HbDataStoreWithDataSource.java:

package de.sebthom.util;

import java.sql.*;
import java.util.Properties;
import javax.sql.DataSource;
import org.eclipse.emf.teneo.PersistenceOptions;
import org.eclipse.emf.teneo.hibernate.HbSessionDataStore;
import org.hibernate.HibernateException;
import org.hibernate.cfg.*;
import org.hibernate.connection.ConnectionProvider;

/**
 * @author Sebastian Thomschke
 */
public class HbDataStoreWithDataSource extends HbSessionDataStore {
  public final static class CustomConnectionProvider implements ConnectionProvider {
    private DataSource ds;

    public void close() throws HibernateException { }

    public void closeConnection(final Connection conn) throws SQLException {
      conn.close();
    }

    public void configure(final Properties props) throws HibernateException {
      ds = _CONFIG_TIME_DS_HOLDER.get();
    }

    public Connection getConnection() throws SQLException {
      return ds.getConnection();
    }

   public boolean supportsAggressiveRelease() {
     return false;
   }
  }

  private static final long serialVersionUID = 1L;
  private static HbDataStoreWithDataSource INSTANCE;

  /**
   * the data source holder acts as a thread safe bridge between the DSConnectionProvider which is instantiated by Hibernate internally
   * and the data source injected into the session factory during spring configuration time.
   */
  private static final ThreadLocal _CONFIG_TIME_DS_HOLDER = new ThreadLocal();

  public static HbDataStoreWithDataSource getInstance() {
		return INSTANCE;
  }

  private final Properties props = new Properties();

  public HbDataStoreWithDataSource() {
    INSTANCE = this;

    props.setProperty(PersistenceOptions.ADD_INDEX_FOR_FOREIGN_KEY, "true");
    props.setProperty(PersistenceOptions.FETCH_CONTAINMENT_EAGERLY, "false");
    props.setProperty(PersistenceOptions.FETCH_ASSOCIATION_EXTRA_LAZY, "false");

    // tell Teneo to not change the table names, we do this using Hibernate's ImprovedNamingStrategy
    props.setProperty(PersistenceOptions.SQL_CASE_STRATEGY, "none");
    props.setProperty(PersistenceOptions.MAXIMUM_SQL_NAME_LENGTH, "-1");
  }

  protected Configuration createConfiguration() {
    Configuration cfg = super.createConfiguration();
    cfg.setNamingStrategy(ImprovedNamingStrategy.INSTANCE);

    // only if a DS is injected we register our connection provider
    if (_CONFIG_TIME_DS_HOLDER.get() != null)
      cfg.setProperty(Environment.CONNECTION_PROVIDER, CustomConnectionProvider.class.getName());
    return cfg;
  }

  public void setDataSource(final DataSource ds) {
    _CONFIG_TIME_DS_HOLDER.set(ds);
  }

  public final void setHibernateProperties(final Properties hibernateProperties) {
    throw new UnsupportedOperationException();
  }

  public final void setPersistenceProperties(final Properties persistenceOptions) {
    throw new UnsupportedOperationException();
  }

  public void setProperties(final Properties props) {
    this.props.putAll(props);
    super.setProperties(this.props);
  }
}

web.xml:

  openSessionInViewFilter
  org.springframework.orm.hibernate3.support.OpenSessionInViewFilter
    
singleSession
true
    
    
sessionFactoryBeanName
realSessionFactory
    


  openSessionInViewFilter
  /*
  REQUEST
  ERROR

applicationContext.xml:

  

  

      
${jdbc.driverClassName}
${jdbc.url}
${jdbc.username}
${jdbc.password}
false
${jdbc.maxConnections}
${jdbc.minConnections}
10000
${jdbc.minConnections}
${jdbc.validationQuery}
false
true
1200000
1800000
5
      
    
  

  

      hibernate.dialect=${hibernate.dialect}
      hibernate.hbm2ddl.auto=${hibernate.hbm2ddl.auto}
      hibernate.jdbc.batch_size=2000
      hibernate.show_sql=${hibernate.show_sql}
      hibernate.transaction.auto_close_session=false
      hibernate.current_session_context_class=org.springframework.orm.hibernate3.SpringSessionContext
      hibernate.transaction.factory_class=org.springframework.orm.hibernate3.SpringTransactionFactory
    

com.acme.ShopPackageImpl
  

  

