Hi cactus team,
I checked out the cactus source from the branch '1.7_CARGO', and tried to
migrate the framework subproject to maven 2 (without the EJB, jetty and
servlet samples, documentations, integration, and the aspectj code for
logging). I saw in your mailing archive that you are also planning to use
maven 2 for cactus, so I think this may interest you.
Here is my question in details:
During the migration, the most difficult thing is that there are
cross-dependencies among different components: share-12-13-14 depends on
share-13-14 as well as j2ee-1x , while j2ee-1x depends on share-12-13-14 and
share-13-14: the share-xxx component needs an implementation of, for
example, AbstractHttpServletRequestWrapper, while such implementation, which
varies depending on the servlet spec version, is provided in the
j2ee-1xcomponent.
So I wondered, why didn't you use a factory to create those wrapper
instances, and thus get rid of those cross-dependencies?
I wrote a factory class for share-12-13-14, which creates the concrete
wrapper instances for HttpServletRequestWrapper, ServletContextWrapper,
ServletConfigWrapper and PageContextWrapper via java reflection. I also
replaced the following entries in share-12-13-14:
Those entries are..........replaced by those ones.
HttpServletRequestWrapper AbstractHttpServletWrapper
ServletContextWrapper AbstractServletContextWrapper
ServletConfigWrapper AbstractServletConfigWrapper
PageContextWrapper AbstractPageContextWrapper
In this way, the shared-12-13-14 component is completely decoupled from the
other components, and it does no longer need to know the name of the
implementation class for abstract wrappers: the implementations are
configurable.
After decoupled the components, I successfully migrated cactus framework to
maven 2. I tested the migration and everything goes on well.
But I am still not sure if I did things right. Maybe you have some strong
reasons not doing what I have done... So I would like to list the source
code of my factory class below, and listen to your opinions.
Thanks in advance.
/** ServerSideWrapperFactory.java */
package org.apache.cactus.server.factory;
import java.lang.reflect.Constructor;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.PageContext;
import org.apache.cactus.ServletURL;
import org.apache.cactus.server.AbstractHttpServletRequestWrapper;
import org.apache.cactus.server.AbstractPageContextWrapper;
import org.apache.cactus.server.AbstractServletConfigWrapper;
import org.apache.cactus.server.AbstractServletContextWrapper;
import org.apache.cactus.util.ChainedRuntimeException;
public class ServerSideWrapperFactory {
private static final String PAGE_CONTEXT_WRAPPER_IMPL =
"cactus.wrapper.impl.PageContextWrapper";
private static final String DEFAULT_PAGE_CONTEXT_WRAPPER_IMPL =
"org.apache.cactus.server.PageContextWrapper";
private static final String SERVLET_CONFIG_WRAPPER_IMPL =
"cactus.wrapper.impl.ServletConfigWrapper";
private static final String DEFAULT_SERVLET_CONFIG_WRAPPER_IMPL =
"org.apache.cactus.server.ServletConfigWrapper";
private static final String SERVLET_CONTEXT_WRAPPER_IMPL =
"cactus.wrapper.impl.ServletContextWrapper";
private static final String DEFAULT_SERVLET_CONTEXT_WRAPPER_IMPL =
"org.apache.cactus.server.ServletContextWrapper";
private static final String HTTP_SERVLET_REQUEST_WRAPPER_IMPL =
"cactus.wrapper.impl.HttpServletRequestWrapper";
private static final String DEFAULT_HTTP_SERVLET_REQUEST_WRAPPER_IMPL =
"org.apache.cactus.server.HttpServletRequestWrapper";
/** Singleton factory instance. */
private static final ServerSideWrapperFactory FACTORY =
new ServerSideWrapperFactory();
private ServerSideWrapperFactory() {
// Do nothing.
