/* 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.activiti.engine.impl.bpmn.helper;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;
import org.activiti.engine.ActivitiException;
import org.activiti.engine.delegate.BpmnError;
import org.activiti.engine.delegate.DelegateExecution;
import org.activiti.engine.delegate.DelegateTask;
import org.activiti.engine.delegate.ExecutionListener;
import org.activiti.engine.delegate.JavaDelegate;
import org.activiti.engine.delegate.TaskListener;
import org.activiti.engine.impl.bpmn.behavior.AbstractBpmnActivityBehavior;
import org.activiti.engine.impl.bpmn.behavior.ServiceTaskJavaDelegateActivityBehavior;
import org.activiti.engine.impl.bpmn.parser.FieldDeclaration;
import org.activiti.engine.impl.context.Context;
import org.activiti.engine.impl.delegate.ExecutionListenerInvocation;
import org.activiti.engine.impl.delegate.TaskListenerInvocation;
import org.activiti.engine.impl.pvm.delegate.ActivityBehavior;
import org.activiti.engine.impl.pvm.delegate.ActivityExecution;
import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior;
import org.activiti.engine.impl.util.ReflectUtil;
/**
* Helper class for bpmn constructs that allow class delegation.
*
* This class will lazily instantiate the referenced classes when needed at runtime.
*
* @author Joram Barrez
* @author Falko Menge
*/
public class ClassDelegate extends AbstractBpmnActivityBehavior implements TaskListener, ExecutionListener {
protected String className;
protected List<FieldDeclaration> fieldDeclarations;
protected ExecutionListener executionListenerInstance;
protected TaskListener taskListenerInstance;
protected ActivityBehavior activityBehaviorInstance;
public ClassDelegate(String className, List<FieldDeclaration> fieldDeclarations) {
this.className = className;
this.fieldDeclarations = fieldDeclarations;
}
public ClassDelegate(Class<?> clazz, List<FieldDeclaration> fieldDeclarations) {
this(clazz.getName(), fieldDeclarations);
}
// Execution listener
public void notify(DelegateExecution execution) throws Exception {
if (executionListenerInstance == null) {
executionListenerInstance = getExecutionListenerInstance();
}
Context.getProcessEngineConfiguration()
.getDelegateInterceptor()
.handleInvocation(new ExecutionListenerInvocation(executionListenerInstance, execution));
}
protected ExecutionListener getExecutionListenerInstance() {
Object delegateInstance = instantiateDelegate(className, fieldDeclarations);
if (delegateInstance instanceof ExecutionListener) {
return (ExecutionListener) delegateInstance;
} else if (delegateInstance instanceof JavaDelegate) {
return new ServiceTaskJavaDelegateActivityBehavior((JavaDelegate) delegateInstance);
} else {
throw new ActivitiException(delegateInstance.getClass().getName()+" doesn't implement "+ExecutionListener.class+" nor "+JavaDelegate.class);
}
}
// Task listener
public void notify(DelegateTask delegateTask) {
if (taskListenerInstance == null) {
taskListenerInstance = getTaskListenerInstance();
}
try {
Context.getProcessEngineConfiguration()
.getDelegateInterceptor()
.handleInvocation(new TaskListenerInvocation(taskListenerInstance, delegateTask));
}catch (Exception e) {
throw new ActivitiException("Exception while invoking TaskListener: "+e.getMessage(), e);
}
}
protected TaskListener getTaskListenerInstance() {
Object delegateInstance = instantiateDelegate(className, fieldDeclarations);
if (delegateInstance instanceof TaskListener) {
return (TaskListener) delegateInstance;
} else {
throw new ActivitiException(delegateInstance.getClass().getName()+" doesn't implement "+TaskListener.class);
}
}
// Activity Behavior
public void execute(ActivityExecution execution) throws Exception {
if (activityBehaviorInstance == null) {
activityBehaviorInstance = getActivityBehaviorInstance(execution);
}
try {
activityBehaviorInstance.execute(execution);
} catch (BpmnError error) {
ErrorPropagation.propagateError(error, execution);
}
}
// Signallable activity behavior
public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {
if (activityBehaviorInstance == null) {
