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XWork is an command-pattern framework that is used to power WebWork
as well as other applications. XWork provides an Inversion of Control
container, a powerful expression language, data type conversion,
validation, and pluggable configuration.
/*
* Copyright (c) 2002-2006 by OpenSymphony
* All rights reserved.
*/
package com.opensymphony.xwork2;
import com.opensymphony.xwork2.util.ClassLoaderUtil;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.config.entities.ActionConfig;
import com.opensymphony.xwork2.config.entities.InterceptorConfig;
import com.opensymphony.xwork2.config.entities.ResultConfig;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.Interceptor;
import com.opensymphony.xwork2.util.OgnlUtil;
import com.opensymphony.xwork2.validator.Validator;
import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import ognl.OgnlException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* ObjectFactory is responsible for building the core framework objects. Users may register their
* own implementation of the ObjectFactory to control instantiation of these Objects.
*
* This default implementation uses the {@link #buildBean(Class,java.util.Map) buildBean}
* method to create all classes (interceptors, actions, results, etc).
*
* To add lifecycle hook into an ObjectFactory, either or both of the following interfaces
* could be implemented by the ObjectFactory itself.
*
* - {@link org.apache.struts2.util.ObjectFactoryInitializable}
* - {@link org.apache.struts2.util.ObjectFactoryDestroyable}
*
* Both will be invoked during the startup and showdown of {@link org.apache.struts2.dispatcher.FilterDispatcher} through {@link org.apache.struts2.dispatcher.Dispatcher}.
*
* @author Jason Carreira
*/
public class ObjectFactory implements Serializable {
private static final Log LOG = LogFactory.getLog(ObjectFactory.class);
private transient ClassLoader ccl;
private static ThreadLocal thSelf = new ThreadLocal();
private Container container;
@Inject(value="objectFactory.classloader", required=false)
public void setClassLoader(ClassLoader cl) {
this.ccl = cl;
}
public ObjectFactory() {
}
@Inject
public void setContainer(Container container) {
this.container = container;
}
@Inject
public static void setObjectFactory(ObjectFactory factory) {
thSelf.set(factory);
}
public static ObjectFactory getObjectFactory() {
return thSelf.get();
}
/**
* Allows for ObjectFactory implementations that support
* Actions without no-arg constructors.
*
* @return true if no-arg constructor is required, false otherwise
*/
public boolean isNoArgConstructorRequired() {
return true;
}
/**
* Utility method to obtain the class matched to className. Caches look ups so that subsequent
* lookups will be faster.
*
* @param className The fully qualified name of the class to return
* @return The class itself
* @throws ClassNotFoundException
*/
public Class getClassInstance(String className) throws ClassNotFoundException {
if (ccl != null) {
return ccl.loadClass(className);
}
return ClassLoaderUtil.loadClass(className, this.getClass());
}
/**
* Build an instance of the action class to handle a particular request (eg. web request)
* @param actionName the name the action configuration is set up with in the configuration
* @param namespace the namespace the action is configured in
* @param config the action configuration found in the config for the actionName / namespace
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
* @return instance of the action class to handle a web request
* @throws Exception
*/
public Object buildAction(String actionName, String namespace, ActionConfig config, Map extraContext) throws Exception {
return buildBean(config.getClassName(), extraContext);
}
/**
* Build a generic Java object of the given type.
*
* @param clazz the type of Object to build
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
*/
public Object buildBean(Class clazz, Map extraContext) throws Exception {
return clazz.newInstance();
}
/**
* @param obj
*/
protected Object injectInternalBeans(Object obj) {
if (obj != null && container != null) {
container.inject(obj);
}
return obj;
}
/**
* Build a generic Java object of the given type.
*
* @param className the type of Object to build
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
*/
public Object buildBean(String className, Map extraContext) throws Exception {
return buildBean(className, extraContext, true);
}
/**
* Build a generic Java object of the given type.
