conversation) {
+		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
+		attributes.removeAttribute(getSessionAttributeNameForConversationId(conversation.getId()),
+				RequestAttributes.SCOPE_GLOBAL_SESSION);
+	}
+
+	protected String getSessionAttributeNameForConversationId(String conversationId) {
+		return CONVERSATION_STORE_ATTR_NAME + conversationId;
+	}
+
+	protected String createNextConversationId() {
+		int nextAvailableConversationId = 1;
+
+		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
+		synchronized (attributes.getSessionMutex()) {
+			String[] attributeNames = attributes.getAttributeNames(RequestAttributes.SCOPE_GLOBAL_SESSION);
+			for (String attributeName : attributeNames) {
+				if (attributeName.startsWith(CONVERSATION_STORE_ATTR_NAME)) {
+
+					MutableConversation conversation = (MutableConversation) attributes
+							.getAttribute(attributeName, RequestAttributes.SCOPE_GLOBAL_SESSION);
+					if (conversation.isExpired()) {
+						conversation.clear();
+						attributes.removeAttribute(attributeName, RequestAttributes.SCOPE_GLOBAL_SESSION);
+					}
+
+					String conversationId = conversation.getId();
+					int currentConversationId = Integer.parseInt(conversationId);
+					if (currentConversationId > nextAvailableConversationId) {
+						nextAvailableConversationId = currentConversationId;
+					}
+				}
+			}
+		}
+		return Integer.toString(nextAvailableConversationId);
+	}
+
+	
+	private static final class ConversationDestructionCallback implements Runnable, Serializable {
+
+		private final MutableConversation conversation;
+
+		private ConversationDestructionCallback(MutableConversation conversation) {
+			this.conversation = conversation;
+		}
+
+		public void run() {
+			conversation.clear();
+		}
+	}
+}

org.springframework.web/src/main/java/org/springframework/web/conversation/WebAwareConversationScope.java

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+/*
+ * Copyright 2002-2011 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.conversation;
+
+import org.springframework.conversation.scope.ConversationScope;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
+
+/**
+ * The extension of the default conversation scope ( {@link ConversationScope}) by supporting contextual web
+ * objects returned by overwriting {@link #resolveContextualObject(String)}.
+ *
+ * @author Micha Kiener
+ * @since 3.1
+ */
+public class WebAwareConversationScope extends ConversationScope {
+
+	/** @see org.springframework.conversation.scope.ConversationScope#resolveContextualObject(String) */
+	@Override
+	public Object resolveContextualObject(String key) {
+		// invoke super to support the conversation context objects
+		Object object = super.resolveContextualObject(key);
+		if (object != null) {
+			return object;
+		}
+
+		// support web context objects
+		RequestAttributes attributes = RequestContextHolder.currentRequestAttributes();
+		return attributes.resolveReference(key);
+	}
+}