activityBehaviorInstance = getActivityBehaviorInstance(execution);
}
if (activityBehaviorInstance instanceof SignallableActivityBehavior) {
((SignallableActivityBehavior) activityBehaviorInstance).signal(execution, signalName, signalData);
} else {
throw new ActivitiException("signal() can only be called on a " + SignallableActivityBehavior.class.getName() + " instance");
}
}
protected ActivityBehavior getActivityBehaviorInstance(ActivityExecution execution) {
Object delegateInstance = instantiateDelegate(className, fieldDeclarations);
if (delegateInstance instanceof ActivityBehavior) {
return determineBehaviour((ActivityBehavior) delegateInstance, execution);
} else if (delegateInstance instanceof JavaDelegate) {
return determineBehaviour(new ServiceTaskJavaDelegateActivityBehavior((JavaDelegate) delegateInstance), execution);
} else {
throw new ActivitiException(delegateInstance.getClass().getName()+" doesn't implement "+JavaDelegate.class.getName()+" nor "+ActivityBehavior.class.getName());
}
}
// Adds properties to the given delegation instance (eg multi instance) if needed
protected ActivityBehavior determineBehaviour(ActivityBehavior delegateInstance, ActivityExecution execution) {
if (hasMultiInstanceCharacteristics()) {
multiInstanceActivityBehavior.setInnerActivityBehavior((AbstractBpmnActivityBehavior) delegateInstance);
return multiInstanceActivityBehavior;
}
return delegateInstance;
}
// --HELPER METHODS (also usable by external classes) ----------------------------------------
public static Object instantiateDelegate(Class<?> clazz, List<FieldDeclaration> fieldDeclarations) {
return instantiateDelegate(clazz.getName(), fieldDeclarations);
}
public static Object instantiateDelegate(String className, List<FieldDeclaration> fieldDeclarations) {
Object object = ReflectUtil.instantiate(className);
applyFieldDeclaration(fieldDeclarations, object);
return object;
}
public static void applyFieldDeclaration(List<FieldDeclaration> fieldDeclarations, Object target) {
if(fieldDeclarations != null) {
for(FieldDeclaration declaration : fieldDeclarations) {
applyFieldDeclaration(declaration, target);
}
}
}
public static void applyFieldDeclaration(FieldDeclaration declaration, Object target) {
Method setterMethod = ReflectUtil.getSetter(declaration.getName(),
target.getClass(), declaration.getValue().getClass());
if(setterMethod != null) {
try {
setterMethod.invoke(target, declaration.getValue());
} catch (IllegalArgumentException e) {
throw new ActivitiException("Error while invoking '" + declaration.getName() + "' on class " + target.getClass().getName(), e);
} catch (IllegalAccessException e) {
throw new ActivitiException("Illegal acces when calling '" + declaration.getName() + "' on class " + target.getClass().getName(), e);
} catch (InvocationTargetException e) {
throw new ActivitiException("Exception while invoking '" + declaration.getName() + "' on class " + target.getClass().getName(), e);
}
} else {
Field field = ReflectUtil.getField(declaration.getName(), target);
if(field == null) {
throw new ActivitiException("Field definition uses unexisting field '" + declaration.getName() + "' on class " + target.getClass().getName());
}
// Check if the delegate field's type is correct
if(!fieldTypeCompatible(declaration, field)) {
throw new ActivitiException("Incompatible type set on field declaration '" + declaration.getName()
+ "' for class " + target.getClass().getName()
+ ". Declared value has type " + declaration.getValue().getClass().getName()
+ ", while expecting " + field.getType().getName());
}
ReflectUtil.setField(field, target, declaration.getValue());
}
}
public static boolean fieldTypeCompatible(FieldDeclaration declaration, Field field) {
if(declaration.getValue() != null) {
return field.getType().isAssignableFrom(declaration.getValue().getClass());
} else {
// Null can be set any field type
return true;
}
}
/**
* returns the class name this {@link ClassDelegate} is configured to. Comes in handy if you want to
* check which delegates you already have e.g. in a list of listeners
*/
public String getClassName() {
return className;
}
}