--- /dev/null
+/*
+ * Copyright (C) 2007-2012 Argeo GmbH
+ *
+ * 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.argeo.slc.core.execution;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.argeo.slc.SlcException;
+import org.argeo.slc.UnsupportedException;
+import org.argeo.slc.execution.ExecutionContext;
+import org.argeo.slc.execution.ExecutionFlow;
+import org.argeo.slc.execution.ExecutionSpec;
+import org.argeo.slc.execution.ExecutionStack;
+import org.springframework.beans.factory.ObjectFactory;
+import org.springframework.beans.factory.config.Scope;
+
+/**
+ * When Spring beans are instantiated with this scope, the same instance is
+ * reused across an execution.
+ */
+public class ExecutionScope implements Scope {
+ private final static Log log = LogFactory.getLog(ExecutionScope.class);
+
+ private final ThreadLocal<ExecutionStack> executionStack = new ThreadLocal<ExecutionStack>();
+ public final ThreadLocal<String> executionStackBeanName = new ThreadLocal<String>();
+
+ private final ThreadLocal<ExecutionContext> executionContext = new ThreadLocal<ExecutionContext>();
+ private final ThreadLocal<String> executionContextBeanName = new ThreadLocal<String>();
+
+ public Object get(String name, ObjectFactory objectFactory) {
+ if (log.isTraceEnabled())
+ log.debug("Get execution scoped bean " + name);
+
+ // shortcuts
+ if (executionStackBeanName.get() != null
+ && name.equals(executionStackBeanName.get())) {
+ return executionStack.get();
+ }
+
+ if (executionContextBeanName.get() != null
+ && name.equals(executionContextBeanName.get())) {
+ return executionContext.get();
+ }
+
+ // execution context must be defined first
+ if (executionContext.get() == null) {
+ Object obj = objectFactory.getObject();
+ if (obj instanceof ExecutionContext) {
+ return dealWithSpecialScopedObject(name, executionContext,
+ executionContextBeanName, (ExecutionContext) obj);
+ } else {
+ // TODO: use execution context wrapper
+ throw new SlcException("No execution context has been defined.");
+ }
+ }
+
+ // for other scoped objects, an executions stack must be available
+ if (executionStack.get() == null) {
+ Object obj = objectFactory.getObject();
+ if (obj instanceof ExecutionStack) {
+ return dealWithSpecialScopedObject(name, executionStack,
+ executionStackBeanName, (ExecutionStack) obj);
+ } else {
+ throw new SlcException("No execution stack has been defined.");
+ }
+ }
+
+ // see if the execution stack already knows the object
+ Object obj = executionStack.get().findScopedObject(name);
+ if (obj == null) {
+ obj = objectFactory.getObject();
+ if (obj instanceof ExecutionContext)
+ throw new SlcException(
+ "Only one execution context can be defined per thread");
+ if (obj instanceof ExecutionStack)
+ throw new SlcException(
+ "Only one execution stack can be defined per thread");
+
+ checkForbiddenClasses(obj);
+
+ executionStack.get().addScopedObject(name, obj);
+ }
+ return obj;
+
+ }
+
+ protected <T> T dealWithSpecialScopedObject(String name,
+ ThreadLocal<T> threadLocal,
+ ThreadLocal<String> threadLocalBeanName, T newObj) {
+
+ T obj = threadLocal.get();
+ if (obj == null) {
+ obj = newObj;
+ threadLocal.set(obj);
+ threadLocalBeanName.set(name);
+ if (log.isTraceEnabled()) {
+ log.debug(obj.getClass() + " instantiated. (beanName=" + name
+ + ")");
+ }
+ return obj;
+ } else {
+ throw new SlcException("Only one scoped " + obj.getClass()
+ + " can be defined per thread");
+ }
+
+ }
+
+ protected void checkForbiddenClasses(Object obj) {
+ Class<?> clss = obj.getClass();
+ if (ExecutionFlow.class.isAssignableFrom(clss)
+ || ExecutionSpec.class.isAssignableFrom(clss)) {
+ throw new UnsupportedException("Execution scoped object", clss);
+ }
+ }
+
+ public String getConversationId() {
+ // TODO: is it the most relevant?
+ return executionContext.get().getUuid();
+ }
+
+ public void registerDestructionCallback(String name, Runnable callback) {
+ if (Thread.currentThread() instanceof ExecutionThread) {
+ ExecutionThread executionThread = (ExecutionThread) Thread
+ .currentThread();
+ executionThread.registerDestructionCallback(name, callback);
+ }
+ }
+
+ public Object remove(String name) {
+ if (log.isDebugEnabled())
+ log.debug("Remove object " + name);
+ throw new UnsupportedOperationException();
+ }
+
+ public Object resolveContextualObject(String key) {
+ return executionContext.get().getVariable(key);
+ }
+
+}
projects / gpl / argeo-slc.git / blobdiff