  

  

Comments:

1. VERY IMPORTANT:The HibernateTransactionManager does NOT get the teneoSessionFactory(HbSessionDataStore) object passed in as sessionFactory, but the underlying Hibernate SessionFactory that can be retrieved from the HbSessionDataStore via the getSessionFactory() method. Not doing so will result in duplicate Hibernate Sessions completely breaking the transaction managment. This happens because in that case the TransactionSynchronizationManager will sometimes internally bind the hibernate session to the current thread based on different keys and thus does not find it again. Here are some stacktraces showing the problem:

   TransactionSynchronizationManager.bindResource(Object, Object) line: 170
   at OpenSessionInViewFilter.doFilterInternal(HttpServletRequest, HttpServletResponse, FilterChain) line: 183
   => results in TransactionSynchronizationManager.bindResource(HbSessionDataStore, SessionHolder) => as key the Teneo SessionFactory is used
   
   TransactionSynchronizationManager.bindResource(Object, Object) line: 170
   at SessionFactoryUtils.doGetSession(SessionFactory, Interceptor, SQLExceptionTranslator, boolean) line: 339
   at SessionFactoryUtils.doGetSession(SessionFactory, boolean) line: 256
   at SpringSessionContext.currentSession() line: 60
   at SessionFactoryImpl.getCurrentSession() line: 700
   at HbSessionDataStore(HbBaseSessionDataStore).getCurrentSession() line: 161
   => results in TransactionSynchronizationManager.bindResource(SessionFactoryImpl, SessionHolder) => as key the Hibernate SessionFactory is used
   
   TransactionSynchronizationManager.bindResource(Object, Object) line: 170
   at HibernateTransactionManager.doBegin(Object, TransactionDefinition) line: 577
   at HibernateTransactionManager(AbstractPlatformTransactionManager).getTransaction(TransactionDefinition) line: 371
   at TransactionInterceptor(TransactionAspectSupport).createTransactionIfNecessary(PlatformTransactionManager, TransactionAttribute, String) line: 316
   at TransactionInterceptor.invoke(MethodInvocation) line: 105
   at ReflectiveMethodInvocation.proceed() line: 172
   => results in TransactionSynchronizationManager.bindResource(HbSessionDataStore, SessionHolder) => as key the Teneo SessionFactory is used
   

2. defaultAutoCommit is set to false to ensure that Spring has full control over the transaction and that the connection pool is not committing statements automatically based on it’s own strategies.
3. The example uses an extended version of the org.eclipse.emf.teneo.hibernate.HbSessionDataStore class that allows the usage of a DataSource object and that configures Teneo to not alter the table, column names but let’s Hibernate handle this via its ImprovedNamingStrategy.
4. hibernate.transaction.auto_close_session is set to false to avoid “SessionException: Session is closed!” in conjunction with the OpenSessionInViewListener.
5. hibernate.current_session_context_class and hibernate.transaction.factory_class are set to special Spring implementations to avoid “org.hibernate.HibernateException: No CurrentSessionContext configured!” when not using Spring Hibernate Template via HibernateDAOSupport. It is not recommended to use the Hibernate Template anymore, see http://blog.springsource.com/2007/06/26/so-should-you-still-use-springs-hibernatetemplate-andor-jpatemplate/

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Post tags: dbcp, emf, hibernate, Java, persistence, spring, teneo, transaction

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EPropertyModel

If you are working with EMF (Eclipse Modeling Framework) generated model classes you can also use PropertyModels to bind structural features (properties in EMF terminology) of an EObject to a Wicket component. E.g. if your EObject has an attribute called “comment” you could instantiate a model like this

IModel model = new PropertyModel(myEObject, "comment");