*
* @param className the type of Object to build
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
*/
public Object buildBean(String className, Map extraContext, boolean injectInternal) throws Exception {
Class clazz = getClassInstance(className);
Object obj = buildBean(clazz, extraContext);
if (injectInternal) {
injectInternalBeans(obj);
}
return obj;
}
/**
* Builds an Interceptor from the InterceptorConfig and the Map of
* parameters from the interceptor reference. Implementations of this method
* should ensure that the Interceptor is parameterized with both the
* parameters from the Interceptor config and the interceptor ref Map (the
* interceptor ref params take precedence), and that the Interceptor.init()
* method is called on the Interceptor instance before it is returned.
*
* @param interceptorConfig the InterceptorConfig from the configuration
* @param interceptorRefParams a Map of params provided in the Interceptor reference in the
* Action mapping or InterceptorStack definition
*/
public Interceptor buildInterceptor(InterceptorConfig interceptorConfig, Map interceptorRefParams) throws ConfigurationException {
String interceptorClassName = interceptorConfig.getClassName();
Map thisInterceptorClassParams = interceptorConfig.getParams();
Map params = (thisInterceptorClassParams == null) ? new HashMap() : new HashMap(thisInterceptorClassParams);
params.putAll(interceptorRefParams);
String message;
Throwable cause;
try {
// interceptor instances are long-lived and used across user sessions, so don't try to pass in any extra context
Interceptor interceptor = (Interceptor) buildBean(interceptorClassName, null);
OgnlUtil.setProperties(params, interceptor);
interceptor.init();
return interceptor;
} catch (InstantiationException e) {
cause = e;
message = "Unable to instantiate an instance of Interceptor class [" + interceptorClassName + "].";
} catch (IllegalAccessException e) {
cause = e;
message = "IllegalAccessException while attempting to instantiate an instance of Interceptor class [" + interceptorClassName + "].";
} catch (ClassCastException e) {
cause = e;
message = "Class [" + interceptorClassName + "] does not implement com.opensymphony.xwork2.interceptor.Interceptor";
} catch (Exception e) {
cause = e;
message = "Caught Exception while registering Interceptor class " + interceptorClassName;
} catch (NoClassDefFoundError e) {
cause = e;
message = "Could not load class " + interceptorClassName + ". Perhaps it exists but certain dependencies are not available?";
}
throw new ConfigurationException(message, cause, interceptorConfig);
}
/**
* Build a Result using the type in the ResultConfig and set the parameters in the ResultConfig.
*
* @param resultConfig the ResultConfig found for the action with the result code returned
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
*/
public Result buildResult(ResultConfig resultConfig, Map extraContext) throws Exception {
String resultClassName = resultConfig.getClassName();
Result result = null;
if (resultClassName != null) {
result = (Result) buildBean(resultClassName, extraContext);
try {
OgnlUtil.setProperties(resultConfig.getParams(), result, extraContext, true);
} catch (XWorkException ex) {
Throwable reason = ex.getCause();
if (reason instanceof OgnlException)
{
// ognl exceptions could be thrown and be ok if, for example, the result uses parameters in ways other than
// as properties for the result object. For example, the redirect result from Struts 2 allows any parameters
// to be set on the result, which it appends to the redirecting url. These parameters wouldn't have a
// corresponding setter on the result object, so an OGNL exception could be thrown. Still, this is a misuse
// of exceptions, so we should look at improving it.
LOG.debug(ex.getMessage(), reason);
} else {
throw ex;
}
}
}
return result;
}
/**
* Build a Validator of the given type and set the parameters on it
*
* @param className the type of Validator to build
* @param params property name -> value Map to set onto the Validator instance
* @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
*/
public Validator buildValidator(String className, Map params, Map extraContext) throws Exception {
Validator validator = (Validator) buildBean(className, null);
OgnlUtil.setProperties(params, validator);
return validator;
}
static class ContinuationsClassLoader extends ClassLoader {
}
}