}
public static ServerSideWrapperFactory getFactory() {
return FACTORY;
}
// Public Factory Methods
--------------------------------------------------
public AbstractPageContextWrapper createPageContextWrapper(
PageContext originalContext,
ServletURL servletUrl)
throws ChainedRuntimeException {
String implClassName = System.getProperty(PAGE_CONTEXT_WRAPPER_IMPL);
if (implClassName == null || implClassName.trim().equals("")) {
implClassName = DEFAULT_PAGE_CONTEXT_WRAPPER_IMPL;
}
AbstractPageContextWrapper wrapper = null;
try {
Class clazz = Class.forName(implClassName);
Object[] args = new Object[] { originalContext, servletUrl };
Constructor constructor = clazz.getConstructor(new Class[] {
PageContext.class, ServletURL.class } );
wrapper = (AbstractPageContextWrapper)
constructor.newInstance(args);
} catch (Throwable th) {
throw new ChainedRuntimeException("Failed to create "
+ "JSP page context wrapper for Cactus.", th);
}
return wrapper;
}
public AbstractServletConfigWrapper createServletConfigWrapper(
ServletConfig originalConfig)
throws ChainedRuntimeException {
String implClassName = System.getProperty(SERVLET_CONFIG_WRAPPER_IMPL);
if (implClassName == null || implClassName.trim().equals("")) {
implClassName = DEFAULT_SERVLET_CONFIG_WRAPPER_IMPL;
}
AbstractServletConfigWrapper wrapper = null;
try {
Class clazz = Class.forName(implClassName);
Object[] args = new Object[] { originalConfig };
Constructor constructor = clazz.getConstructor(
new Class[] { ServletConfig.class} );
wrapper = (AbstractServletConfigWrapper)
constructor.newInstance(args);
} catch (Throwable th) {
throw new ChainedRuntimeException("Failed to create "
+ "servlet config wrapper for Cactus.", th);
}
return wrapper;
}
public AbstractServletContextWrapper createServletContextWrapper(
ServletContext originalContext)
throws ChainedRuntimeException {
String implClassName = System.getProperty(SERVLET_CONTEXT_WRAPPER_IMPL);
if (implClassName == null || implClassName.trim().equals("")) {
implClassName = DEFAULT_SERVLET_CONTEXT_WRAPPER_IMPL;
}
AbstractServletContextWrapper wrapper = null;
try {
Class clazz = Class.forName(implClassName);
Object[] args = new Object[] { originalContext };
Constructor constructor = clazz.getConstructor(
new Class[] { ServletContext.class} );
wrapper = (AbstractServletContextWrapper)
constructor.newInstance(args);
} catch (Throwable th) {
throw new ChainedRuntimeException("Failed to create "
+ "servlet context wrapper for Cactus.", th);
}
return wrapper;
}
public AbstractHttpServletRequestWrapper createHttpServletRequestWrapper(
HttpServletRequest originalRequest,
ServletURL servletUrl)
throws ChainedRuntimeException {
String implClassName = System.getProperty(
HTTP_SERVLET_REQUEST_WRAPPER_IMPL);
if (implClassName == null || implClassName.trim().equals("")) {
implClassName = DEFAULT_HTTP_SERVLET_REQUEST_WRAPPER_IMPL;
}
AbstractHttpServletRequestWrapper wrapper = null;
try {
Class clazz = Class.forName(implClassName);
Object[] args = new Object[] { originalRequest, servletUrl };
Constructor constructor = clazz.getConstructor(new Class[] {
HttpServletRequest.class,
ServletURL.class } );
wrapper = (AbstractHttpServletRequestWrapper)
constructor.newInstance(args);
} catch (Throwable th) {
throw new ChainedRuntimeException("Failed to create "
+ "HTTP servlet request wrapper for Cactus.", th);
}
return wrapper;
}
}
Best Regards.
--
ZHENG Zhong
1 Avenue Alphand
75116 Paris, France
+33 6 76 80 45 90
http://heavyz.sourceforge.net
http://heavyz.blogspot.com
http://spaces.msn.com/members/zhengzhong