This approach has several disadvantages. First, the name of the attribute is declared as a String and not as a compile-time reference to the actual attribute. This means the application could break during runtime if you have renamed the attribute at one point and forgot to also change the String value. Second, this property model uses runtime reflection which is a slow alternative to compile time based access.
Java classes generated from EMF Models by default extend the EObject class which provides a compile-time reflection API. Using the generic eGet and eSet methods any public property of the EObject can be accessed. The EMF Generator also generates a Package class for each EMF package that holds a Literals interface listing all available attributes and references of all generated EClasses of the given package. If you lets say have an EClass “Ticket” with the attribute “comment” in the package “com.acme.service” you could utilize the compile time reflection API as follows:

EAttribute commentAttribute = com.acme.service.ServicePackage.Literals.TICKET__COMMENT;
Ticket newTicket = com.acme.service.ServiceFactory.eINSTANCE.create(Ticket.class);
newTicket.eSet(commentAttribute, "my comment");

Using the EMF compile-time reflection API I created a generic EMF ECore Feature Model implementation that leverages the compile-time references to structural features. Most of the code is actually related to working around the fact that EAttributes and EReferences are not serializable but which they should to be part safely referenced in a model that potentially is serialized by Wicket between requests.

import org.apache.wicket.model.IDetachable;
import org.apache.wicket.model.IObjectClassAwareModel;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EClassifier;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EPackage;
import org.eclipse.emf.ecore.EStructuralFeature;

/**
 * A property model to bind an attribute of an EMF ECore object
 *
 * @author Sebastian Thomschke
 */
@SuppressWarnings("unchecked")
public class EFeatureModel<T> implements IObjectClassAwareModel<T>
{
	private static final long serialVersionUID = 1L;

	private transient EStructuralFeature feat;
	private String featContainerClassName;
	private String featName;
	private String featPackageNsURI;

	private EObject target;

	public EFeatureModel(EObject target, EStructuralFeature efeature)
	{
		this.target = target;
		this.feat = efeature;
		this.featName = efeature.getName();
		this.featContainerClassName = efeature.getContainerClass().getName();
		this.featPackageNsURI = ((EPackage) efeature.eContainer().eContainer()).getNsURI();
	}

	public void detach()
	{
		if (target instanceof IDetachable) ((IDetachable) target).detach();
	}

	public EStructuralFeature getFeature()
	{
		if (feat == null)
		{
			EPackage ePackage = EPackage.Registry.INSTANCE.getEPackage(featPackageNsURI);
			for (Object eClassifierItem : ePackage.getEClassifiers())
			{
				EClassifier eClassifier = (EClassifier) eClassifierItem;
				if (eClassifier.getInstanceClass().getName().equals(featContainerClassName))
					feat = ((EClass) eClassifier).getEStructuralFeature(featName);
			}
		}
		return feat;
	}

	public T getObject()
	{
		return (T) target.eGet(getFeature());
	}

	public Class<T> getObjectClass()
	{
		return getFeature().getEType().getInstanceClass();
	}

	public void setObject(T object)
	{
		// do nothing if the object is the same instance that is returned by the getter
		// this is esp. important for collection properties
		if (target.eGet(getFeature()) == object) return;

		target.eSet(getFeature(), object);
	}

	@Override
	public String toString()
	{
		return new StringBuilder("Model:classname=[").append(getClass().getName()).append("]").append(":target=[")
				.append(target).append("]").toString();
	}
}

Using this new model implementation is as simple as using the PropertyModel provided by Wicket:

IModel model = new EFeatureModel(myTicket, com.acme.service.ServicePackage.Literals.TICKET__COMMENT);

You can now fully enjoy the compile-time safeness of your EMF model.

Making EObjects serializable

Wicket usually serializes components and their associated models between HTTP requests. If you are using the provided EPropertyModel your EObject classes must implement the Serializable interface. To achieve this, simply extend the EObject interface with the Serializables interface and set “Root Extends Interface” property in your genmodel configuration to this interface.

/**
 * @author Sebastian Thomschke
 */
public interface SerializableEObject extends EObject, Serializable {
}

When you now regenerate the model classes they will extend the SerializableEObject interface and Wicket will stop complaining about objects in the model being not serializable.

