TransactionScopedContextImpl.java

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package org.glassfish.cdi.transaction;

import javax.enterprise.context.ContextNotActiveException;
import javax.enterprise.context.spi.Context;
import javax.enterprise.context.spi.Contextual;
import javax.enterprise.context.spi.CreationalContext;
import javax.enterprise.inject.spi.PassivationCapable;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.Status;
import javax.transaction.cdi.TransactionScoped;
import javax.transaction.TransactionSynchronizationRegistry;
import java.lang.annotation.Annotation;

/**
 * The Context implementation for obtaining contextual instances of {@link TransactionScoped} beans.
 * <p/>
 * The contextual instances are destroyed when the transaction completes.
 * <p/>
 * Any attempt to call a method on a {@link TransactionScoped} bean when a transaction is not active will result in a
 * {@Link javax.enterprise.context.ContextNotActiveException}.
 *
 * @author <a href="mailto:j.j.snyder@oracle.com">JJ Snyder</a>
 */
public class TransactionScopedContextImpl implements Context {
    private static final String TRANSACTION_SYNCHRONIZATION_REGISTRY_JNDI_NAME = "java:comp/TransactionSynchronizationRegistry";

    @Override
    public Class<? extends Annotation> getScope() {
        return TransactionScoped.class;
    }

    @Override
    public <T> T get(Contextual<T> contextual, CreationalContext<T> creationalContext) {
        TransactionSynchronizationRegistry transactionSynchronizationRegistry = getTransactionSynchronizationRegistry();
        Object beanId = getContextualId(contextual);
        T contextualInstance = getContextualInstance(beanId, transactionSynchronizationRegistry);
        if (contextualInstance == null) {
            contextualInstance = createContextualInstance(contextual, beanId, creationalContext, transactionSynchronizationRegistry);
        }

        return contextualInstance;
    }

    @Override
    public <T> T get(Contextual<T> contextual) {
        TransactionSynchronizationRegistry transactionSynchronizationRegistry = getTransactionSynchronizationRegistry();
        Object beanKey = getContextualId(contextual);
        return getContextualInstance(beanKey, transactionSynchronizationRegistry);
    }

    @Override
    /**
     * Determines if this context object is active.
     *
     * @return true if there is a current global transaction and its status is
     *              {@Link javax.transaction.Status.STATUS_ACTIVE}
     *         false otherwise
     */
    public boolean isActive() {
        try {
             if (getTransactionSynchronizationRegistry() != null) {
                return true;
            }
        } catch (ContextNotActiveException ignore) {
        }
        return false;
    }

    private Object getContextualId(Contextual<?> contextual) {
        if (contextual instanceof PassivationCapable) {
            PassivationCapable passivationCapable = (PassivationCapable) contextual;
            return passivationCapable.getId();
        } else {
            return contextual;
        }
    }

    private <T> T createContextualInstance(Contextual<T> contextual,
                                           Object contextualId,
                                           CreationalContext<T> creationalContext,
                                           TransactionSynchronizationRegistry transactionSynchronizationRegistry) {
        TransactionScopedBean<T> transactionScopedBean = new TransactionScopedBean<T>(contextual, creationalContext);
        transactionSynchronizationRegistry.putResource(contextualId, transactionScopedBean);
        transactionSynchronizationRegistry.registerInterposedSynchronization(transactionScopedBean);
        return transactionScopedBean.getContextualInstance();
    }

    private <T> T getContextualInstance(Object beanId, TransactionSynchronizationRegistry transactionSynchronizationRegistry) {
        TransactionScopedBean<T> transactionScopedBean = (TransactionScopedBean<T>) transactionSynchronizationRegistry.getResource(beanId);
        if (transactionScopedBean != null) {
            return transactionScopedBean.getContextualInstance();
        }

        return null;
    }

    private TransactionSynchronizationRegistry getTransactionSynchronizationRegistry() {
        TransactionSynchronizationRegistry transactionSynchronizationRegistry;
        try {
            InitialContext initialContext = new InitialContext();
            transactionSynchronizationRegistry =
                (TransactionSynchronizationRegistry) initialContext.lookup(TRANSACTION_SYNCHRONIZATION_REGISTRY_JNDI_NAME);
        } catch (NamingException ne) {
            throw new ContextNotActiveException("Could not get TransactionSynchronizationRegistry", ne);
        }

        int status = transactionSynchronizationRegistry.getTransactionStatus();
        if ( status == Status.STATUS_ACTIVE ||
             status == Status.STATUS_MARKED_ROLLBACK ||
             status == Status.STATUS_PREPARED ||
             status == Status.STATUS_UNKNOWN ||
             status == Status.STATUS_PREPARING ||
             status == Status.STATUS_COMMITTING ||
             status == Status.STATUS_ROLLING_BACK ) {
            return transactionSynchronizationRegistry;
        }

        throw new ContextNotActiveException("TransactionSynchronizationRegistry status is not active.");
    }
}