EDIT

package eu.etaxonomy.cdm.server.instance;

import java.lang.reflect.InvocationTargetException;

import java.sql.Connection;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import javax.sql.DataSource;

import org.apache.log4j.Logger;

import org.eclipse.jetty.plus.jndi.Resource;

import org.eclipse.jetty.server.handler.ContextHandler.Context;

import org.eclipse.jetty.util.component.LifeCycle;

import org.eclipse.jetty.util.component.LifeCycle.Listener;

import org.eclipse.jetty.webapp.WebAppContext;

import com.mchange.v2.c3p0.DataSources;

public class CdmInstance implements Listener {

    private static final Logger logger = Logger.getLogger(CdmInstance.class);

    private WebAppContext webAppContext = null;

    private Configuration configuration;

    private List<String> problems;

    private Status status = Status.uninitialized;

    private Resource jndiDataSource;

    public CdmInstance(Configuration configuration) {

        this.configuration = configuration;

    }

    public List<String> getProblems() {

        if (problems == null) {

            problems = new ArrayList<String>();

        }

        return problems;

    }

    public void clearProblems() {

        getProblems().clear();

    }

    public boolean onError() {

        return status.equals(Status.error);

    }

    /**

     * @param status

     *            the status to set

     */

    public void setStatus(Status status) {

        this.status = status;

    }

    /**

     * @return the status

     */

    public Status getStatus() {

        return status;

    }

    /**

     * @return true if status is not {@link Status#disabled}

     */

    public boolean isEnabled() {

        return !status.equals(Status.disabled);

    }

    /**

     * @return the configuration

     */

    public Configuration getConfiguration() {

        return configuration;

    }

    /**

     * @return the configuration

     */

    public void setConfiguration(Configuration configuration) {

        this.configuration = configuration;

    }

    /**

     * @return the webAppContext

     */

    public WebAppContext getWebAppContext() {

        return webAppContext;

    }

    /**

     * @return the webAppContext

     */

    public void setWebAppContext(WebAppContext webAppContext) {

        this.webAppContext = webAppContext;

    }

    public String getName() {

        return getConfiguration().getInstanceName();

    }

    /**

     * @param <T>

     * @param webAppContext

     * @param attributeName

     * @param type

     * @return

     */

    @SuppressWarnings("unchecked")

    private <T> T getServletContextAttribute(WebAppContext webAppContext, String attributeName, Class<T> type) {

        Context servletContext = webAppContext.getServletContext();

        Object value = servletContext.getInitParameter(attributeName);

        if (value != null && type.isAssignableFrom(value.getClass())) {

        }

        return (T) value;

    }

    @Override

    public void lifeCycleStopping(LifeCycle event) {

        logger.info("lifeCycleStopping");

        if(!getStatus().equals(Status.removed)){

            // never override Status.removed !!!

            setStatus(Status.stopping);

        }

    }

    @Override

    public void lifeCycleStopped(LifeCycle event) {

        logger.info("lifeCycleStopped");

        if(!getStatus().equals(Status.removed)){

            // never override Status.removed !!!

            setStatus(Status.stopped);

        }

    }

    @Override

    public void lifeCycleStarting(LifeCycle event) {

        logger.info("lifeCycleStarting");

        setStatus(Status.starting);

    }

    @SuppressWarnings("unchecked")

    @Override

    public void lifeCycleStarted(LifeCycle event) {

        logger.info("lifeCycleStarted");

        List<String> messages = getServletContextAttribute(webAppContext, SharedAttributes.ATTRIBUTE_ERROR_MESSAGES, List.class);

        String dataSourceName = getServletContextAttribute(webAppContext, SharedAttributes.ATTRIBUTE_DATASOURCE_NAME, String.class);

        if (messages != null && dataSourceName != null) {

            // Problems with instance

            Status errorStatus = Status.error;

            for(String message : messages){

                if(message.startsWith("Incompatible version")){

                    errorStatus = Status.incompatible_version;

                    break;

                }

            }

            setStatus(errorStatus);

            getProblems().addAll(messages);

            try {

                logger.warn("Stopping context '" + dataSourceName + "' due to errors reported in ServletContext");

                webAppContext.stop();

                setStatus(errorStatus);

            } catch (Exception e) {

                logger.error(e);

            }

        } else {

            // Instance is OK

            setStatus(Status.started);

        }

    }

    @Override

    public void lifeCycleFailure(LifeCycle event, Throwable cause) {

        logger.error("lifeCycleFailure");

        if(!getStatus().equals(Status.removed)){

            // never override Status.removed !!!

            setStatus(Status.error);

        }

        getProblems().add(cause.getMessage());

    }

    public void releaseWebAppContext() {

        webAppContext = null;

    }

    public boolean bindJndiDataSource() {

        try {

            Class<DataSource> dsCass = (Class<DataSource>) Thread.currentThread().getContextClassLoader().loadClass("com.mchange.v2.c3p0.ComboPooledDataSource");

            DataSource datasource = dsCass.newInstance();

            dsCass.getMethod("setDriverClass", new Class[] {String.class}).invoke(datasource, new Object[] {configuration.getDriverClass()});

            dsCass.getMethod("setJdbcUrl", new Class[] {String.class}).invoke(datasource, new Object[] {configuration.getDataSourceUrl()});

            dsCass.getMethod("setUser", new Class[] {String.class}).invoke(datasource, new Object[] {configuration.getUsername()});

            dsCass.getMethod("setPassword", new Class[] {String.class}).invoke(datasource, new Object[] {configuration.getPassword()});

            Connection connection = null;

            String sqlerror = null;

            try {

                connection = datasource.getConnection();

                connection.close();

            } catch (SQLException e) {

                sqlerror = "Can not establish connection to data base " + configuration.getDataSourceUrl() + " [sql error code: "+ e.getSQLState() + "]";

                getProblems().add(sqlerror);

                setStatus(Status.error);

                if(connection !=  null){

                    try {connection.close();} catch (SQLException e1) { /* IGNORE */ }

                }

                logger.error(configuration.toString() + " has problem : "+ sqlerror );

            }

            if(!onError()){

                logger.info("binding jndi datasource at " + configuration.getJdbcJndiName() + " with " + configuration.getUsername() +"@"+ configuration.getDataSourceUrl());

                jndiDataSource = new Resource(configuration.getJdbcJndiName(), datasource);

                return true;

            }

        } catch (IllegalArgumentException e) {

            logger.error(e);

            e.printStackTrace();

        } catch (SecurityException e) {

            logger.error(e);

        } catch (ClassNotFoundException e) {

            logger.error(e);

        } catch (InstantiationException e) {

            logger.error(e);

        } catch (IllegalAccessException e) {

            logger.error(e);

        } catch (InvocationTargetException e) {

            logger.error(e);

        } catch (NoSuchMethodException e) {

            logger.error(e);

        } catch (NamingException e) {

            logger.error(e);

        }

        return false;

    }

    public void unbindJndiDataSource() {

        if(jndiDataSource == null) {

            return; // nothing to to

        }

        try {

            InitialContext ic = new InitialContext();

            Object o = ic.lookup(jndiDataSource.getJndiNameInScope());

            if(o instanceof DataSource) {

                DataSources.destroy((DataSource) o);

                logger.info("datasource for " + jndiDataSource.getJndiNameInScope() + " destroyed");

            }

        } catch (NamingException e) {

            logger.error(e);

        } catch (SQLException e) {

            logger.error(e);

        }

        if(jndiDataSource != null){

            jndiDataSource.release();

            jndiDataSource = null;

        }

    }

}