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Post tags: eclipse, ecore, emf, Java, reflection, wicket

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Installing Sun Java 6

Ensure the non-free section is enabled for the APT repository configuration in /etc/apt/sources.list, e.g. “deb http://ftp.de.debian.org/debian testing main contrib non-free”

apt-get update
apt-get install sun-java6-jdk
echo 'JAVA_HOME="/usr/lib/jvm/java-6-sun"' >> /etc/environment
echo 'JRE_HOME="/usr/lib/jvm/java-6-sun/jre"' >> /etc/environment

Installing Tomcat 6

apt-get install tomcat6 tomcat6-admin
/etc/init.d/tomcat6 stop

Creating standard Tomcat directory layout

mkdir /opt/tomcat
cd /opt/tomcat
ln -s /etc/tomcat6/ conf
ln -s /usr/share/tomcat6/bin/ bin
ln -s /usr/share/tomcat6/lib/ lib
ln -s /var/lib/tomcat6/webapps webapps
ln -s /var/log/tomcat6/ logs

Creating a Tomcat admin user

In /opt/tomcat/conf/tomcat-users.xml add an entry like:

<user name="ADMIN_USERNAME" password="ADMIN_PASSWORD" roles="admin,manager" />

Setting up virtual hosts

For each virtual host execute the following command. Replace “mydomain.com” with the desired virtual host name, but omit the “www.” part.

mkdir -p /opt/tomcat/webapps.mydomain.com/ROOT

In the <Engine> tag of “/opt/tomcat/conf/server.xml” add one host entry for each virtual host.

<Host name="mydomain.com" appBase="/opt/tomcat/webapps.mydomain.com">
    <Alias>www.mydomain.com>/Alias>
    <Valve className="org.apache.catalina.valves.AccessLogValve" prefix="mydomain_access_log." suffix=".txt" pattern="common"/>
</Host>

The <Alias> tag tells Tomcat to redirect from www.mydomain.com to mydomain.com.
The <Valve> tag enables access logging in the standard logging format.

Using xinetd to configure port 80 for Tomcat

Binding a service on port 80 requires root permissions. Thus we use port forwarding to “bind” Tomcat to port 80. My VPS does not support the use of “iptables -j REDIRECT” therefore I am using xinetd as a web proxy.
Ensure that no other service is listening on port 80/443:

netstat -pan | grep ":80\|:443"

Register the required xinetd services:

echo echo "
service www
{
        socket_type     = stream
        protocol        = tcp
        user            = root
        wait            = no
        bind            = 88.80.198.181
        port            = 80
        redirect        = localhost 8080
        disable         = no
        flags           = REUSE
        log_type        = FILE /var/log/wwwaccess.log
        log_on_success  -= PID HOST DURATION EXIT

        per_source      = UNLIMITED
        instances       = UNLIMITED
}

service https
{
        socket_type     = stream
        protocol        = tcp
        user            = root
        wait            = no
        bind            = 88.80.198.181
        port            = 443
        redirect        = localhost 8443
        disable         = no
        flags           = REUSE
        log_type        = FILE /var/log/httpsaccess.log
        log_on_success  -= PID HOST DURATION EXIT

        per_source      = UNLIMITED
        instances       = UNLIMITED
}
" > /etc/init.d/tomcat
/etc/init.d/xinetd restart

If you want to use a different service name, e.g. “tomcat” instead of “www” you must add this service to /var/services, e.g. “tomcat 80/tcp”
In /opt/tomcat/conf/server.xml modify the <Connector> as follows:

<Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" proxyPort="80" address="127.0.0.1" />

This binds Tomcat to localhost. It also tells Tomcat that port 80 is the proxy port which is necessary for correct URL generation.
From now on the Tomcat admin applications are only accessible via localhost. You can use SSH port forwarding to still access the applications from your workstation’s web browser. E.g. if you are using PuTTY you can use this command line option “-L 8080:localhost:8080″ to forward the server’s local 8080 port to your workstation’s local 8080 port. On your workstation’s browser you then simply enter http://localhost:8080/manager/html and are connected to the server’s Tomcat admin application.

Enabling PHP support (optional)

Download Quercus.

mkdir -p /opt/downloads
wget -o /opt/downloads/quercus-4.0.3.war http://caucho.com/download/quercus-4.0.3.war

Install Quercus as a shared library.

unzip -j /opt/downloads/quercus-4.0.3.war \*.jar -d /opt/tomcat/lib

Enable PHP support for the virtual hosts by installing the quercus web.xml. For each virtual host execute:

unzip /opt/downloads/quercus-4.0.3.war *web.xml -d /opt/tomcat/webapps.mydomain.com/ROOT

Starting Tomcat

/etc/init.d/tomcat start

References

• Securing Linux for Java services: The port dilemma
• Redirect HTTP and HTTPS traffic to Tomcat’s ports
• Tomcat 6: Virtual Hosting How To
• Tomcat 6: Classloader How To
• Virtual Hosting with Tomcat
• Quercus: Tomcat
• How to install Tomcat 6 on Ubuntu 9.04 (Jaunty)

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Post tags: Java, PHP, port 80, port forwarding, quercus, tomcat, vhost, virtual servers, VPS, xinetd

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Here comes a module I wrote to provide this kind of functionality. It uses the mechanism described here http://java.sun.com/developer/technicalArticles/Security/pwordmask/ to mask characters entered at the command prompt. Additionally if Java 6 or higher is running Jython the module will instead use the new Console.readPassword() method. In case the module is running in an environment where the getpass module is available it will delegate to the corresponding methods of this module instead of using its own implementations.

# ext_getpass.py
# @author Sebastian Thomschke, http://sebthom.de/
import thread, sys, time, os

# exposed methods:
__all__ = ["getpass","getuser"]

def __doMasking(stream):
    __doMasking.stop = 0
    while not __doMasking.stop:
        stream.write("b*")
        stream.flush()
        time.sleep(0.01)

def generic_getpass(prompt="Password: ", stream=None):
    if not stream:
        stream = sys.stderr
    prompt = str(prompt)
    if prompt:
        stream.write(prompt)
        stream.flush()
    thread.start_new_thread(__doMasking, (stream,))
    password = raw_input()
    __doMasking.stop = 1
    return password

def generic_getuser():
    for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
        usr = os.environ.get(name)
        if usr: return usr

def java6_getpass(prompt="Password: ", stream=None):
    if not stream:
        stream = sys.stderr
    prompt = str(prompt)
    if prompt:
        stream.write(prompt)
        stream.flush()

    from java.lang import System
    console = System.console()
    if console == None:
	    return generic_getpass(prompt, stream)
    else:
        return "".join(console.readPassword())

try:
    # trying to use Python's getpass implementation
    import getpass
    getpass = getpass.getpass
    getuser = getpass.getuser
except ImportError, e:
    getuser = generic_getuser

    # trying to use Java 6's Console.readPassword() implementation
    try:
        from java.io import Console
        getpass = java6_getpass
    except ImportError, e:
        # use the generic getpass implementation
        getpass = generic_getpass

Here is an usage example:

import ext_getpass as getpass

pw = getpass.getpass("Please enter your password:")
print "The entered password was: " + pw

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Post tags: Java, Jython, password, python

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[INFO] [compiler:compile]
[INFO] Compiling 180 source files to C:\projects\oval\src\trunk\target\classes
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Compilation failure
C:\projects\oval\src\trunk\src\main\java\net\sf\oval\Validator.java:[373,58]
addMethodParameterChecks(java.lang.reflect.Method,int,java.lang.Object)
has private access in net.sf.oval.internal.ClassChecks 

There exist multiple methods named addMethodParameterChecks in the class ClassChecks with different signatures. The problem is that javac tries to link against the wrong method when compiling the class calling one of the methods.

(...)
Read the rest of Sun JDK5/6 compilers broken when linking overloaded methods with variable arguments (284 words)

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Post tags: bug, compiler, Java, jdk

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Web sebthom.de

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Post tags: Java

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Visit the project page at http://sourceforge.net/projects/oval/

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Post tags: Java, oval

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